Soils
Introduction: Soil Formation under Arctic Conditions
(EA-PS. C. C. Nikiforoff)
INTRODUCTION: SOIL FORMATION UNDER ARCTIC CONDITIONS
CONTENTS
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Pag
e
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Soil Dynamics
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1
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Sources of Pedogenic Energy
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3
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Perennial Freezing of the Ground
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6
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Tundra Type of Soil Formation
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11
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Biological Factors of Soil formation
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12
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Thermal Conditions of Soil Formation
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16
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Hydrologic Regime of Tundra Soils
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18
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Solifluction
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21
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Frost Blisters and Involution
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23
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Tundra Complexes
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27
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Bibliography
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33
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EA-Plant Sciences
[C. C. Nikiforoff]
INTRODUCTION: SOIL FORMATION UNDER ARCTIC CONDITIONS
Soil Dynamics
Soils of any natural region are neither better nor worse than are the
regions, their climate, vegetation, and geological history. Evaluated by the
standards of any region in the temperate belt the soils of the Arctic are very
poor indeed. If, however, it were possible to detach bodily the best agricul–
tural soil from its habitat and to reassemble it in the Arctic giving no further
protection from the elements of the environment, than very soon it would cease
to fare such better than the native soil. Nor would the poorest tundra soil,
being similarly transferred to the corn belt retain very long its original
character. It would not, indeed, produce immediately as high a yield of corn
as a native soil, but in a relatively few years it would be able to support a
higher yield than it supported in the Arctic.
In both instances the transplanted soils would be immediately attacked by
the local conditions which would tend to eradicate the original properties of
the introduced soils and to impart to them the characteristics common to the
region. Sooner or later the newcomers would be thoroughly naturalized.
Hence, the properties of the soil are not fixed. Soils are capable of
changes leading toward adjustment to a
[:
]
flexible environment. In a geological
EA-Ps. Nikiforoff: Introduction
perspective the environment is not static and every change in it is accompanied
by a corresponding change in the soil. At a given time the character of the
soil mirrors the conditions of the geographical landscape existing at that time.
It might have been different in the past and it may change again in the future.
The soil is a dynamic system. “Soil dynamics” means a totality of movements
which continuously are taking place in the soil. Some movements are fast, others
are very slow. Some of them are accomplished in a split second, while others
continue for many years, Some movements affect only minute quantities of matter,
say individual atoms or ions, whereas others represent shifting of many tons of
material. Again, some of them are confined within a single molecule, and others
cover great distances. Solifluction is a movement and so is the replacement of
one exchangeable ion by another. Percolation of water, flows of heat, swelling
of the soil aggregates on wetting, contraction and cracking of the soil mass on
drying or freezing, emission of carbon dioxide, and leaching of soluble salts
from the soils into the ocean — all these are various movements which collectively
represent soil dynamics.
Ceaseless movements are taking place, especially near the surface of the
earth’s crust. This agitation rapidly diminishes with depth. At a depth of just
a few tens of feet most of these movements either stop altogether or become
geologically slow.
There is no sharp line of demarcation between the relatively static sub–
stratum and its dynamic geological skin. Therefore, the thickness of the activated
skin cannot be measured precisely. The soil represents the uppermost and,
naturally, the most active part of the skin, especially the part in which the
dynamics are maintained largely by living organisms.
EA-PS. Nikiforoff: Introduction
The movements which collectively represent the soil dynamics are not
accidental or chaotic. They are precisely co-ordinated, interdependent, and
controlled by various mechanical, physical, and chemical laws. In other words,
they represent the work of a mechanism or a system. That is why the soil is
defined as a dynamic system.
Only the most dramatic manifestations of soil dynamics can be observed
directly. Most of the individual movements are either much too slow to be
noticed or made by such small quantities of matter that their registration
requires the use of precision instruments or chemical analyses. A great deal
more can be learned about soil dynamics through analysis of its summary effects.
Every movement is a change of place or position; hence, every movement
leaves some trace in the medium in which it takes place. The traces of indi–
vidual movements may or may not be caught by our instruments, but collectively
they impart to the initial medium a set of new properties or give to such a
medium a new morphological as well as chemical profile. These profiles are
the records of performances of soil systems.
Each single movement represents a certain amount of work and all work consumes
a certain amount of energy without which it cannot be performed and the system
cannot function. It follows that the soil, being a steadily working system,
must be continuously recharged with energy. This is the other essential feature
of a dynamic soil. Without recharging it is merely a static fossil or a sort of
geological mummy.
Sources of Pedogenic Energy
The principal sources of the thermal energy which activates the soil are solar
radiation and atomic decay of radioactive substances in the interior of the earth’s
EA-PS. Nikiforoff: Introduction
crust. The heat generated at these two sources flows into the soil from opposite
directions and will be referred to hereafter as vadose heat and phreatic (or
juvenile) heat, respectively. A much smaller quantity of heat is generated in
the soil itself by liberation of latent heat of crystallization in the decomposi–
tion of various endothermic mineral compounds such as aluminum silicates. Consi–
derably more heat is released by the decomposition of organic residues in the
soil. This heat, however, is only a part of the vadose energy which has been
intercepted by the plant before it reached the soil.
Usually it is assumed that the quantity of phreatic heat received by the
soil is negligibly small in comparison with the inflow of vadose heat and that
the temperature of the ground is maintained especially by insolation. This view,
however, is not entirely convincing. It may be computed, indeed, that the
amount of phreatic heat reaching the surface of the soil in a given area
during a year is many times smaller than the amount of vadose heat received by
this area during the same length of time. The difference ranges from nearly a
thousand times in the high latitudes to several thousand times in the tropics.
The temperature of the ground, however, represents not the heat which might be
obtained on the surface but the heat that has been transmitted inside. By far the
greater part of vadose heat is not used for warming the ground but is sent back
into the atmosphere in the form of long-wave (infrared) terrestrial radiation
without any thermal effect on the ground. Again, in higher latitudes the ground
is covered with snow for a large part of the year and the snow may reflect up
to 80% of the short-wave solar radiation. These and various other factors
greatly diminish the warming of the ground by vadose heat.
On the other hand, phreatic heat flows steadily, day and night, summer and
winter, and all of it passes through the ground with inevitable thermal effect.
EA-PS. Nikiforoff: Introduction
The uppermost layer of the ground including the soil may be visualized as
a thermal pool into which the two streams of heat empty. Since the tempera–
ture of the ground does not rise progressively, it follows that the capacity
of the pool to receive heat is limited to a certain level at which the excess
of heat is spilled away. In other words, the temperature of the ground is main–
tained at a certain level by the altitude of the thermal spillway. Observations
show that this level is within a very few degrees of the mean annual temperature
of the air above the ground. Hence, it appears that the inflow of vadose heat
builds a sort of thermal threshold or dam which determines the heat capacity
of the pool — the temperature of the upper layer of the ground.
The geothermal gradient shows that the flow of phreatic heat into the pool
is aggraded to this threshold. The temperature of the ground at the threshold
serves as the base level of the thermal drainage of the earth’s crust. Under
conditions of the established geothermal gradient the temperature of the ground
gradually increases with depth.
The elevation of the rim of the thermal pool is fairly constant at the
points of inflow of phreatic heat. Here the temperature of the ground is not
affected by diurnal and annual pulsations of the inflow of vadose heat and this
temperature serves as the base level of the geothermal gradient. The fact that
a relatively constant temperature of the ground is maintained at a very short
distance, usually some 20 or 30 feet, from the surface receiving vadose heat
indicates that the pressure of the flow of phreatic heat is much stronger than
could be expected on the basis of slowness of this flow, and that the role of
phreatic heat in warming the ground is by no means negligible.
All heat received at the thermal pool in excess of its capacity is discharge
.d
^
d.
^
Normally, this outflow is in one direction only, from the ground into the air,
EA-PS. Nikiforoff: Introduction
i.e., against the flow of vadose heat. Hence, vadose heat does not pass over
the barrier built in its way by the contraflow of phreatic heat, whereas the
latter steadily spills over the threshold formed by the inflow of vadose heat.
Penetration of vadose heat deeper into the ground takes place only under certain
specific conditions during the readjustment of the gradient which will be
discussed later.
Perennial Freezing of the Ground
The elevation of the thermal threshold varies with latitude from a maxi–mum in the tropics to a minimum in the polar regions. In the Arctic it generally
corresponds to a temperature of several degrees below the freezing point. The
significance of such a low threshold is that the geothermal gradient, sloping
to such a low base level, must cross the freezing point at some depth above
which the ground must be perenially frozen except for a very thin outer shell
which is subject to periodic defrosting by summer tides of vadose heat.
Under conditions of an established gradient the thickness of the layer of
frozen ground must be
[:
]
constant. It can change only by readjustment of the
gradient to a new base level which might be lowered or raised with geological
changes in climate. Under a steady condition the thickness of the frozen
ground is determined by the temperature at the base level of the gradient and
by the steepness of the gradient. The temperature at the base of the gradient
ranges from just a fraction of one degree below freezing to more than ten
degrees below zero in the Centigrade scale. The steepness of the geothermal
gradient is determined by the difference in temperature at the top and at the
base of the gradient, the distance between these two
[:
]
levels, and the
thermoconductivity of the medium transmitting the heat. It is assumed that
the difference in temperature might amount to about 1,200° to 1,400° C. and
EA-PS. Nikiforoff: Introduction
that the distance from the hearth of phreatic heat to the base of the gradient
is of the order of about ten to fifteen miles. It has been found that under
various regional and local conditions the thickness of frozen layers ranges from
several feet to more than a thousand feet.
The antiquity of deep freezing of the ground in high latitudes is not
precisely known. Some assume that freezing is a fairly recent phenomenon,
others believe that it originated in Pleistocene time, or, probably, even earlier.
Perhaps two different issues are confused in these discussions. One is the
general freezing of the upper shell of the earth’s crust in high latitudes; the
other the freeing of the ground in various particular regions.
Deep freezing of the ground in high latitudes is a geophysical phenomenon
which, in all likelihood, is just as old as the earth’s crust itself. It takes
place because of the globular shape of the planet and the fact that the surface in
high latitudes receives only a small amount of vadose heat. The base level of
the geothermal gradient could not be high at any time throughout geological
history in these latitudes. Therefore, deep freezing of the ground in high
latitudes could have been possible in all geological periods.
It does not follow, however, that the ground throughout the land
[:
]
masses
in high latitudes has been continuously frozen since the dawn of geological history.
Its freezing does not depend entirely upon the low mean temperature of the air
that is in contact with its surface. Various other factors affect the process.
Particularly significant is the insulation of the ground by ice, snow, water, or
vegetation and its residues. Some of these factors restrict the inflow of vadose
heat into the ground, others check the outflow of heat from the ground. In a
geological perspective, these conditions are not permanent. The ground might
freeze at some particular air temperature under one set of conditions but will not
EA-PS. Nikiforoff: Introduction
freeze at even lower mean temperature under other sets of conditions. Therefore,
notwithstanding an everlasting possibility of deep freezing in high latitudes,
the ground in particular regions might be frozen only temporarily.
The ground is perennially frozen to a considerable depth throughout enor–
mous areas in Eurasia and North America. Boundaries of these areas have not yet
been mapped accurately. Highly generalized schematic maps show the areas under–
lain by a continuous layer of frozen ground, similar areas which include
scattered tracts of land without a frozen layer, and areas generally free of a
frozen layer but including “islands” of frozen ground. The areas such as those
in the second and third mapping units, which presumably are free of frozen layers,
usually are those in which the ground is not frozen immediately below the depth
of annual winter freezing. It does not necessarily indicate that there are no
frozen layers at some greater depth. The absence of such layers can be ascertained
only by deep drilling and a study of the geothermal gradient.
Frozen layers, some of them up to a hundred feet thick and lying at a depth
of several scores of feet, are not uncommon along the periphery of the regions
affected by perennial ground frost. There can be hardly any doubt that these
deep layers of frozen ground are remnants of previous through freezing of the
ground from the surface downward. No layer of ground can freeze unless its heat
is emitted and this can take place only through a medium having a progressively
lower temperature. Hence, these layers could have been frozen only under the
condition that the entire ground above them also was frozen and had a tempera–
ture lower than their own.
Defrosting of the upper part of previously frozen ground indicates change
in climate and a slow regradation of the geothermal gradient toward a higher
base level. Thawing of the remnants of a frozen layer must proceed from above
EA-PS. Nikiforoff: Introduction
due to the inflow of vadose heat, and from below under the influence of phreatic
heat. In such cases penetration of the vadose heat to a considerable depth into
the ground is not obstructed by the contraflow of phreatic heat. These current
meet in the
lay
layer having the lowest temperature, i.e., somewhere within the
remaining frozen lens. Thus, it appears that islands which presumably are free
or ground frost lens. Thus, it appears that islands which presumably are free
of ground frost may or may not be actually free of it. Many of these islands
may represent nothing more than local depressions in the surface of a continuous
frozen sheet.
Local defrosting of the ground indicates that the general boundary of regions
that are affected by ground frost is not fixed. Depending upon changes in climate,
the frozen layer may
shi
shrink vertically as well as horizontally, or it may
expand. Consequently, various regions, especially in high middle latitudes —
for example, in eastern Siberia — may now be passing through different stages
of the process. Some parts of these regions are subject to a progressive def
or
^
ro
^
st–
ing, whereas others may suffer from enhanced freezing. Geophysical investigations
have not advanced enough for even a rough delineation of these various regions.
It appears fairly obvious, however, that it is entirely possible that some
regions where no frozen ground exists at the present time could have been affected
by ground frost, say in Pleistocene time or earlier, whereas other areas which
are now frozen were probably unaffected by perennial freezing in the past. These
various regions changes in geothermal regimes, however, represent hardly more than
local phase of the general geophysical phenomenon, which very likely began during
the earliest period of geological history and will end with the last chapter of
this history.
A deep perennial freezing of the ground takes places under conditions of low
mean annual temperature and low precipitation. Since these conditions prevail
EA-PS. Nikiforoff: Introduction
throughout the greater part of the Arctic, the ground is frozen to great depths
practically throughout this belt. Exceptions are found under sufficiently large
and deep bodies of water and, probably, under large glaciers.
Scant precipitation appears to be no less essential for the freezing of
the ground than negative mean temperature. Heavier precipitation, especially in
the form of snow, combined with low temperature, leads to the accumulation of
ice and eventual glaciations of the land which, probably, is rather antagonistic
to deep freezing of the ground. Under the blanket of thick ice whose temperature
near the ground appears to be about 0.0°C., the flow of phreatic heat cannot
fail to reach the sole of the ice sheet and start a slow but ceaseless undercutting
of the glacier.
Grigoriev describes the thermal balance of the Arctic as decidedly negative.
This means that on an annual basis the outflow of heat from the surface is greater
than the inflow. This concept, however, is open to criticism. With chronically
negative thermal balance the temperature of the ground should decrease progressively,
which generally is not the case. The decrease takes place only in connect
t
ion
with corresponding climatic changes; otherwise the temperature of the ground
remains steady.
Perhaps the idea of negative thermal balance is based on a somewhat erroneous
computation. The income of heat is derived from measurements of solar radiation.
The inflow of phreatic heat is disregarded as negligible. The outflow of heat
representing infrared terrestrial radiation, however, includes the emission of
both vadose and phreatic heat. Hence, the result shows an excess of outflow over
inflow of heat. It follows that the so-called “negative thermal balance” might
represent nothing more than the quantity of phreatic heat which reaches the surface
of the ground the spills over the thermal threshold into space. Computations are
EA-PS. Nikiforoff: Introduction
not by any means precise, indeed, and the result can be accepted only as a very
rough first approximation of the phenomenon.
Tundra Type of Soil Formation
Practically all arctic soils develop under exceedingly strong influence of
perennial freezing of the ground. Since the tundra represents the most typical
landscape of the arctic and a large part of the subarctic belts, the soils of
these regions usually are referred to as tundra soils. This is a very broad and
inclusive term, and the tundra group includes many different soils. Some of these
are formed on steep mountain slopes and others on broad plains, plateaus, marine
and stream terraces, and flat coastal lowlands. Some of them are stony, others
are stone-free, sandy, or clayey. Some tundra soils are boggy or marshy, whereas
others are relatively well drained. Some are covered by a layer of peat or fairly
compact fibrous tundra sod, whereas others are virtually bare. Again, some tundra
sols are developed form local residual rock waste, whereas others are from glacial
drifts, steam or marine sediments, and wind deposits. The common feature which
unites all these various soils is that they all develop under more or less similar
arctic climates. This, more than any other single factor, determines the general
trend of the peculiar tundra type of soil formation.
Glinka and some of his followers did not recognize an independent tundra type
of soil formation. According to Glinka, the tundra soils are nothing more than
underdeveloped or rudimental podsolic and bog soils. The influence of this view
is still fairly strong in soil s
ic
^
ci
^
ence. Reference to the so-called “pygmy podsols”
of drawf podsols are not infrequent in reports on arctic soils, although a general
group of tu
i
ndra soils is included in most soil classifications.
EA-PS. Nikiforoff: Introduction
Glinka’s view is hardly justifiable. “Tundra soils” are not less indi–
vidual than their antipodes, the “tropical soils.” They develop and function
under specific conditions which do not exists in other natural zones. Their
dynamics are fundamentally different from those of the soils of any other
genetic type, and this, indeed, is the principal criterion for differentiation
between type, and this, indeed, is the principal criterion for differentiation
between various genetic groups of soils.
The tundra soils develop under conditions of very low biological pressure,
low temperature, and generally rather excessive moisture. These three principal
factors impart to the tundra soils their peculiar characteristics. Virtually
all tundra soils are generally cold, poorly aerated, and consequently poorly
if at all oxidized, and little affected by organisms.
Biological Factors of Soil Formation
Tundra vegetation is scant is number of species and volume of vegetable
matter per given area. Vegetative periods are very short, generally cool,
with occasional frost especially at the beginning and the later part of the
season, and characterized by continuous isolation which, according to Grigoriev,
is relatively rich is harmful ultraviolent rays. The soil conditions for plant
growth are equally poor. Due to perennial frost in the ground, the soils are
generally much too cold for a normal development of most plants. Only a thin
upper layer having a thickness of just a few inches may acquire for a short
time a fairly high temperature and even overheated in exposed spots. The
subsoil below this thin layer usually is saturated with cold melt water which
hampers oxidation of the soil material. In particular, most of the free iron
in tundra soils remains in the form of harmful peroxides. Again, roots are
broken by a thorough freezing of the soil
s
in winter with formation of numerous
EA-PS. Nikiforoff: Introduction
thin layers and lenses of pure ice interbedded with mineral soil.
Few plants are able to adapt themselves to such adverse conditions and
even their growth is very slow. It has been reported that the annual shoots of
the arctic dwarf willow hardly exceed an inch in length, so that only a few
new leaves are formed.
The commonest plants in the tundra are lichens and mosses which do not form
roots. Roots of other plants, including arctic shrubs such a dwarf polar birch,
willow, and ledum, an a few herbs, mostly sedges, do not penetrate the soil to
any considerable depth. Grigoriev states that “as a rule, roots do not extend
deeper than 10 to 20 centimeters. Only the roots of dwarf birch reach a depth
of 30 to 35 centimeters, and
[:
]
occasionally 60 centimeters. Hence, the roots
of tundra plants are distributed largely in the peaty layer; at the beginning
of the vegetative period the active suckling new roots are predominantly in
this layer.” A similar statement is made by Gorodkov, who points out that
“roots and creeping stems of shrubs are able to distribute only in a peaty
sod, hardly extending into the soil. One may easily pull out such a shrub by
hand.”
Under such conditions extraction of mineral elements from the deeper parts
of the soil and accumulation of this material in the upper soil horizon — an
essential feature of soil formation in the lower latitudes — proceed in the
tundra at the exceedingly low rate. Precise data on the amount of annual produc–
tion of new vegetable matter per given area are not available, but it hardly
can be doubted that such production is meager. Thus the normal soil-to-plant–
to-soil pedogenic cycles in the tundra affect only minute quantities of elements
and even these are mobilized largely from the very think uppermost soil horizon.
EA-PS. Nikiforoff: Introduction
Liverovski points out that the exchange capacity of various arctic soils
is fairly high and that, due to the absence of strong leaching, the degree of
saturation of these soils usually is very high also. In fact, the few analyses
which have been made show the absence of exchangeable hydrogen. It follows
that free bases are present in quantities sufficient for saturation of the soil.
These bases, however, are largely inert because of very small requirement.
for them by the scant and inexacting tundra vegetation.
Because a meager growth of the sparse tundra plants, the annual depositions
of organic resid
e
ues on the surface of tundra soils are very small indeed in
comparison with those received by the soils of the temperate belt. Strong
winter winds sweep away a large part of these residues together with the dust
and dry snow. Leffingwell states that “such forms of vegetation as occur upon
the
t
^
T
^
undra are broken off and carried by the wind to great distance, but the
total amount of such material must be very small.”
Decomposition of the remaining part of organic residues also is slow. The
shortness of the warm season combined with poor aeration and prevailingly low
temperature of the soil hinder development of the microbial population and reduce
biochemical activity in tundra soils to a very low level. Hence, throughout
the tundra, in spite of meager growth of plants, there is a tendency for the
formation on the surface of the soil of a fibrous peaty mat, usually interwoven
by the roots of shrubs. In the Arctic proper this peaty mat is rarely more than
a few inches thick and is act continuous over large areas. Usually it forms
in relatively depressed places, which may catch some drifting snow in winter,
and is absent on exposed elevated spots. Toward the boundary of subarctic and
wooded tundras and throughout these tundras the thickness and continuity of the
peaty cover increase.
EA-PS. Nikiforoff: Introduction
A meager production of vegetable matter in the tundra indicates a very
low rate of assimilation of atmospheric carbon dioxide by plants. In the same
way, slow decomposition of the scant organic residues results in a very low
rate of emission of this gas from the soil into the air. These complementary
processes are in accord with a conspicuously low content of carbon dioxide in
the air in high latitudes. This content
of carbon dioride in th
is only a
little more than half that in the middle and lower latitudes.
Scarcity of microbial population of the tundra soils is responsible
also for a very low rate of fixation of free nitrogen. Moreover, due to the
prevailing poor aeration of these oils, the existing population consists
predominantly of anacrobic organisms, among which are only few nitrifying
species but a greater number
o
of denitrifying ones. Hence, as a rule, the
nitrogen content of most tundra soils is extremely low.
The peaty layer, which is called
trunda
in Siberia, overlies the mineral
substratum, which is gray and in places mottled with rusty
strains
stains. The
boundary between the two layers usually is sharp, especially if the lower
layer is clayey. Few roots extend from the upper layer into the lower and,
in all likelihood, little exchange of material between the two layers is
taking place. The mineral substratum is practically unaffected by biochemical
processes and, usually, is not differentiated into various horizons, the formation
of which is controlled by these factors.
EA-PS. Nikiforoff: Introduction
Thermal Conditions of Soil Formation
Formation of tundra soils takes place at a very low temperature which
slackens all chemical and especially biochemical processes. Virtually all
biochemical activity cease at a temperature just below the freezing point; most
chemical processes also come practically to a standstill at this temperature.
During the long arctic winter most tundra soils are solidly frozen and,
so to say, chemically dormant. Their defrosting in spring and in the cool
and short summer is slow and rather ineffective. Since the geothermal gradient
in the Arctic is aggraded to a temperature several degrees below freezing point
and crosses this point at considerable depth, the flow of phreatic heat does
not
[:
]
enhance the seasonal warming of these soils. Summer defrosting of the
tundra soils is due entirely to the inflow of vadose heat, the rate of which
is not high. Grigoriev states that at 73° N.
L
^
l
^
attitude the effective radiation
from May 1 through October 1 amounts to about 50,000 calories per square
centimeter of horizontal surface. About four-fifths of this amount is sent
back to the air as long-wave terrestrial radiation. In the lower latitudes a
large part of this radiation is absorbed in the air, especially by water vapor,
and turned again toward the earth. In the Arctic, however, the content of
water vapor in the cold polar air is very low. The content of carbon dioxide
also is low, as has been mentioned above. These conditions drastically decrease
absorption of terrestrial radiation in the air so that the heat emitted from
the ground is large
^
l
^
y lost to space without much thermal effect on the soil.
The remaining part of the heat generated by radiant energy, which on the aver–
age amounts to about 10,000 calories per square centimeter per year, is largely
consumed in the melting of snow and ground ice. It has been calculated that
EA-PS. Nikiforoff: Introduction
defrosting to the depth of one meter of a soil with moisture content of 0.3
gram of water per cubic centimeter required 2,400 calories per each square centi–
meter of surface. Moisture content of many tundra soils is considerably higher
than this and their defrosting requires more heat for melting of ground ice.
Thus probably not more than about 2,000 calories per square centimeter are left
for warning the soil and raising its temperature above freezing point.
Depending upon steepness and direction of the slope, character of vegeta–
tion, mechanical composition, porosity and moisture of the soil, specific heat,
and thermoconductivity of its mineral material, as well as various other condi–
tions, tundra soils thaw to a maximum depth of only a few feet. In many places
this depth is less than a foot. Defrosting lasts only a few months, on the
average
,
probably not more than about a hundred days a year. The duration
of defrosting, of course, decreases with
dcp
depth so that only the upper foot
or two remains free of frost throughout the warm season.
The proximity of the frozen subsoil, which steadily consumes the inflow–
ing heat for melting of ground ice, prevents the rise of temperature for more
than a few degrees above the freezing point even in this thin layer so that only
the uppermost few inches of it may
[:
]
acquire fairly high temperature and even
be overheated on bare elevated spots.
Such are the limits of space and time within which the strongly
sh
subdued
chemical processes take place in tundra soils. The relative ineffectiveness
of the processes in arctic environment is particularly conspicuous in the
general character of weathering, which is decidedly dominated by physical processes.
Disintegration of rocks in the tundra, especially by frost action, is quite strong,
whereas chemical decomposition even of the less resistant minerals is very slow.
Hence, the resultant products are as a rule of very coarse texture with an ex–
ceedingly low content of residual clay.
EA-PS. Nikiforoff: Introduction
The low rate of chemical decay of rock debris and formation of residual
clay does not mean, however, that tundra soils are predominantly coarse and
skeletal. Large parts of the arctic land are formed by broad marine terraces
underlain by marine sediments including marine clays. River terraces and ex–
tensive deltas of great rivers which cross the tundra and empty into the arctic
seas are built of fine alluvium brought down from warmer regions outside of the
arctic belt. Other enormous areas are covered by glacial moraines. A great
many tundra soils are developed from these various preweathered materials and
are characterized by a very fine mechanical composition. Large areas of the
Siberian Arctic are
f
referred to as “clayey tundras;” in fact, clayey tundra
soils very likely are more common than sandy ones, especially through the
arctic coastal lowlands.
Hydrologic Regime of Tundra Soils
The third conspicuous feather of the tundra type of soil formation is that,
in spite of very low precipitation, it takes place under a condition of excessive
moisture. Throughout a large part of the Arctic the mean annual rainfall is
less than ten inches; large areas have less than five inches. Nevertheless
most tundra soils are practically saturated throughout the periods of their
defrosting. Two factors are chiefly responsible for such a condition — im–
permeability of the frozen subsoil and very low rate of evaporation. Inci–
dentally, the last factor is also responsible for the very low content of water
vapor in the air and, consequently, the loss of a large part of the heat emitted
by terrestrial radiation.
In the absence of efficient evaporation the small quantity of rain water,
which comes in rather frequent summer drizzles, and the melt water formed by the
EA-PS. Nikiforoff: Introduction
defrosting of the soil remains in the defrosted layer and accumulates on the
surface of the frozen substratum. The discharge of melt water by surface runoff
is generally small, due in part to inadequate dissection of the land by the
drainage channels and in part to a peculiar tundra microrelief which will be
described later.
Again, only the uppermost layer of the defrosted soil, having a thickness
of only a few inches, dries thoroughly. On elevated spots which are barely
covered by vegetation it may even be so desiccated that shallow rooted plants
wilt and die. Such spots, ranging in diameter from several feet to several
rods, are a common feature of the tundra landscape. Because of their relative
elevation they are practically denuded of snow by wind, and are subject to the
full fury of arctic winter. The soil of these spots freezes faster and deeper
and its temperature drops lower than in nearby depressions in which the snow
accumulates. Also, in summer, the soil on these spots thaws faster and to a
greater depth and its upper layer is subject to the sporadic overheating and
desiccation that kills shallow-rooted vegetation. Deep-rooted plants which
would reach the waterlogged layer just a few inches below to not survive be–
cause in freezing during winter thin lenses of ice are formed in the soil and
break the rootlets. All these various conditions lead to a permanent baldness
of such spots and to the development of a typical mosaic of the “tundra complex.”
Waterlogging of tundra soils during the period of defrosting prevents their
aeration and normal oxidation as well as the development of aerobic biochemical
activity. Under much conditions, the iron compounds in tundra soils remain
largely in the peroxide from which imparts to these soils a conspicuous dull gray,
sometimes bluish gray color, in place mottled with rusty stains.
EA-PS. Nikiforoff: Introduction
This color is a common characteristic of most tundra soils. It is particu–
larly strong in the peaty or boggy tundras, the soils of which arereferred to
as gley-peaty or gley-bog soils. Only decidedly sandy tundra soils and especially
those in hilly regions, for example those on terminal moraines, may be free of
waterlogging and gley formation. Generally these soils thaw to a greater depth,
are somewhat better oxidized, and are somewhat warmer in summer than heavier soils.
Impossibility of percolation of vadose water through the perennially frozen
subsoil and waterlogging to within a few inches from the surface, and in low
spots completely, prevent leaching of tundra soils as well as redistribution between
the various soil horizons of finely divided material by its transportation in
suspension. Therefore, neither eluvial nor illuvial horizon can be formed.
Again, exceptions are possible only in sandy soils in which some traces of weak
podsolization have been described by various authors (Liverovski, Grigoriev,
Gorodkov, and others). Such soils are called the pygmy tundra podsols.
Due to lack of leaching, even minute quantities of various soluble compounds
which may be set free by the strongly subdued chemical weathering, are not
readily if at all removed from the soil and, occasionally, may even be lifted
to the surface by capillary pull. For example, the presence of carbonates and
various other salts on and near the surface of the soils of bare spots is not
uncommon. Liverovski states that these soils might acquire the character of
peculiar tundra
solonchaks
(saline soils). Salinization even weak as it may
be, however, is not an essential characteristic of the tundra-type soils forma–
tion in general. Most tundra soils are not saline in spite of the lack of
leaching. Nevertheless, even a sporadic local occurrence of such soils shows
the influence of perennial freezing of the ground upon the dynamics of various
soluble compounds in tundra soils.
EA-PS. Nikiforoff: Introduction
Solifluction
Waterlogging of tundra soils is accompanied by solifluction wherever relief
allows the development of sufficient hydrostatic pressure. Although periods of
annual defrosting of tundra soils are short, periods in which solifluction
occurs are still shorter. Solifluction begins when the soil is thawed to a
sufficient depth and enough water is accumulated in the lower part of the defrosted
layer to render it fluid. Usually such a condition is reached in early summer.
The process slows down and finally ends early in fall as soon as new freezing of
the soil from the surface cuts short the supply of melt water and builds numerous
obstructions in the way of subsoil mud-flows.
Solifluction affects especially clayey and loamy soils in which clay and
other finely divided material serves as a sort of lubricant. It is less common
with sandy soils, which generally are drier than soils of finer texture.
Fluid mud under the relatively dry and solid crust of surface soil probably
never moves in a sheet because of the unevenness of the frozen surface over which
it slides. The rate of defrosting of tundra soils varies from place to place.
Minute changes in character of the surface, such as its microrelief, differences
in density and composition of vegetation, or in thickness of moss or peat cover,
strongly affect the speed of thawing of the soil and lead to the development
of a subterranean microrelief of the surface of the frozen subsoil. The differ–
ence in depth of thaw may be more than two feet within a linear distance of
only a few feet.
Hence the surface of the frozen ground consists of numerous mounds and
little ridges separated by hollows, miniature troughs, and other depressions
throughout periods of defrosting. The
[:
]
subterranean microrelief may or may
EA-PS. Nikiforoff: Introduction
not correspond to the microrelief of the surface of the soil. For example,
the bald mounds or other bare spots are defrosted faster and to a greater depth
than the adjacent depressions which are covered with moss or a thin layer of
peat. Thus, not uncommonly hollows on the frozen subsurface are formed under
relatively elevated portions of the land surface.
Melt water accumulates in these hollows in the subsoil and begins to move
through the labyrinth of interconnected shallow channels which may narrow in some
places and widen in others. The layers of fluid mud (
plyvun
or quick-mud) must
acquire a certain thickness in order to overcome friction with the surfaces be–
tween which it has to move and develop momentum. It slides easily over the
smooth frozen surface but it has to tear itself away from the overlaying sod
or crust or dry soil unless it carries this material along.
The velocity of mud-flows changes with slope, moisture content, thickness
of the fluid layer, character of the subterranean microrelief, and various other
factors, and apparently never is uniform throughout any considerable area. Hence
the hydrostatic pressure of solifluction drops in certain
[:
]
places and rises
in others. Wherever it rises it may become strong enough to lift the overlying
crust of dry soil and bulge the soil up to form new mounds and ridges. If the
crust or sod is not strong or elastic enough to bend, it may break and quick-mud
pours out onto the surface.
With the upward lifting of the sod, hydrostatic pressure under the new mounds
subsides, and the flow of mud through this channel may stop altogether, forcing
the mud advancing from the higher areas to seek other outlets or to form other
similar mounds or ridges. Bulging up of the mounds enhances evaporation from the
surface the thus drying of the soil, so that the quick-mud under the mound thickness
and the local swelling becomes temporarily stabilized.
EA-PS. Nikiforoff: Introduction
During winter, however, new mounds are subject to the usual hazards of
arctic environment. Winds sweep away the snow, leaving the mounds unprotected
against frost. In summer tops may suffer from overheating and desiccation.
All these various factors rapidly kill vegetation, destroy the remnants of
meager sod, and render the mounds bald. Then, by the combined efforts of blow–
ing asunder, slurring with melting snow and ice, and erosion by rains, the
mounds are gradually leveled, again occupied by lichens, moss, and other plants,
and finally
[:
]
obliterated until solifluction bulges up another swelling thus
starting the next cycle. Such, in general, are the dynamics of tundra micro–
relief, brought about and maintained by solifluction, the general trend of which
is toward movement downslope of the loosened-by-defrosting soild material.
Frost Blisters and Involution
Solifluction is essentially a summertime process. As pointed out above, it
ceases early in the fall and is rejunvenated the following summer. In winter
tundra soils are affected by different processes. Freezing of tundra soils in
fall and early winter is not more uniform than their defrosting in summer. De–
pending upon various local conditions, the soils freeze at certain points much
faster and to a greater
^
^
depth than in other places. Therefore, the inward advancing
frost-front acquires its own microrelief facing toward the sub
e
terranean surface
microrelief of the perennially frozen ground. In place where freezing is
especially fast, the fall freezing may advance to the depth of maximum summer
thaw, so that the interfacing frost-fronts meet and the soil becomes thoroughly
frozen from the surface to the bottom of the perennially frozen layer. In these
places the external frozen crust is fastened to the perennially frozen substratum.
EA-PS. Nikiforoff: Introduction
Such a meeting of frozen layers, however, does not take place simultaneously
throughout the area and in many places probably does not occur at all. The
frost-front, advancing from the surface downward, eventually reaches the layer
of soil saturated with summer melt water and
[:
]
seals this water between the
two solidly frozen surfaces. Water or fluid mud trapped between the frozen layers
is confined to the maze of flattened interconnected pools spreading between
points at which the soil is solidly frozen to indefinite depth. Thickness of
this unfrozen layer ranges from a fraction of an inch in some places to more
than a foot and probably even to several feet in others. Some pools may have an
area of a few tens of square feet, whereas others may occupy more than an acre.
Again, some pools may be completely closed, whereas others may be interconnected
over fairly large areas.
Sometimes during the winter the temperature at the depth of this trapped
water decreases below freezing, but feezing of the water is impeded by lack of
space for expansion. Therefore, formation of any amount of ice in these layers
is accompanied by a rise of frost-generated hydrostatic pressure. It may
increase to an equivalent of several tens of atmospheres. Since the underlying
frozen ground is virtually indestructible, all this pressure is directed against
the overlying crust of frozen soil. Sooner or later the pressure rises to a
point high enough to overcome the resistance of the crust. At this moment the
soil can be split horizontally and its upper part may be lifted enough to allow
the trapped water to freeze the form a layer of ice ranging in thickness from less
than an inch
t
to several feet.
The strength of the crust of frozen soil, however, varies from place to
place, and, naturally, and crust bends or breaks first at the points of its
EA-PS. Nikiforoff: Introduction
greatest weakness. At these points the upper crust is torn away from the sub–
soil and begins to bulge up as an immense frost blister. Such blisters may
rise more than
l
ten feet and have a base considerably more than a hundred feet
in diameter. If the swelling provides enough room, then all the water in it
freezes and ice fills the cavern in the form of large lenses. Otherwise, the
blister bursts open with a loud report, and the excess water and mud pour out
and freeze on the surface. The remaining part of the water inside the cavern
freezes.
Formation of blisters is, indeed, the most spectacular manifestation of
the process. Perhaps more commonly the frost-generated hydrostatic pressu
^
r
^
e is
released less dramatically and, so to say, piecemeal. A slight bulging up here
and there, sometimes for an inch or a few inches at a time, is accompanied by
formation of thin layers or lenses of ice. Very commonly these layers of ice are
only a small fraction of an inch thick and are formed in series, interbedded
with soil.
If the soil is porous or broken by cracks due to contraction on chilling,
then water is squeezed to the surface where it freezes layer by layer to form
external icing or
taryns
. This process is most common in stream valleys where
a single icing may cover several square miles and the ice may be several tens
of feet thick.
As has been pointed out, individual pools of fluid mud and water, entrapped
by winter freezing, may be interconnected. Differences in intensity of freezing,
may be interconnected. Differences in intensity of freezing and, consequently,
in hydrostatic pressure at various parts of the subsurface labyrinth create
stresses tending to maintain an equilibrium throughout the system. The release
of hydrostatic pressure at particular points, whether by the break of a blister
EA-PS. Nikiforoff: Introduction
or by bulging of the upper crust, directs the forced flows toward these points
from surrounding areas.
Fluid mud may be carried and pushed by these stresses one way or another un–
til it becomes frozen. It is forced into cracks and other cavities, including
caverns of large and small frost blisters; or it may be ejected onto the surface,
sometimes forming miniature and volcanoes. Thus the material of inner soil
horizons is displaced horizontally and vertically.
Most of the ice layers, wedges, and lenses melt during the summer, the
blisters collapse, and the soil subsides till the following winter when the
same processes are repeated. Repetition of such vertical movements year after
year leads to a gradual infiltration of finely divided material, such as clay
and silt, into the lower horizons and accumulation of coarse material on the
surface. On bare spots such an accumulation is enhanced by wind erosion which
sweeps the remaining fine material away leaving in places nothing but stones
on the surface of the soil. This common process is essentially similar to the
formation of “desert pavement” (Leffingwell, Grigoriev, Liverovski, and others).
Since wind erosion in tundra affects especially the relatively elevated areas,
such as the tops of mounds and ridges that are unprotected by vegetation, the
distribution of the stony armor usually is very uneven (stony rings, stony
strips, and so on).
All these various processes are a part of the dynamics of tundra soils,
and they impart of these soils peculiar morphological
d
characteristics.
Grigoriev points out that the soil horizon may display a somewhat chaotic ar–
rangement. Especially conspicuous are the characteristics which result from
horizontal displacements of material in the middle and lower horizons. These
displacements break the vertical unity of the soil profiles. Either by soli-
EA-PS. Nikiforoff: Introduction
fluction or by frost-generated hydrostatic pres
^
s
^
ure horizons may be removed in
their entirely to be replaced by foreign material pressured into the evacuated
space (involution).
Due to these various horizontal and vertical movements repeated year after
year — peculiar processes, some of which affect the soil in summer and the
others in winter — the profiles of most, if not all, tundra soils are mechanically
restless.
Tundra Complexes
The intensity of the several processes, some of which have been described,
varies from place to place. Their relative strength is determined by various
regional and local conditions. Thus solifluction does not take place in topo–
graphically featureless flat areas. It is particularly strong in sloping areas
in which the summer thaw of the soil is deep enough for an accumulation of melt
water in quantities sufficient for rendering the subsoil fluid. Such conditions
are more common in subarctic tundras and even farther south of the tundra zone,
in parts of the taiga belt affected by perennial ground frost. In the Far
North defrosting of the ground does not extend deep enough to provide physical
instability of the layer in which forces of solifluction would develop a
necessary momentum.
Horizontal splitting of the soil by ice lenses and frost blistering may
take place throughout the Arctic; but, again, if the upper frozen crust is
relatively thin, it then yields and cracks or bends before hydrostatic pressure
in the entrapped fluid layer can rise very high. Hence, in the Arctic proper,
where average depth of annual defrosting of tundra soil does not exceed a foot
or two, formation of frost blisters is less common and blisters that do form
EA-PS. Nikiforoff: Introduction
are smaller than, say, those in wooded areas.
In the Far North, especially in the subpolar deserts, somewhat different
processes are taking place. Practically all explorers of the Arctic point
out a peculiar mosaic of the surface of arctic tundra. Several types or
patterns of this mosaic have been described under the name of tetragonal and
polygonal tundras, spotted tundras, mound tundras, and others. It appears
likely that most, if not all, these various types of arctic tundra develop
through winter frost action which breaks the surface layer of the ground into
large and small roughly polygonal blocks.
Although formation of frost cracks was first pointed out more than a
century ago (Figurin, Middendorff), Bunge probably was the first to describe it
in considerable detail and to suggest a plausible explanation of the phenomenon
and its impact upon the tundra ladscape. A few decades later, Bunge’s observa–
tions and hypothesis were confirmed by Leffingwell who independently arrived
at much the same conclusions. Recently the literature on this subject
[:
]
has been greatly expanded; but little new has been added to the original ideas
of Bunge and Leffingwell.
One of the commonest patterns of arctic tundra is formed by irregular polygons
with edges slightly elevated above the flat middle parts in the shape of miniature
gently sloping ridges. Each polygon is surrounded by its own ridges, so that
between ridges encircling neighboring polygons there is a furrow or trough
along which runs a crack extending to a considerable
[:
]
depth.
Cracking takes place during winter, presumably due to contraction of the
frozen ground on chilling. Leffingwell states that this cracking is accompanied
by loud reports and shocks which may be strong enough to shatter dishes in
dwellings.
EA-PS. Nikiforoff: Introduction
Precise data as to depth of cracking are not available. It appears, how–
ever, that if the original cracking is due to contradiction of the ground, then,
obviously, it cannot extend below the level at which annual changes in tempera–
ture are too small for the necessary changes in volume of the ground. It is
assumed that frost cracks may extend several feet below the depth of maximum
summer thawing of the soil. At the surface, cracks may be more than an inch
wide, their width decreasing with depth to the vanishing point.
In the horizontal plane, the cracks are oriented in either a conspicuous
tetragonal or, more commonly, polygonal pattern. The former is formed by more
or less parallel cracks which run in two different directions intersecting each
other at about right angles. Thus, these cracks divide the soil roughly into
rectangular blocks (the checker-board pattern).
It has been observed that the rectangular pattern of cracks develops where
one series of parallel cracks follows the direction of a bank, lake or stream
shore, terrace edge, or some other similar natural boundary line. More commonly
the cracks radiate in three different directions, from more or less proportionally
distributed points, and join to form a honeycomb or mud-crack pattern dividing
the surface into roughly hexagonal or pentagonal blocks.
Individual polygons vary in size from area to area. Within a single area,
a
however, size range is rather narrow. Leffingwell states that the average size
of blocks in the region of his study is about sixteen yards. According to Taber,
the polygons range from 35 to 60 feet in diameter; whereas Bungs points out that
large polygons usually are broken into much smaller units by smaller cracks.
In warm seasons the cracks are filled with melt or rain water which eventually
freezes to form “ice wedges” that enlarge the original fissures. It is assumed
EA-PS. Nikiforoff: Introduction
that, once formed, the crack serves as a plane of weakness of tensile strains.
Thus the same cracks reopen year after year, each time receiving more water, with
more ice forming each following winter. Hence, formation of ice wedges, pre–
sumably, leads to progressive lateral and vertical enlargement of cracks and
exerts strong pressure upon their walls. This, in turn, should force the ground
on the peripheries of the polygons to bulge and form ridges. Such ridges may
be several feet wide and more than a foot higher than the floor of the encircled
depression. The depression usually is devoid of vegetation, rather boggy, and
may be occupied by a shallow pool in summer.
The polygonal tundra is typical of low and generally boggy coastal flats,
broad marine and stream terraces, and other level areas in which solifluction
does not take place.
Surface configuration of the mound tundra is different. Here the
[:
]
middle parts of the polygons are elevated and surrounded by narrow hollows or
troughs forming a honeycomb network marking the courses of frost cracks. At
points where the cracks branch, the hollows usually are wider and somewhat
deeper than between these points. Therefore, the angles of the perimeters of
polygons usually are mor or less rounded. The smaller the individual polygons,
the more pronounced is their rounded shape, although the pattern of the cracks
themselves remains
pl
polygonal. Elev
l
ation of middle parts of the blocks above
surrounding depressions ranges from about a foot to more than two feet. Large
blocks may have flattened tops, whereas smaller ones are characterized by gently
rounded vertical profi
^
l
^
es.
It is likely that bulging up of these mounds is due largely to pressure from
the periphery exerted by the ice wedges growing in frost cracks. In this case,
however, the pressure must be transmitted farther from the walls of cracks toward
EA-PS. Nikiforoff: Introduction
the center of the block, thus forcing the ground upward in the middle parts of
the polygon rather than at its edges. Again, if the size of polygons is small,
then the peripheral ridges might merge to form a general mound instead of a ring
around a middle depression. Slumping of the edge of open cracks should cause
some widening of furrows between mounds as well as rounding of the mounds them–
selves.
Wherever solifluction, frost blistering, frost cracking, or any other simi–
lar process takes place the surface of the tundra acquires a conspicuous micro–
relief. The commonest type of tundra microrelief is represented by small, more
or less rounded mounded rising a foot or two above the surrounding (and usually
boggy) depressions. Such microrelief might develop due to solifluction or frost
cracking. Mounts formed by solifluction are generally larger, more irregular
in shape, and less densely distributed throughout the area than mounds that are
formed by
gu
bulging up of the polygons. Mounds of the latter type range in
diameter from several feet to a few tens of feet and usually are set very thickly,
with only narrow furrows between; whereas mounds built by solifluction may be
several times larger and may be separated by wider boggy areas.
Irrespective of the mode of formation, the mounds usually are covered by
very scant vegetation and not uncommonly are devoid of any vegetation except
for some lichens. The tundra vegetation — mosses, sedges, and shrubbery —
crowds in hollows where snow gives it some protection against the rigors of
arctic winter. Not uncommonly, depressions between mounds are crowded by fairly
high compact tufts (tussocks) formed by bunch sedges. Other depressions may
be lined with a thin layer of peat. In a typical arctic mound tundra, vegetation
confined to the furrows and edges of cracks forms a network of garlands enmeshing
the elevated patches of bare ground.
EA-PS. Nikiforoff: Introduction
The depressed polygons (tetragons, hexagons, and others) represent the
other conspicuous kind of microrelief of the arctic tundras. Here the depressed
middle parts of the polygons usually are devoid of vegetation, which is confined
to the edge of frost cracks and furrows between the peripheral ridges encircl–
ing the adjacent depressions. Dranitsin described this kind of microrelief as
a “medallion tundra.”
Like the tundra soils themselves, tundra microrelief is restless. Each year
new mounds bulge up here and there, while some older ones are flattened and dis–
appear under the moss.
Due to uneven distribution of vegetation and wide differences in thermal and
hydrologic conditions between the elevated and depressed areas, the general
character of tundra soils changes sharply within very short distances. In fact,
most of the tundra is occupied by several different soils which are so distributed
in relation to one another that no one dominates the landscape or occupies
solidly any considerable area, but all collectively form a sort of soil tissue
commonly referred to as a “soil complex,” or, more specifically, “a topographic
soil complex.”
The distribution of various components of a topographic soil complex is
determined by the microrelief. The most contrasting members of the topographic
soil complex or its “end members” are the soil occupying the better drained
elevated spots and a different soil which forms in boggy depressions. The
commonest
d
tundra soil complexes are those which occupy the mound and polygonal
tundras.
EA-PS. Nikiforoff: Introduction
Bibliography
1. Berg, L. S.
Priroda
. (In Russian.) English translation:
Natural Regions
of the USSR
. N.Y., Macmillan, 1950.
2. Bunge, A. von. “Naturhistorische Beobachtungen und Fahrten im Lena Delta.”
(In German.) St. Petersburg, Academy of Science,
Bull
. vol.29,
pp.422-75, 1884.
3. Gerasimov, I. P., and Markov, K. K.
Glacial Period in the Territory of the
USSR
. (In Russian with English summary.) Moscow-Leningrad, Acad.
Sci. U.S.S.R., 1939.
4. Grigoriev, A. A.
Subarctic
. (In Russian.) Moscow-Leningrad, Acad. Sci. U.S.S.
R., 1946.
5. Leffingwell, E. deK. “The Canning River Region, Northern Alaska,” U.S.
Geol.Surv.,
Prof.Paper
109. 1919.
6. Liverovski, Y.A.
Soils of the Boggy Tundra Belt.
(In Russian.) Moscow–
Leningrad, Acad. Sci. U.S.S.R., 1937.
7. Lukashev, K. I. “Mound formation as a manifestation of the tension in the
perennially frozen soils.” (In Russian.) University of Leningrad,
Univ.,
Annals
,
pp.
vol.3, pp.147-58, 1936.
8. Middendroff, A. T. von.
Sibirische Reise
. Acad. Sci. St. Petersburg,
Acad. Sci., 1848-1859.
9. Nikiforoff, C. C. “On certain dynamic processes in the soils of perennially
frozen regions. (In Russian and French.)
Pochvovedenie
, no.2,
pp.50-74, 1912.
10. ----. “The perpetually frozen subsoil of Siberia,”
Soil Sciences,
vol.26, pp.
61-81, 1928.
11. Obruchev, S. V. “Solifluction terraces and their origin, based on survey in
the Chukotsk region.” (In Russian.)
Problemy Arktiki
, no.3, pp.
27-48; no.4, pp.57-83, Leningrad, 1937.
12. Porsild, A. E. “Earth mounds in unglaciated northwestern America,”
Geog.Rev.
,
vol.28, pp.45-58, 1938.
13. Sharp. R. P. “Ground-ice mounds in Tundra,”
Geog.Rev
., vol.32, pp.417-23, 1942.
14. Stefansson, V. “Ground ice in northern Alaska,” Am. Geog.Soc.
Bull
, vol.42,
pp.337-45, 1910.
15. ----. “Underground ice sheets of the Arctic Tundra,” Am.Geog.Soc.
Bull
, vol.
40, pp.176-77, 1908.
EA-PS. Nikiforoff: Introduction
16. Sumgin, M. I.
Ever Frozen Soils in the U.S.S.R.
(In Russian.) Moscow,
Acad. Sci. U.S.S.R., Moscow, 1937.
17. ---- et al.
General Cryopedology
. (In Russian.) Moscow-Leningrad, Acad.
Sci. U.S.S.R., 1940.
18. Suslov, S. P.
Physical Geography of the U.S.S.R.
(In Russian.) State Peda–
geologic Publication. Moscow-Leningrad, 1947.
19. Taber, S. “Frost heaving,”
Journ.Geol
., Vol.37, pp.428-44, 1929.
20. ----. “Perennially frozen ground in Alaska; its origin and history,” Geol.
Soc. of Am.
Bull.
,
[:
]
vol.54, pp.1433-1548, 1943.
21. ----. “Surface heaving caused by segregation of water forming ice crystals,”
Eng. News-Record.
vol.81, pp.683-84, 1918.
22. Tsitovich, N.A., and Sumgin, M. I.
Principles of Mechanics of Frozen Grounds.
(In Russian.) Moscow, Acad. Sci. U.S.S.R., 1937.
23. Tyrell, J. B. “Crystophenes of buried sheets of ice in the tundra of North
America,”
Journ.Geol
., vol.12, pp.232-36, 1904.
C. C. Nikiforoff
Soils of Alaska
EA-Plant Sciences
(Iver J. Nygard and A. C. Orvedal)
SOILS OF ALASKA
CONTENTS
|
|
Page
|
|
Soil-Forming Factors
|
3
|
|
Climate
|
3
|
|
Vegetation
|
4
|
|
Parent material
|
5
|
|
Relief
|
5
|
|
Age
|
6
|
|
Great Soil Groups
|
6
|
|
Tundra Soils
|
7
|
|
Tundra with Permafrost
|
9
|
|
Tundra without Permafrost
|
10
|
|
Podsols
|
12
|
|
Subarctic Brown Forest Soils
|
14
|
|
Bog Soils
|
17
|
|
Half-Bog
|
18
|
|
Groundwater Podsol
|
20
|
|
Mountain Tundra
|
21
|
|
Alpine-Meadow Soils
|
23
|
|
Alluvial Soils
|
24
|
|
Lithosols and Regosols
|
25
|
|
Distribution of Soils
|
25
|
|
Map Unit 1
|
25
|
|
Map Unit 2
|
26
|
|
Map Unit 3
|
27
|
|
Map Unit 4
|
27
|
|
Map Unit 5
|
28
|
|
Bibliography
|
29
|
EA-Plant Sciences
(Iver J. Nygard and A. C. Orvedal)
PHOTOGRAPHIC ILLUSTRATIONS
With the manuscript of this article, the authors submitted 8
photographs and 1 colored map for possible use as illustrations. Because
of the high cost of reproducing them as halftones in the printed volume,
only a small proportion of the photographs and maps submitted by contri–
butors to
Encyclopedia Arctica
can be used, at most one or two with each
paper; in some cases none. The number and selection must be determined
later by the publisher and editors of
Encyclopedia Arctica
. Meantime
all photographs and maps are being held at The Stefansson Library.
EA-Plant Sciences
(Iver J. Nygard and A. C. Orvedal)
SOILS OF ALASKA
The soils of Alaska — a vast area of 586,400 square miles — are
comparatively unknown and await further studies, both exploratory and
detailed. Exploratory surveys are needed to obtain a general knowledge
of the soils of the Territory as a whole; detailed surveys should follow
to provide precise information of specific localities, especially of
those considered potentially useful for crops and pasture. This article
is based upon recent information derived from field studies, laboratory
examinations, and a review and interpretation of other geographic and
soil researches in a monograph (3), in press in 1950, by Dr. Charles E.
Kellogg and Dr. Iver J. Nygard, soil scientists in the U.S. Department
of Agriculture.
During the summer of 1946, exploratory investigations of the agricul–
tural research needs of Alaska (4) were made by a group of technical
employees of the Department of Agriculture. The field of soil science
was represented by Dr. Charles E. Kellogg and Dr. Iver J. Nygard. In 1948
a second trip was made by Dr. Nygard and Dr. Allan Mick, the latter of whom
is now in charge of soil research for the Alaska Agricultural Experiment
Station, organized that year. Members of the U.S. Geological Survey have
been most helpful in the preparation of this paper, especially in compliling
EA-PS. Nygard and Orvedal: Soils of Alaska
the soil association map.
The main body of Alaska lies approximately between latitudes 60° and
71° N. and longitudes 141° and 165° W. Only about one-third of it is
situated north of the Arctic Circle, and still less is truly arctic in
type. From the main body, two long arms extend far below the Arctic Circle,
one comprising southeastern Alaska, and the other the Alaska Peninsula from
which the Aleutian Islands continue as a thin chain into the Eastern
Hemisphere.
Outside of the Matanuska Valley, and to a lesser extent the Fairbanks
vicinity, exceedingly little land is used for agriculture. Consequently,
there is a lack of farm-management experience for most of the many different
kinds of soils in the Territory.
Any estimate of the amount of land suitable for farming in Alaska ought
to rest upon several considerations. Important among these are: (
1
) the
location and size of land areas with the favorable combinations of soil
and climate that are needed for crop production, and (
2
) the present state
of agricultural arts and research with regard to Alaskan conditions. A
knowledge of the response of soils to management is needed. Besides these
requirements, the over-all economic outlook and population pressure in
both Alaska and the mainland of the United States must be considered. One
needs to recall that large areas of soils suitable for agriculture still
exist in the States. In cognizance of these sets of considerations, Kellogg
and Nygard (3) estimate that under anything like present economic conditions
the total area of soils in Alaska suitable for crops is less than 1,000,000
acres, probably much less. This figure does not include the larger acreages
suitable for grazing; as summer grazing is plentiful, winter feeds will
EA-PS. Nygard and Orvedal: Soils of Alaska
limit animal production. After seeding well-kept gardens in which hardy,
cool-season vegetables grow luxuriantly under good husbandry, even far
north of the Arctic Circle, one is apt to become overenthusiastic about
farming possibilities. It must be remembered, however, that the choice of
vegetable crops which will grow out-of-doors, even with the use of cold
frames and hotbeds, is limited, and that the growing of more than hardy
vegetables is needed to make a living in an expanding agriculture.
Soil-Forming Factors
Soils in Alaska, as everywhere else in the world, are a product of
five genetic factors — climate, vegetation, parent material, relief, and
age. In the following paragraphs each of the five factors will be considered
in relation merely to Alaska.
Climate
varies considerably over the Territory. On most of the main–
land, however, it is prevailingly frigid in winter and mild to cool in
summer, with the average annual precipitation ranging from 5 to 12 inches.
On the plains adjoining Bering Sea and the Arctic Sea, the temperature is
lower in summer and higher in winter than in the interior, where extremes
of 100°F. and −78°F. have been recorded. Fogs and strong winds are common
on these plains but are uncommon in the interior. On the Aleutians and along
the southern coast, including southeastern Alaska, average annual temperature
and precipitation are much higher. Table 1 (5) shows some of the climatic
elements for stations selected to represent different parts of the Territory.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table 1. Selected Climatic Data for Four Stations in Alaska
.
|
|
Station
|
Average annual
precipitation,
inches
|
Average annual
temperature,
°F.
|
Months with
average
temperature
above 32°F.
|
|
Point Barrow
(northern arctic
Alaska)
|
4.23
|
10
|
3
|
|
Fairbanks
(interior subarctic
Alaska)
|
11.71
|
24
|
5
|
|
Anchorage
(southern Alaska)
|
14.56
|
35
|
7
|
|
Dutch Harbor
(eastern Aleutian
Islands)
|
58.61
|
40.4
|
11
|
Under the cold climate of most of mainland, especially the part
north of the Arctic Circle, the soil at the surface remains frozen from
one-half to three-fourths of the year; and below a depth ranging
[:
]
from
several inches to a few feet, the ground remains frozen all the time. This
permanently frozen ground prevents downward percolation of water released by
the surface soil when it thaws; and consequently, in northern Alaska in
particular, the surface soil is prevailingly wet when thawed even though
precipitation is low — indeed so low that, were this a temperate rather
than a frigid region, dry desert conditions would prevail.
Vegetation
in northern Alaska is of the tundra type — with low shrubs,
grasses, and sedges — commonly associated with arctic regions elsewhere.
But this type of vegetation extends southward along the western coast and
continues on across the Aleutian Islands, far from the true Arctic. Thin
EA-PS. Nygard and Orvedal: Soils of Alaska
forests, mainly coniferous ones, similar to the taiga forests of the
Soviet Union, prevail below approximately 2,300 feet in the Fairbanks
area of interior Alaska. Above this elevation the vegetation is of various
forms of tundra, trees being generally absent. Dense forests of large trees,
mainly coniferous ones, dominate southern Alaska from sea level to elevations
of some 2,000 feet, and in southeastern Alaska to higher latitudes near 3,000
feet. Throughout much of Alaska, some kind of rough fibrous organic mat
forms an insulating cover to the soils. More information on vegetation is
given in the discussion of the various great soil groups.
Parent material
in most of
[:
]
the nonmountainous parts of Alaska
consists wholly or partly of coarse silt and very fine sand that occur as
loesslike materials in the uplands and as alluvian on the flood plains.
Outside the flood plains, the coarse silt forms a blanket ranging in thick–
ness from as little as one inch to as much as a hundred feet or even more.
It is thinnest on the hills and ridges and thickest in the valleys. Where
it is thicker than approximately three feet, it alone forms the parent
material. Where it is thinner, it forms the parent material for the upper
part of the soil, and whatever is below — usually water-deposited sand
^
and
^
gravel or stony residuum from bedrock — forms the parent material for
the lower part.
In the mountainous parts of Alaska, silt is a negligible parent
material. Here disintegrated bedrock forms the principal parent material,
but even this is only a few inches thick on most mountain slopes.
Relief
indirectly modifies the effect of vegetation and climate, which
in their turn directly affect
g
^
t
^
soil formation. With it are associated
drainage and erosion. This relief, or lay-of-the-land, varies from the
EA-PS. Nygard and Orvedal: Soils of Alaska
precipitous slopes of Brooks Range, Alaska Range, and others to the nearly
lev
a
^
e
^
l plains, terraces, lowlands, and basins along the coasts and rivers.
Mountainous or near-mountainous areas, however, are more extensive than
plains. Innumerable ponds and small lakes are a distinctive feature of
nearly all Alaskan plains (Fig. 1). Microrelief, consisting of low mounds
separated by depressions, further characterizes the tundra plains (Fig. 2).
Age
of soils in Alaska varies, but most of them are “young” in the
sense that they have undergone but little horizon differentiation and lack
well-defined profiles. Soil formation has been slow on the high mountains
and in other extremely cold parts of Alaska, also in gravelly, cobbly, and
rubbly parent material in the warmer parts.
Great Soil Groups
Alaska, like any other vast region, has many different combinations of
the five soil-forming factors. As each significant combination of these gives
rise
[:
]
to its own type of soil with an individual set of characteristics,
many different kinds of soils have naturally developed.
A soil can be defined only as a combination of internal and external
characteristics. Internal characteristics of a soil are studied through
its profiles, and external characteristics through its related natural
landscape. Narrowly defined sets of characteristics are called “soil types.”
These may be grouped into broadly defined “great soil groups” (1). Examples
of soil types are described in this article, but they are discussed as
representatives of the great soil group to which they belong. The great
soil groups of Alaska (3) are listed as follows, the categories zonal,
intrazonal, and azonal being explained in references (1) and (3):
EA-PS. Nygard and Orvedal: Soils of Alaska
A. Zonal
1. Tundra
a. With permafrost
b. Without permafrost
2. Podsol
B. Intrazonal
1. Subarctic brown forest
2. Bog
3. Half-bog
4. Groundwater Podsol
5. Mountain tundra
6. Alpine meadow
C. Azonal
1. Alluvial
a. From general alluvium
b. From local alluvium
2. Lithosol
3. Regosol
Tundra Soils
. Tundra soils are characterized by a tough, fibrous,
organic mat on the surface which is underlain by a few inches of dark-colored,
humus-rich material that merges into light-colored, gray or mottled soil
beneath. This extends into permafrost or to the unaltered parent rock.
The organic (A
oo
and A
o
and A
1
) horizons are rather distinct from the lower
mineral (B and G) horizons. The B
.
H
^
h
^
orizon, on the other hand, generally
merges with the G (gleyed) horizon which in turn grades into the C or
slightly altered parent material. Wherever they have been examined in summer,
EA-PS. Nygard and Orvedal: Soils of Alaska
these soils have always been
s
^
w
^
et at some depth and, in most places, at
the surface. Largely because of the long periods of freezing and water–
logging, little leaching and eluviation have taken place, but some soil
material has been transported from one horizon to another or mixed by
pressures on the saturated, thawed horizons during freezing that occurs
in the late fall and early winter. Because of low temperatures, the
physical processes of weathering and soil formation dominate over the
chemical processes.
Even though tundra soils have always been wet when examined, they do
have a considerable range in drainage condit
^
i
^
on, and a succession of plant
associations from wetter to drier soils has been noted in enough places
to make a few preliminary generalizations. On the wettest soils several
different species of sedges, including tussocky cotton grasses (
Eriophorum
spp.),
grow well in mixtures of other grasslike plants, mosses, lichens, her
v
^
b
^
aceous
plants, dwarf woody plants, and creepers. On less
[:
]
wet soils, mixtures
of dwarf heathy shrubs, lichens, and mosses dominate over sedges; and
on the least wet soils, which also are generally shallow, are patches of
Dryas
, grasses (such as
Poa
and
Festuca
spp.), certain species of sedges
(
Carex
^
Carex
^
), and other herbaceous plants. Associated with the tundra soils
are innumerable ponds in which grow algae and other aquatic plants, with
scattered patches of floating or submerged plants, the most frequent of
which appear to be pondweeds (
Potamogeton
spp.), At the margin of these
ponds are water-tolerant sedges, and on slightly higher, less moist places
are horsetails (
Equisetum
spp.) and bluejoint (
Calamagrosti
a
^
s
^
canadensis
)
that grow with the sedges.
In addition to the plants already named, dwarf shrubs and prostrate
EA-PS. Nygard and Orvedal: Soils of Alaska
woody
[:
]
plants are numerous. Willows (
Salix
spp.) and alder (
Alnus crispa
)
grow on moist soils. Dwarf shrubs most commonly observed in the arctic
tundra are a birch (
Betula nana
) and two dwarfish heaths, narrow-leaved
Labrador tea (
Ledum palustre
) and a blueberry (
Vaccinium uliginosum
).
Two species of raspberry, arctic bramble (
Rubus arcticus
) and baked-apple
or cloudberry (
Rubus chamaemorus
), are also common.
Permafrost is not necessarily a characteristic of tundra soils,
although those with permafrost are many times more extensive than those
without. Its distribution in these soils is brought out in the two broad
subgroups: one with permafrost, representing the cold extreme, the other
without it, representing the warm extreme.
Tundra with Permafrost
. In Alaska, tundra with permafrost is found
in the cold, lake-dotted, treeless plains bordering the Arctic Sea and the
northern Bering Sea. The largest area occupies the arctic coastal plain.
Where these soils were examined at Point Barrow, they have a characteristic
microrelief with flattened, raised “polygons” separated by more heavily
vegetated shallow troughs about 2 feet lower than the high parts (Fig. 2).
The raised portion is partly bare and partly covered with lichens, prostrate
willows with branches some 3 or 4 inches long, sedges, and other plants.
Grasses growing in this area are
Poa arctica
,
P. alpina
,
P. pratensis
,
Festuca
sp.,
Agrostis
sp., and
Calamagrostis
.sp. The low parts between
the polygons have a dense sod of sedges with some mosses. Two profiles,
the first from the high part, the second from the low part, are described
in Table I.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table I. Profile Characteristics of Tundra with Permafrost
.
|
|
Horizon
|
Depth, inches
|
Description
|
|
|
High part
|
|
[:
]
00
|
1 to 0
|
Intermittent mat of roots and stems
|
|
A
11
|
0 to 3
|
Dark grayish-brown and dark reddish–
brown silty loam, rich in humus and
with many fine roots
|
|
A
12
|
3 to 11
|
Dark grayish-brown and dark reddish–
brown silty loam, rich in humus and
with few living roots; cold on
July 12, 1946
|
|
B to G
|
11 to 12
|
Upper part of solidly frozen layer of
very dark brown to black silty loam,
rich in humus, and mottled and streaked
with nearly white ice
|
|
|
Low part
|
|
A
00
|
1 to 0
|
Mat of roots and stems
|
|
A
1
and A
0
|
0 to 3
|
Dark reddish-brown silt filled with
roots to form a turf
|
|
B to G
|
3 to 9
|
Mottled grayish-brown and very dark
brown silty loam, rich in organic
matter; solidly frozen below 9 inches
July 12, 1946
|
Laboratory data on these soils indicate considerable variations in both
texture and organic matter. The high values for base-exchange capacity and
exchangeable hydrogen follow closely the organic matter content. Available
phosphorous is very low, at least judging by standards in the continental
United States (3).
Tundra without Permafrost
. Tundra soils without permafrost are found
in the uniformly cool climate of the Aleutian Island chain and the adjacent
EA-PS. Nygard and Orvedal: Soils of Alaska
western t
r
ip of the Alaska Peninsula, where they are associated with the
wetter bog and half-bog soils and the steeper, shallower and drier lithosols.
Near Cold Bay at the tip of the Alaska Peninsula, these soils occupy gently
undulating plains, alluvial fans, and foot slopes. They freeze each winter
to depths of 4 to 5 feet, but thaw out during the summer. The surface has
a regular microrclif with mounds 3 to 7 feet across and 6 inches to 2 feet
high. An example of this broad soil group was examined (see Table II) on
a gently undulating plain under a cover of crowberry, dwarf willows, sedges,
Dryas
, and various grasses and mosses (Fig. 3). It has developed from volcanic
ash reworked by water, the ash overl
a
ying water-laid gravel.
|
Table II. Profile Characteristics of Tundra without Permafrost
.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
00
|
3 to 2
|
Mat of living moss and roots
|
|
A
0
|
2 to 0
|
Dark reddish-brown peaty
^
^
mat
|
|
A
1
|
0 to 2
1/3
^
1/2
^
|
Dark reddish-brown, very fine sandy loam,
softly and finely granular
|
|
B
10
|
2 1/2 to 12
|
Dark reddish-brown, silty, very fine,
sandy loam; slightly compact, but
granular and friable; some roots
|
|
B
11
|
12 to 32
|
|
|
C
|
32 to 36
|
Reddish-brown and brown friable loam
that rubs to a slick smear
|
|
D
|
48
|
Gravel
|
Morphological and analytical data on this soil profile and others
[:
]
belonging to this broad group from the Aleutian Islands — Adak, Shemya,
EA-PS. Nygard and Orvedal: Soils of Alaska
Amchitka, Umnak, and Dutch Harbor — reported upon in detail by Kellogg
and Nygard (3) — indicate a characteristically low clay content in relation
to silt and very fine sand. The base-exchange capacity i
n
^
s
^
high because
of the high content of organic matter; exchangeable hydrogen and acidity
are also high. The base status and available phosphorous are low to
exceedingly low. Mineral plant nutrients — calcium, magnesium, manganese,
potassium, and phosphorus — are highest at the surface, indicating a
concentration due to plants. The carbon-nitrogen ratios are relatively
wide, as are those in peat soils.
Podsols
. These are often expected to be the normal soil of the boreal
forest, but actually well-developed podsols with prominent gene
g
^
t
^
ic horizons
are here comparatively scarce. The subarctic brown forest soils, instead
of podsols, dominate the well-drained positions. More frequently inter–
mingled with the subarctic brown forest soil
d
^
s
^
are weakly developed podsols
that are transitional between the well-developed podsols and the subarctic
brown forest soils.
The farthest north that podsol soils have been observed in Alaska are
two small spots in the Yukon-Tanana upland, one being about 35 miles north
of Fairbanks and the other just east of Circle Hot Springs. The podsol
north of Fairbanks occupies a gently rolling upland covered with a second–
growth white birch, aspen, and a few spruce, with an undergrowth of
blueberry, Labrador tea, and a few alders. The podsol east of Circle
Hot Springs lies on an undulating plain covered with a thick stand of
young aspen, from 3 to 8 feet high, along with a few young white spruce
and a ground cover of crowberry, mountain cranberry, and lichens. A
description of the podsol observed near Circle Hot Springs is given in Table III.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table III. Profile Characteristics of a Podsol.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
00
|
2 to 1
|
Nearly fresh leaves and twigs
|
|
A
0
|
1 to 0
|
Dark reddish-brown fibrous root and
leaf mat containing mycorrhzo
^
ya
^
l
mycelium and charcoal; pH 4.8
|
|
A
1
|
|
Exceedingly thin, very dark-brown
humus soil; nearly
about
absent in
some places
|
|
A
2
|
0 to 2
|
Light gray, ashy, fine sandy loam
containing many roots; weakly developed
platy structure; slightly vesicular;
ranges from less than 1/2 to 3 inches
thick; pH 4.3
|
|
B
1
|
2 to 5
|
Light yellowish-brown, silt loam, with
many roots; weakly developed mixed
subangular blocky and platy structure;
easily friable; a few pebbles; pH 5.0
|
|
B
2
|
5 to 11
|
Reddish-brown, brown, and yellowish–
brown loam, with few roots; weakly
developed fine subangular blocky structure;
easily friable; many pebbles, mainly of
gneiss and quartzite; soil is slightly
cemented; horizon boundaries and thick–
ness are irregular; pH 4.8
|
|
C
|
11 to 18
|
Light yellowish-brown, gravelly sandy
loam; loose and porous; ph 5.4
|
Like other podsols of the Far North, this soil is hallow, the thickness
of the solum ranging from 6 to 20 inches. Morphological and analytical data
suggest moderate podsolization. Ferric oxide appears to have moved into
the B
.
hori
zon. The organic carbon and nitrogen decrease with depth, and
the organic mat is raw in the surface A horizon and fairly well decomposed
in the B, with carbon-nitrogen ratios of 32 and 14, respectively.
EA-PS. Nygard and Orvedal: Soils of Alaska
Podsols having the best-developed profiles in Alaska were found in
the upper Susitna Valley of the Cook Inlet lowlands. Several types with
prominent genetic horizons lie on high sandy and gravelly terraces and
eskers. One of the profiles is shown in Figure 4. In several types the
B horizon is enriche
s
^
d
^
with both humus and iron oxide, and its base-exhange
capacity is several times that of the A
2
horizon. These soils are extremely
acid, and very low in base saturation. Moderately developed podsols are
common in the Anchorage and Knik areas, where they have developed mainly
from fine sandy outwash materials.
Subarctic Brown Forest Soils
. These are characterized by a tough,
fibrous, organic mat at the surface which is underlain by several inches
of a brown surface mine
d
^
r
^
al horizon that merges through gradual transition
of brown, reddish-brown, and yellowish-brown, mottled with pale brown and
light gray, to the parent material which extends down to the unaltered parent
rock or
[:
]
permafrost. Even where they are not underlain by permafrost,
the lower horizons are cold and contain few or no roots. The soils are
unleached, except in the surface, and are low in clay content in relations
to silt and sand. Like podsols, they have acid organic layers (A
00
and A
0
)
on the surface, but lack the ashy gray A
2
horizon which is characteristic
of the podsols.
Subarctic brown forest soil
d
^
s
^
appear to occupy a stage of immaturity
before the development of podsols. Whether they will in time become podsols
is not know
^
n
^
, as they seem to be reasonably stable under the boreal forest
of Alaska. They are of greater agricultural importance than other rather
widespread soils, because many of them, though by no means all, are potentially
suitable for farming (Fig. 5). A serious problem in their use, however, is
EA-PS. Nygard and Orvedal: Soils of Alaska
caused by permafrost. Under cultivation, this tends to disappear, causing
caves, gullies, and other rough surfaces due to melting of ice blocks in
the
[:
]
substratum (Fig. 6).
Subarctic brown forest soils have developed in the subarctic where
the climate is colder than in the parts of North America where pod
o
sols
are widespread. There is, however, considerable overlapping of climatic
limits, and hence in some parts of Alaska both pod
o
sols and subarctic Brown
forest soils have developed under the same climate. Subarctic brown forest
soils occur
[:
]
outh and east of the region of tundra soils, merging with the
tundra in places. Excellent examples can be seen north of Fairbanks, on
well-drained valley slopes, terraces, and low ridges. A representative
type is located on the Agricultural Experiment Station near Fairbanks, on
a gentle south-facing slope. Part of this soil type is cultivated and part
is under a plant cover of white spruce, white birch, and aspen trees, 25 to
50 feet high, with an undergrowth of tall blueberry, wild rose, horsetail,
mountain cranberry, and a few mosses. A description of a subarctic brown
forest soil is given in Table IV.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table IV. Profile Characteristics of Subarctic Brown Forest Soil.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
0
|
2 to 0
|
Dark reddish-brown, fibrous organic mat of
leaves, needles, twigs, mosses, and roots;
lower portion is partly disintegrated;
pH 6.6
|
|
A
11
|
0 to 3
|
Brown, very fine sandy loam, rich in organic
matter; weakly developed crumb structures;
very friable; many living roots and a few
worm casts and mycorrhizal mycelia; pH 6.0
|
|
A
3
|
3 to 5
|
Yellowish-brown, very find sandy loam,
slightly specked with light grayish-brown;
very weakly developed fine platy structure;
very friable; slightly vesicular; many
living roots; pH 6.0
|
|
B
11
|
5 to 10
|
Yellowish-brown, very fine sandy loam, specked
with yellowish-red; weakly developed fine
platy structure; micaceous; compact in
place, but easily friable when removed;
many living roots; pH 6.1
|
|
B
12
|
10 to 18
|
Light yellowish-brown and light olive-brown,
very fine sandy loam, slightly mottled with
olive; weakly developed fine platy structure;
compact in place, but friable when removed;
few roots; highly micaceous; pH 6.4
|
|
C
1
|
18 to 28
|
Pale-yellow, very fine sandy loam, mottled with
yellowish-red and yellowish-brown; friable;
highly micaceous; slightly laminated with few
small dark spots between laminations; pH 6.1
|
|
C
2
|
28 to 45
|
Light brownish-gray, very fine sandy loam;
highly micaceous; laminated; pH 6.5
|
Representative types in this broad soil group have been found in many
other parts of the Territory, particularly in areas where agricultural use
is made of the land. Such sites are on gravelly terraces at Big Delta, on
terraces and sandy old alluvium near Circle and Circle Hot Springs, on glacial
EA-PS. Nygard and Orvedal: Soils of Alaska
moraines, in old lake-settling basins, and on old alluvium between Chitina
and McCarthy, on Sourdough Ridge and high river terraces near McCarty, and
in the Upper Matanuska Valley near Palmer.
Bog Soils
. Bog soils, locally termed “muskeg,” consist chiefly of
organic matter in a more or less decomposed state. The relatively raw
material is called peat, and the more thoroughly decomposed material, muck,
though it should be noted that in some parts of Alaska, especially at
Fairbanks, the term “muck” has long been used by miners for beds of silty
organic matter and for the silty organic residues in placer mining.
Bog soils are found in all parts of Alaska in lowlands, in seepage
areas, and even on moderate slopes with underlying permafrost or hard rocks.
The succession of plants from ponds to quaking mat, and thenc
d
^
e
^
to relatively
dry land where trees have encroached, was observed in may parts of the
Territory. The moist, cool Pacific coastal climate is especially favorable
to the formation of these soils. Here they are found on rather strong slopes.
Deep peat bogs appear to be less widespread in the coldest arctic region and
on very high mountains. Dachnowski-Stokes has studied some of these soils,
particularly from a botanical viewpoint (2).
Alaska has many types of bog soils similar to those in the northern
Lake States. In addition there are comparable soils in other parts of the
world. For example, the bog soils in the tidal basins are similar to those
developed in salt-water marshes along the Pacific coast. These soils are
neutral to alkaline in reaction, being high in bases. At the other extreme
are the soils of “raised” bogs or “high moors,” which resemble those that
are so common in
N
northern Europe, having a cover of
Sphagnum
moss peat
and
Sphagnum
mosses built up to a height of several feet near the center.
EA-PS. Nygard and Orvedal: Soils of Alaska
They are strongly to extremely acid, and very low in mineral plant nutri
a
^
e
^
nts.
On these bog soils the growing mosses get few nutrients apart from those
carried in the rain water and those available in the underlying peat.
One of the more common types of bog soil
s
in the Anchorage area is,
like the Greenwood peat of the northern Lake States, one of the rawest of
the bog soils in its vicinity. Because of its rawness, extreme acidity,
and low content of lime and other plant nutrients, it is not recommended
for agricultural use. A description is given in Table V.
|
Table V. Characteristics of Bog Soil.
|
|
Depth, inches
|
Description Z
|
|
0 to 12
|
Mixed living and dead
Sphagnum
and many roots
and rootstocks from woody plants and sedges
|
|
12 to 40
|
Reddish-brown and yellowish-brown, fibrous,
sedge peat, very slightly decomposed;
spongy; matted; frozen in the lower part
|
|
40 +
|
Dark-brown moss peat grading into sedimentary
peat
|
Half-Bog
. Half-bog soils, in comparison with bog soils, have thin peaty
and mucky horizons; but even in half-bogs these may be as much as a foot in
thickness. They overlie gray mineral soil (gley) that is wet during all or
a large part of the time (Fig. 7). Half-bog soils, like bog soils, occur
in poorly drained places.
Half-bog soils are found in all climatic regions of Alaska and are among
the most widespread soils in the interior. Here they occur under plant covers
of sparse to medium stands of scrubby white or black spruce and an undergrowth
of dwarf birch and dwarf heathy shrubs. Willows and alder are dominant on some
EA-PS. Nygard and Orvedal: Soils of Alaska
types, and larch (tamarack) on others. The ground cover consists, for the
most part, of peat-forming mosses, especially
Sphagnum
spp., along with
lichens, several very dwarf heathy shrubs, creepers, and horsetails. Some
are under open stands of sedges, grasses, and dwarf shrubs.
In the Fairbanks area several types of half-bog soils occur on alluvial
bottom lands and low terraces in the lower Tanana Valley and in the Chena
Slough, a channel of the Tanana River. Subarctic brown forest soils occupy
the better-drained terraces and valley slopes, and bog soils the wetter,
ponded areas. A common type of half-bog soil is described in Table VI.
|
Table VI. Profile Characteristics of a Half-Bog Soil.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
0
|
5 to 0
|
Brown moss peat, impregnated with roots of
woody plants and silt particles; also a
few bits of charcoal
|
|
G
1
|
0 to 5
|
Gray and grayish-brown, very fine sandy
loam, mottled with pale-yellow and
reddish-brown; compact in place, but very
friable when removed; weakly developed
platy structure
|
|
C
1
|
5 to 13
|
Gray and light-gray, silty very fine sand;
very friable
|
|
C
2
|
13 to 24 +
|
Light-gray and very pale-yellow, silty very
fine sand; laminated; micaceous
|
|
|
35
|
Frozen layer on July 1, 1946
|
The profile described in Table VI was under a native cover of a moderately
thick stand of spruce, 3 to 20 feet high, along with a few aspen and willows,
and an undergrowth of blueberry, Labrador tea, crowberry, mountain cranberry,
and many mosses and lichens.
Sphagnum
mosses dominated the ground cover, but
EA-PS. Nygard and Orvedal: Soils of Alaska
Polytrichum
and occasional
Hypnum
species were also present. This profile,
like others examined, shows that vegetation has had a great influence on the
surface horizons but not on the lower ones.
Many other types of half-bog soils were found in other parts of the
central valley and plateau through which the Yukon, Tanana, Kuskokwim, and
other rivers flow, and furthermore in the Copper Center basin, where they
also predominate, and in the Cook Inlet lowlands.
Groundwater Podsol
. Groundwater podsols are developed under the
influence of a high and fluctuating water table which produce
d
^
s
^
alternate
wet and dry conditions in summer. They resemble “humus” podsols in which
the B horizon is enriched with both humus and iron oxide.
Many different types of these soils occur in the Cook Inlet lowlands,
where they are associated with podsols and bog soils. In the Talkeetna
Mountains, variations within this soil group are found as high as the timber
line (about 3,000 feet) or higher.
A good example of a groundwater p
e
^
o
^
dsol can be observed east of Willow
Station on the Alaska Railroad (see Table VII). The plant cover here is like
that of many bog and half-bog soils, consisting as it does of scrubby black
spruce with a thick undergrowth of blueberry, crowberry, mountain cranberry,
many species of mosses, dwarf dogwood, and a dwarf
Rubus
.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table VII. Profile Characteristics of Groundwater Podsol Soil.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
00
|
9 to 5
|
Light brownish-gray peaty mat of living
and dead
Sphagnum
mosses, roots, and
rhizomes; pH 3.5
|
|
A
0
|
5 to 0
|
Yellowish-brown, raw, spongy
Sphagnum
peat;
pH 4.0
|
|
A
1
|
0 to 1/2
|
Dark-brown mucky silt; weakly developed fine
granular structure; pH 4.0
|
|
A
21
|
1/2 to 2
|
Light grayish-brown loamy, very fine sand;
weakly developed fine platy structure; very
friable; very irregular in thickness;
pH 4.0
|
|
A
22
|
2 to 2 1/2
|
Light-gray loamy, very fine sand; very
friable; pH 4.0
|
|
B
21
|
2 1/2 to 5
|
Dark reddish-brown, fine sandy loam; weakly
developed fine granular structure; granules
are soft when moist; roots abundant; soil
has accumulated humus; pH 4.5
|
|
B
22
|
5 to 7
|
Reddish-brown, fine sandy loam; weakly
developed fine granular structure; granules
are harsh when dry; very weakly cemented
|
|
B
31
|
7 to 12
|
Yellowish-red, medium-to-fine sand; weakly
developed platy structure; pH 6.0
|
|
B
32
|
12 to 18
|
Strong brown, medium-to-fine sand
|
|
CG
|
18 to 28
|
Light olive-gray, loamy fine sand; pH 5.5
|
Mountain Tundra
. Mountain tundra soils and their native plant cover are
similar to the tundra soils previously described. The plant species inhabiting
these soils are not only stunted and prostrate but matted. Many dwarf shrubs
(predominantly heaths), mosses, lichens, and sedges, are the most common,
forming acid organic layers.
EA-PS. Nygard and Orvedal: Soils of Alaska
These soils occupy high parts of mountains, above the timber line,
in inaccessible areas where they are not likely to be much observed. They
may be seen in several places on the Tanana-Yukon upland between Fairbanks
and Circle, in Mount McKinley National Park, and in the Talkeetna Mountains.
Several types grade into half-bog soils, as does the mountain-tundra soil
described in Table
^
V
^
III; it was observed on Twelve
[] M
^m^ile Summit on the Tanana–
Yukon upland:
|
Table VIII. Profile Characteristics of Mountain Tundra.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
00
and A
0
|
3 1/2 to 0
|
Dark reddish-brown, fibrous moss peat and
living
Sphagum
; pH 4.3
|
|
A
1
|
0 to 5
|
Reddish-brown moss peat, moderately well
disintegrated and containing many tough
woody roots; pH 4.5
|
|
BG
|
5 to 10
|
Olive loam, slightly mottled with light
yellowish-brown; contains grit
;
^
,
^
pebbles
;
^
,
^
flakes of mica, and many roots; somewhat
sticky when wet and dries to weak irregu–
lar blocks and flakes; pH 4.9
|
|
C
1
|
10 to 12
|
Brown loam, containing many fragments of
micaceous schist; pH 4.9
|
|
|
12 +
|
Similar to horizon C, but frozen in July, 1946
and containing a greater proportion of schist
|
This soil occupies the top of a high ridge of micaceous schist. The
plant cover consists of a thick mat of
Sphagnum
mosses and many lichens along
with dwarf birch, dwarf and prostrate willows, blueberry, crowberry,
a
^
a
^
Ledum
,
mountain cranberry, and a few cotton grasses. Caribou graze on this vegetation
in summer.
EA-PS. Nygard and Orvedal: Soils of Alaska
Alpine-Meadow Soils
. These superficially look like a wet prairie soil
in that the soil horizons are poorly defined and the surface A horizon is
high in well-decomposed organic matter that very gradually diminishes with
depth. These soils generally are covered with a thin organic mat (less than
2 inches) beneath which is a humus-rich surface mineral horizon that is dark
brown or some shade of brown fading downward to dark grayish-brown, brown,
and grayish-brown, and generally streaked with high contrasting colors in
the lower part of the solum.
Alpine-
k
^
m
^
eadow soils occur above the timber line at greater altitudes and
on steeper and drier slopes than the mountain tundra and half-bog soils.
Lithosols are common associates. The native cover of alpine-meadow soils
consists, for the most part, of herbaceous plants of which
Dryas
, certain
sedges, lichens, grasses, and many flowering plants are characteristic. The
mosses present are, in general, not the peat-forming type of
Sphagnum
found
on mountain tundra and half bog soils. Alpine-meadow soils were observed
^
in the Talkeetna Mountains and in Mount McKinley National Park.
^
i
^
I
^
n the Talkeetnas, mound microrelief was also observed (Fig. 8). An alpine–
meadow soil on a high mountain east of Camp E
u
^
i
^
elson in Mount McKinley National
Park is described in Table IX.
EA-PS. Nygard and Orvedal: Soils of Alaska
|
Table IX. Profile Characteristics of an Alpine-Meadow Soil.
|
|
Horizon
|
Depth, inches
|
Description
|
|
A
o
|
2 to 0
|
Dark reddish-brown, fibrous organic and
root mat; pH 6.0
|
|
A
1
|
0 to 4
|
Dark reddish-brown and dark grayish-brown
loam, weakly developed fine granular structure;
many fine roots; pH 5.6
|
|
B
1
|
4 to 10
|
Dark yellowish-brown loam; weakly developed
granular structure, the granules are soft and
mellow; very friable; several fine roots;
pH 5.6
|
|
B
2
|
10 to 24
|
Dark yellowish-brown loam, streaked with
black and pale yellow; irregular granular
structure; easily friable; few roots; pH 5.4
|
|
C
|
24
|
Gray
si
^
is
^
h-brown, dark-gray, and light yellowish–
brown, gravelly, sandy loam; many quartzite
and few rhyolite pebbles; easily dug; pH 5.8
|
In this soil it is noted that the content of organic matter is high at
the surface but diminishes with depth. In comparison with tundra soils, the
organic matter is more highly decomposed, the alkaline status is higher, and
the acidity lower.
Alluvial Soils.
These are
d[:
]
derived from such freshly deposited
alluvium that few, if any, effects of vegetation and climate can be seen in
the soil profile. Many of these soils continue to receive additional sedi–
ments during flood periods.
Alluvial soils occur in many placed throughout Alaska. They occupy
flood plains, where they are formed from general alluvium. They also occupy
variously shaped areas in deltas, coves, and along lower valley slopes, where
they are formed largely from local alluvium. Although in the aggregate
EA-PS. Nygard and Orvedal: Soils of Alaska
these soils do not make up a large area, they are agriculturally important.
Those that are fairly well drained, not subject to frequent flooding, and
not too stony, are generally well suited for gardens and pastures, provided
the local climate is not too severe. Favorable local climates occur in
spots that benefit from the maximum amount of sunshine and warm air, and
are found on the lower parts of south-facing slopes.
Lithosols and Regosols
. Lithosols consist mainly of hard rock with
or without thin, irregular coverings of rubbly soils material. Alaska has
many large and small areas of these thin, rocky soils. They occupy much
of the high mountain terrain, many of the steep slopes of hills, and some
of the gentle slopes of mountains and hills that are excessively rubbly.
Regosols are soft or unconsolidated materials, with or without a thin,
irregular covering of soil material. Like lithosols they have scarcely any
pedogenic soil; but they are not stony, and roots can easily find a foothold.
Regosols occupy small areas throughout Alaska. They include relatively
fresh morainic debris left by retreating glaciers, beach sands, fresh wind-laid
deposits, volcanic ash, and cinders.
Distribution of Soils
The following paragraphs describe Figure 9, which shows the distribution
of associations of great soil groups in Alaska, and important permafrost
boundaries. The permafrost lines and parts of the boundaries of soil
associations are based upon published and unpublished data furnished by
the U.S. Geological Survey.
Map Unit 1
shows the principal areas of tundra soils. These soils occupy
the low coastal plains along the Arctic Sea and Bering Sea, where innumerable
ponds and lakes (Fig. 1
^
)
^
are associated with them.
EA-PS. Nygard and Orvedal: Soils of Alaska
Elsewhere, north and south of Brooks Range and northwest and northeast of
Alaska Range, the tundra soils lie at higher elevations — on top of hills
and low mountains — and have associated with them, for the most part,
lithosols. Other associates are alluvial, bog, half-bog, regosol, and
subarctic brown forest soils. Except for alluvial soils, which are present
in small percentages in all areas, these associated great soil groups occur
with tundra soils south of Brooks Range.
North of Brooks Range, permafrost is everywhere present near the surface
of the tundra soils. Elsewhere it is absent locally, and on the south side
of Bristol Bay may be absent altogether.
Areas of Map Unit 1
^
are
^
generally unsuitable for agriculture, at least for
the kinds practice
s
^
d
^
in temperate regions. The soils provide grazing for
reindeer and caribou, and can best be utilized for the production of these
hardy animals, as well as musk oxen and possibly yak.
Map Unit 2
includes mainly half
^
-
^
bog and subarctic brown forest soils,
but minor associates are alluvial, bog, and podsol soils. The soil association
occupies low, flat, lake-dotted alluvial plains and terraces in which are
intermingled a few hills. The half-bog, bog, and alluvial soils lie in
the
f
lowest, wettest places, in the alluvial bottom lands in particular,
whereas subarctic brown forest soils and the few podsols occupy the higher,
better-drained uplands.
Permafrost is generally present, although it is locally absent in many
places, especially along rivers. In the vicinity of Cook Inlet, however,
it is absent over most areas.
The subarctic brown forest soils in general, and some alluvial and
half-bog soils, are suitable for agriculture. They may be utilized to the
EA-PS. Nygard and Orvedal: Soils of Alaska
best advantage for hardy, short-season crops, and for meadows and pastures.
Following clearing, the surface of some of them may subside i
d
^
r
^
regularly
owing to melting of ice blocks in the substratum — thereby producing a
surface so uneven that the soils become difficult or impossible to cultivate.
Map Unit 3
consists mainly of subarctic brown forest soils on foothills,
and piedmont and river terraces, the terraces usually having a silty surface
and a gravelly substratum. Associated with these soils are half-bog and
bog soils in depressions and valleys, alluvial soils along streams, podsols
on terraces, and mountain tundra on included high hills and low mountains.
Permafrost is generally present, except around Cook Inlet lowlands;
but it is either absent or at least several feet beneath the surface in
many places, especially on south-facing slopes.
Most of the agriculture in Alaska, including that in Matanuska Valley
and the vicinity of Fairbanks, is on the subarctic brown forest soils of
this association. Several of the podsol, alluvial, and half-bog soils
are also arable. Hardy vegetables, including potatoes, quick-maturing small
grains, and grasses can be grown.
Map Unit 4
, which includes the large mountainous areas, consists
mainly of lithosols with considerable tundra and many minor
[:
]
oil associates.
Among these are alpine meadow, bog, half-bog, alluvial, regosol, podsol,
groundwater podsol, and subarctic brown forest soils. Most of the minor
associates are absent in the Brooks Range but occupy many small areas in
the southern mountains. In the Alaska and Coast ranges, glaciers and
permanent snow fields are conspicuous inclusions.
Permafrost is present nearly everywhere in the northern areas and in
many places in the southern areas, although it is absent on the Aleutians,
EA-PS. Nygard and Orvedal: Soils of Alaska
on Kodiak and adjacent islands, and on the mainland off the Pacific Ocean.
The areas are considered unsuitable for agriculture, but summer
grazing is feasible in parts of the southern mountains. Small areas,
some only large enough for a tiny garden, are capable of producing food
for people engaged in activities other than farming.
Ma
y
^
p
^
Unit 5
, which occupie
d
^
s
^
a narrow strip along the irregular coast
of southeastern Alaska, consists mainly of regosol, bog, alluvial soils,
and lithosols, with small areas of half-bog and podsol soils. Apart from
lithosols, the soils lie on low valley slopes, alluvial bottom lands,
deltas, and narrow coastal beaches. Permafrost is absent. Small scattered
areas are suitable for vegetable gardening, a few small fruits, and some
dairying.
EA-PS. Nygard and Orvedal: Soils of Alaska
BIBLIOGRAPHY
1. Baldwin, Mark, Kellogg, C.E. a
[:
]
^
n
^
d Thorp, James. “Soil classification,”
U. S. Dept. of Agriculture.
Soils & Men. Yearbook of
Agriculture
. Wash., G.P.O., 1938, pp.979-1001.
2. Dachnowski-Stokes, A.P.
Peat Resources in Alaska
^
Peat Resources in Alaska
^
. Wash, Dept. of
Agriculture, 1941. The Dept.
Tech.Bull.
no.769.
3. Kellogg, C.E., and Nygard, I.J.
Exploratory Study of the Principal
Soil Groups of Alaska
. U.S. Dept.Agric.
Monograph
no.7.
(In press)
4. U.S. Dept. of Agriculture.
Report on Exploratory Investigations of
Agricultural Problems of Alaska
. Wash., G.P.O., 1949.
The Dept.
Misc.Publ
. no.700.
5. U.S. Weather Bureau.
Climatic Atlas for Alaska
. Wash., G.P.O., 1943.
U.S. Army Air Forces. Weather Information Branch.
Report
no.444.
Iver J. Nygard and A.
[:
D
]
. Orvedal
Soils of Arctic Canada
EA-Plant Sciences
(A. Leahey)
SOILS OF ARCTIC CANADA
CONTENTS
|
|
Page
|
|
Nature of Soils
|
2
|
|
Mineral Zonal Soils
|
2
|
|
Mineral Azonal Soils
|
5
|
|
Organic Soils
|
6
|
|
Unfrozen Soils
|
6
|
|
Factors Affecting Soils
|
8
|
|
Climate
|
8
|
|
Vegetation
|
9
|
|
Parent Material
|
9
|
|
Topography
|
9
|
|
Age
|
10
|
|
Permafrost
|
11
|
|
Zones and Subzones
|
12
|
|
Major Zones
|
12
|
|
Subzones
|
13
|
|
Canadian or Pre-Cambrian Shield
|
13
|
|
Paleozoic Limestone Areas
|
13
|
|
Cretaceous Areas
|
14
|
|
Cor
c
^
d
^
illeran Region
|
14
|
|
Recent Alluvial Soils
|
14
|
|
Bibliography
|
16
|
EA-Plant Sciences
(A. Leahey)
SOILS OF ARCTIC CANADA
The soil region of the Canadian Arctic is considered by the writer
to be that part of northern Canada where permafrost occurs sufficiently
near the surface to affect soil development. As the southern boundary
of the region lies in the northern forests in country that is relatively
unexplored from a pedological viewpoint, the limits of the region are
not accurately known. However, the tentative southern boundary of the
permafrost area shown by Jenness (2), and reproduced on the map (Fig. 1),
is probably the best approximation to date of the southern limits of the
Arctic. The term “arctic region” as used in this article refers to this
region considered from a pedological standpoint.
Information on the nature, genesis, and pedogenic and geographic
relationships of the soils occurring in the Canadian Arctic is scanty.
Feustel, Dutilly, and Anderson (1) have reported on the nature of a number
of soil samples collected by Dutilly in the tundra region of northeastern
Canada. Leahey (3; 4) has described the morphology of some arctic types
in northwestern Canada, and given some chemical data for them. Valuable
information on soils may also be obtained from geological, botanical, and
other reports dealing with the arctic region. Although such reports do not
specifically describe the soils, they often give pertinent information on
Fig. I.
EA-PS. Leahy; Soils of Arctic Canada
the landscape, vegetational cover, and geological nature of the surface
deposits.
While an authoritative account of the soils of the arctic region of
Canada cannot be written until more pedological studies have been conducted
there, the writer believes that on the basis of existing information it
is possible to speculate, with a reasonable degree of confidence, on the
kinds of soil that are found or may be expected in this vast region of
North America.
Nature of the Soils
Both mineral and organic soils are widely distributed in the arctic
region. As, in parts of the region, most of the soils have an organic
surface layer of varying thickness, the division of the soils into these
two categories must necessarily be a somewhat arbitrary one. Pedologists
in Canada usually place soils having less than one foot of organic matter
over the underlying mineral material in the mineral group, and those with
a foot or more of surface organic layer in the organic group. This rule
of thumb could be applied to the arctic soils, although the writer modified
it to the extent that he also placed in the organic group soils where
permafrost was encountered in the organic layer above the depth of one foot.
Mineral Zonal Soils
. From their examination of 37 soil samples
collected from the arctic region surrounding Hudson Bay, Feustel, Dutilly,
and Anderson (1) concluded that “No evidence of well defined profile
characteristics was observed in the areas examined. The character of the
parent rock, whether rugged and hard or comparatively soft and readily
powdered apparently plays an important role in determining the extent of
EA-PS. Leahey; Soils of Arctic Canada
profile development.” While the last statement would imply that there
was more noticeable profile development on the finer-textured deposits,
these authors stress the fact that there was no appreciable profile
development in any of the soils examined.
The writer’s observations on the soils of the North were made along
the Mackenzie and Yukon rivers where climatic and vegetative factors were
more favorable for soil development than in the areas that were examined
by Dutilly. Yet even under these more favorable environmental conditions
for soil development, the soil profiles were quite immature. The profile
described by Leahey (3) as being representative of the subarctic zones
indicates the extent of profile development under a mixed forest and for
that reason his description is repeated below.
“The zonal soil selected as being representative of the Sub-Arctic
zone was taken on a level plain under a mixed forest of spruce, birch,
alder and willow near the settlement of Fort Norman. Under a cover of
about 2 inches of live moss, this soil had the following profile charac–
teristics.
|
2-0
|
inches
|
Semi decomposed moss and leaves
|
pH 5.2
|
|
0-4
|
inches
|
Grey brown fin
d
^
e
^
sandy clay loam
|
pH 6.5
|
|
4-10
|
inches
|
Light grey brown fin
d
^
e
^
sandy clay loam
|
pH 7.8
|
|
10-18
|
inches
|
Pale olive fin
d
^
e
^
sandy clay loam with
some yellow brown mottling
|
pH 8.3
|
|
18-30
|
inches
|
Pale olive fin
d
^
e
^
sandy clay loam with
yellow brown mottling
|
pH 8.3
|
|
30-39
|
inches
|
Same as 18-30” depth
|
pH 8.4
|
All horizons had weakly developed granular structure. On August 20, 1945
permafrost was encountered at 39 inches.
EA-PS. Leahey; Soils of Arctic Canada
The above description shows that below 10 inches in the min
d
eral
soil, no horizon differentiation had taken place. The chemical data for
this profile supported the field observations that this soil was in a
youthful stage of development. The soil showed as much profile develop–
ment as any observed by the writer on the forested permafrost uplands
along the Mackenzie River. However, he has seen soils under similar
conditions in the Yukon which had somewhat more development as indicated
by a greater thickness of the upper weathered horizon of mineral soil,
although there was little difference in the type of profile development.
In fact, all the zonal soils examined in the forested areas of the arctic
region had the same kind of profile development, namely, an organic surface
layer; a fairly abrupt division between the organic layer and the mineral
soil; and a brown upper mineral horizon which graded quickly into the
mineral parent material that was more or less mottled.
Calcium carbonate, when present in the parent material, was usually
found immediately under the brown weathered horizon but sometimes occurred
in that horizon. Beyond the slight leaching downward of the calcium
carbonate, no evidence of elluviation and illuviation was seen in these
soils. Differences between them could be attributed mainly to differences
in parent material, but topographic position also played a part in that it
affected the depth of the surface organic layer. Soils on level land and
on the lower positions on slopes usually had a thicker organic layer than
the soils occurring on better-drained sites.
The writer had had the opportunity of examining the soils of the
treeless tundra only in a small area on the west side of the Mackenzie
River about 30 miles below Aklavik, where the parent material was a clay
EA-PS. Leahey; Soils of Arctic Canada
till. The general type of the profiles examined did not differ materially
from those previously described. In fact, these tundra soils were almost
identical with soils observed on similar parent material but under a
forest cover between Fort Good Hope and Arctic Red River. Not only were
the profiles similar but both had the same kind of polygonal structure
commonly found in clay soils in the arctic region.
It is evident from the foregoing discussion that the soils of the
northern parts of Canada affected by permafrost are in an immature stage
of development in both the forested and nonforested areas. While, in
general, those of the forested area show more development, it is doubtful
if the zonal soils of the two areas can be classified into different large
soil groups. On the soils with permanently frozen subsoils, the presence
or absence of tre
s
^
e
^
s does not appear to have significantl
affected signifi–
cantly the type or extent of profile development. It would also seem that
the process of podsolization is relatively inactive in soils where perma–
frost occurs sufficiently near the surface to affect soil development.
Mineral Azonal Soils
. Recent alluvial soils are found along the
rivers and streams in the North. These soils do not show any development
in profile characteristics except for an accumulation of organic matter
in the upper part of the soil. Except where annual flooding occurs, per–
mafrost is found in these soils at about the same depths as on the zonal
soils of the adjacent uplands.
Another important group of azonal soils, as far as areal extent is
concerned, is the lithosols. These soils are either too coarse in texture
to permit any soil development, or they occur on mountain slopes where
erosion keeps pace with any soil development which could take place.
EA-PS. Leahey; Soils of Arctic Canada
Organic Soils.
Little study has been made of the organic soils in
the arctic region of Canada. Feustel, Dutilly, and Anderson (1) have
given partial analyses for fourteen samples of organic materials. These
analyses showed that, taken as a whole, no striking differences were
noted in the arctic samples as compared with samples from temperate regions.
In connection with these samples, it is of interest to note that only
their
three were considered to be peats, the others being more of the nature of
mucks or peaty mucks as indicated by their physical character and by the
magnitude of the ash content.
In the forested area of the arctic region in northwestern Canada, the
organic soils do not appear to differ appreciably in their nature from
those found farther south where permafrost is absent. Most of the organic
deposits appear to be derived from mosses, often with an admixture of woody
peat, but sedge peats are not uncommon. The presence of a frozen layer
in these soils at shallow depth, usually 9 to 12 inches from the surface,
discourages attempts to examine the organic deposits below this depth.
The surface layer of most of these organic deposits is raw peat, often
turning into peaty muck or mucky peat at, or near, the top of the frozen
layer. Sphagnum moss appears to be the major contributor to the formation
of these organic soils.
While raw peat is the dominant organic soil in the forested area,
the typical organic soil on the tundra near Aklavik appears to be a peaty
muck. The deposits examined by the writer were dark brown to black peaty
mucks covered with about two inches of living moss.
Unfrozen Soils.
There are some soils in far northwestern Canada which
are not affected bypermafrost. Such soils fall into three general groups;
EA-PS. Leahey; Soils of Arctic Canada
some of the coarse-textured lithosols, fine-textured alluvial deposits
which are subject to annual flooding, and soils occupying particular
topographic positions. The first two groups are azonal soils, i.e.,
they lack any profile development, while the last-mentioned group has
a distinctive type of profile.
Fine-textured alluvial soils lacking permafrost to a depth of at
least 9 feet occur along the Mackenzie River and are quite extensive on
the delta of that river. Such soils almost invariably have a high water
table, usually at about 3 feet. The area of these soils is clearly
marked by a different vegetation from that of the alluvial soils with
permafrost, spruce being entirely absent on the former. The break between
the spruce-covered lands with permafrost at depths of 16 to 30 inches and
the willow-
^
^
and alder-covered lands without permafrost in the subsoils is
a very sharp one. The apparent reason for the differences in the perma–
frost level and in the vegetation is the annual flooding which takes
place on the lands with high water tables.
The unfrozen soils which owe their condition to topographic aspect
are of particular interest, inasmuch as they may indicate the type of
profile development which would be dominant in the region if permafrost
were not so prevalent. These soil
d
^
s
^
occupy some steep south-facing slopes,
and slopes along the breaks of rivers where drainage conditions are par–
ticularly good and where the tree cover is sparse enough to allow the
sunshine to penetrate to the ground. Consequently, these soils occur
only on sites that are
[:
]
drier than is normal for the region. These
sites usually have a considerable amount of grass under the forest cover,
the prevailing ground cover of moss being generally absent.
EA-PS. Leahey; Soils of Arctic Canada
A soil profile examined on the top of one of the breaks of the
Mackenzie River at about 67° N. latitude is fairly typical of the
profiles found on these unfrozen soils. A brief description of this
profile is given below.
|
Depth, inches
|
Description of material
|
pH
|
|
0-5
|
Reddish-brown clay loam
|
7.2
|
|
5-12
|
Yellowish-brown clay loam
|
7.4
|
|
Below 12
|
Gray clay loam, apparently
the parent material
|
8.6
|
No calcium carbonate was found down to the 12-inch depth. The
parent material, however, was strongly calcareous.
Factors Affecting Soils
As the zonal soils of the arctic region in Canada show only weak
profile development, the kinds of soil found there depend primarily on
the nature of the mineral parent material. However, the other factors
of soil formation, namely, climate, vegetation, topography, and age, have
all had some influence on the soils. The following discussion of the
effect of these different factors on the soils of the arctic region must
necessarily be speculative owing to the limited knowledge available con–
cerning the nature of these soils.
Climate.
The arctic region differs widely in climate from place to
place. The forested section in the Canadian Northwest is a region of
fairly warm summers and very cold winters, while the north and northeast
tundra section has generally cool summers and cold winters. Precipitation
varies from about 12 inches annually in the forested belt to a low of
about 7 inches along parts of the arctic coast. These climatic differences
EA-PS. Leahey; Soils of Arctic Canada
have had a tremendous influence on the nature of the vegetation, but in
themselves they do not appear to have affected to any great extent the
zonal soils within the region.
Vegetation
. Marked difference in vegetation, as, for instance, a tree
cover as compared to a treeless tundra cover, do not appear to have any
appreciable influence on the nature of the mineral soils. It has been
mentioned previously that the soils covered by forest showed somewhat
greater profile development than those from the tundra of northeastern
Canada. However, this difference may be due more to climate than to
vegetative cover, as in the Mackenzie Valley soils on similar parent
material do not appear to be influenced by the t
o
^
y
^
pe of vegetative cover.
Apparently where the subsoils are permanently frozen, the type of natural
vegetation has little influence on soil development.
Parent Material.
As climate and vegetational influences on soil for–
mation have been at a minimum in the arctic region, the kind of mineral
soils occurring there is dependent on the geological nature of the surface
deposits. Although the region was glaciated, the nature of the glacial
drift, in most cases, is closely related to the bedrock on which it lies.
Thus there are many kinds of surface deposits in this glaciated part of
Canada. In addition there are various kinds of alluvial deposits which
were brought into the region by some of the major rivers,
^
and
^
also residual,
colluvial, and quite likely some loessal soils, particularly in unglaciated
sections of the Yukon. Altogether there are a great variety of surface
deposits in this region of Canada and, therefore, a great variety of soils.
Topgraphy.
The effect of topography is of great importance in the
arctic region in that it has a considerable influence on the distribution
EA-PS. Leahey; Soils of Arctic Canada
of organic and mineral soils. In those areas where the climate pe
m
^
r
^
mits
a rapid growth of mosses, such as occurs in the forested section,
organic
soils occurs in the forested section,
organic soils occupy all the de–
pression
^
s
^
except those filled with water, cover the lower slopes leading
up from the depressions, and also cover most of the level land. In face
mineral soils are usually found only where the surface drainage is good.
The aspect of the slopes is also of great importance, as many steep north–
facing slopes may be covered entirely with organic soils. The writer has
^
author O.K.? (
^
observed some quite steep north-facing slopes to be entirely covered with
peat. In the central part of the Yukon it is not uncommon to find organic
soils with permafrost at shallow depths on the north-facing slope of a hill,
while mineral soils without permafrost are found on the south-facing slope.
In those parts of the Arctic where rigorous climatic conditions
prevent the rapid accumulation of peat, topographic position and aspect do
not appear to be of such great importance in governing the distribution
of organic and inorganic soils. It would appear that under these climatic
conditions organic soils are chiefly found in depressions, and that they
cover only a relatively small proportion of the land surface.
Age
. While soil-forming processes are exceedingly slow and in fact none
of the soils are very old in point of time, the oldest dating from the last
ice age, yet there are considerable differences between the alluvial soils
of Recent age of the Mackenzie and Yukon rivers and the soils developed
on the alluvial material these rivers deposited when they were forming
their present valleys. Whether these differences are attributable to
differences in age, or
,
to differences in the kind of material they deposited
at various stages in their development, is not kn
wo
^
ow
^
n. If they are due
EA-PS. Leahey; Soils of Arctic Canada
to age, then more chemical changes will have taken place in the older
soils than are suspected at the present time.
Permafrost
appears to be one of the principal factors limiting soil
development in the arctic region
^
^
of Canada. In many places the weak
development of the soil profiles could be attributed to the cool, dry
summers, a scanty vegetative cover, the nature of the parent material, or
a combination of these factors, as well as to the presence of permafrost.
However, in other sections, as for instance the forested part of the
Mackenzie Valley, permafrost appears to be the only factor restricting
profile development. The presence of permanently frozen subsoils greatly
decreases, if it does not prevent, the leaching of the mineral matter.
The rate of chemical weathering may also be slowed down by the coolness
imparted to the thawed upper part of the soils by the underlying frozen
layers.
Observations made in Canada indicate that where permafrost occurs it
is usually found near enough to the surface to affect soil development.
The shallow depth down to permafrost in most soils appears to be due in
part to the low precipitation and in part to the organic surface layer, as
the soils can be thawed out to a greater depth
by either
^
either by
^
applying water or
by clearing away the organic cover. Other conditions being the same, the
depth to the frozen subsoils can be related to the thickness of the organic
cover. For example at Fort Norman, Northwest Territories, observations made
on August 15, 1945, showed that under a 3-inch organic layer the mineral soil was
thawed to a depth of 29 inches while under a 6-inch organic layer it was
thawed to a depth of 20 inches. An adjacent peat soil was frozen at a depth of
only 11 inches. Total destruction of the organic cover by cultivation results
EA-PS. Leahey; Soils of Arctic Canada
in a lowering of the permafrost level from 1 to 3 feet in the Mackenzie
Valley. These observations suggest that the low precipitation is more
responsible for the high level of permafrost in some parts of Canada
than the presence of an organic surface layer.
Zones and Subzones
On the basis of broad differences in climate and vegetation the
arctic region of Canada may be divided into zones, each of which may be
divided into a number of subzones on the basis of the nature of the under–
lying rock formations.
Major Zones
The area underlain by permafrost in Canada may be divided into a
subarctic zone and an arctic zone; the subarctic zone being the forested
section and the arctic zone the treeless tundra region. The boundary
between these two zones is well defined, as the transition from forest to
tundra is usually a fairly sharp one.
Although the zonal soils of the subarctic and arctic zones are of the
same genetic type, they differ somewhat in their degree of development.
However, two other differences between the soils of the two zones are of
equal or greater importance: the proportion of the land surface that is
covered with bare rock and soils almost barren of vegetation is considerably
greater in the arctic than in the subarctic zone, while the proportion of
the land covered with organic soils is much higher in the latter zone.
The subarctic zone has a high proportion of its surface covered with organic
soils, while the arctic zone as a whole has a low proportion of such soils.
In both the subarctic and arctic zones there are major differences
EA-PS. Leahey; Soils of Arctic Canada
in the underlying rocks which are directly correlated with the kind of
soil parent material, the local topography, and the geographic pattern
of the different soils. These major differences in rock formation corres–
pond closely, but not exactly, to the major physiographic regions, and
therefore the boundaries of the subzones do not exactly correspond to
those of the major physiographic divisions.
Subzones
Four major subzones which occur in both zones can be identified: the
Canadian Shield, the Paleozoic limestone rocks of the Arctic Archipelago
and the Interior Plains region, the Cretaceous rocks of the Interior Plains
region, and the Cordilleran region.
Canadian or Pre-Cambrian Shield.
Although the general relief of the
Canadian
[:
]
Shield is low, the areas underlain by its rocks have an
irregular topography consisting of low hummocky hills separated by depressions
which are commonly occupied by lakes or muskegs. Glaciers moving over these
hard rocks did not p
ci
^
ic
^
k up or deposit any great load, and consequently the
soil mantle is very thin or absent in numerous places. As centers of
continental glaciation were located in this region, the soil mantle was
derived only from the pre-Cambrian rocks. The mineral soils in the Canadian
Shield are usually coarse in texture, consisting mainly of stony till,
gravels
^
,
^
and sands. Clay may occur locally in small areas. These soils
are somewhat acid in reaction.
E
Paleozoic Limestone Areas.
Areas underlain by Paleozoic limestones
are found in the islands of the Arctic Archipelago and in parts of the
Interior Plains region which extends up the lowlands of the Mackenzie River.
These areas vary in relief from level plains to mountains on some of the
EA-PS. Leahey; Soils of Arctic Canada
islands. The soil mantle varies considerably in thickness but on the
whole it is apt to be thin. As the soils on these areas have been derived
largely from the underlying rocks, they are usually highly calcareous
and strongly alkaline in reaction.
Cretaceous Areas
. Several large areas of Cretaceous rocks occur in
the northern extension of the Interior Plains region. Such rocks
^
are
^
for the
most part relatively soft shales. The relief varies from gently rolling to
hilly, the local topography being somewhat irregular but typical of a
youthful morainic surface. The soil mantle is usually fairly thick and
very little bare rock is exposed at the surface. The soils are fine in
texture except where material from harder rock formations has been
carried in by the glaciers. Dominantly, however, the soil mantle has been
derived from the soft underlying rocks. The reactions of the soils in this
area vary from weakly acid to a
k
^
l
^
kaline, depending on how much lime was
present in the parent rocks.
Cor
c
^
d
^
illeran Region.
This mountainous and dissected plateau region
presents a complex pattern of relief, local topography, and soil parent
material. Materials from many different kinds of rocks have contributed
to the surface deposits. The mode of deposition of the soil parent material
is much more complex than in the other subzones. This is due in part to the
rugged topography and in part to the fact that a considerable portion of the
region was not glaciated. In the glaciated areas most of the soils are coarse–
textured, while in the unglaciated portion most of the soils are medium–
textured and many of them are relatively free of stones.
Recent Alluvial Soils
. While occupying areas too small to be shown on
a small-scale map, these deposits are of particular importance to man as they
EA-PS. Leahey; Soils of Arctic Canada
occur in some of the most accessible parts of the arctic region. The
alluvial lands found along the Mackenzie and Yukon rivers and their
tributaries are of particular importance as they are generally of good
quality, occur where climatic factors make it possible to grow certain
garden and field crops, and are readily accessible. These alluvial soils
vary in texture from fin
d
^
e
^
, sandy loams to silt loams, contain considerably
more organic matter than the adjacent upland miner
s
^
a
^
l soils, and are almost
invariably alkaline in reac
g
^
t
^
ion. Alluvial soils also occur along the rivers
in the pre-Cambrian and Paleozoic areas but as far as is known they are
there less extensive and of much poorer quality than those which have been
mentioned.
EA-PS. Leahey; Soils of Arctic Canada
BIBLIOGRAPHY
1. Feustel, C., Dutilly, A., and Anderson, M.S. “Properties of soils
from North American arctic regions,”
Soil Sci.
vol.48,
pp.283-99, Sept. 1939.
2. Jenness, J.L. “Permafrost in Canada,”
Arctic
vol.2, pp.13-27, Sept. 1949.
3. Leahey, A. “Characteristics of soils adjacent to the Mackenzie River
in the North West Territories of Canada,”
Soil Sci
^
Soil Sci
^
. Soc.
Amer.
Proc
. vol.12, pp.458-61, 1947.
4. ----. “Factors affecting the extent of arable lands and the nature
of the soils in the Yukon Territory,” Pacific Sci. Congr.
7th, 1948.
Paper
delivered in New Zealand. As yet
(Dec. 1950) available only from the author in mimeographed
form.
A. Leahey
Soils of Greenland
EA-Plant Sciences
(Tyge W. Böcher)
SOILS OF GREENLAND
CONTENTS
|
|
Page
|
|
Introduction
|
1
|
|
Conditions of Temperature of the Soil
|
1
|
|
Structure of the Soil
|
2
|
|
Chemical Conditions of the Soil
|
4
|
|
Soil Microfauna
|
6
|
|
Soil Bacteria
|
6
|
|
Bibliography
|
7
|
EA-PS. Böcher: Soils of Greenland
TEXTS FOR FIGURES
|
Fig. 1.
|
Stone circles in stone-polygon soil in the valley at Cape
Daussy, East Greenland, lat. 69° 44′ N. -T.W. Böcher phot.
|
|
Fig. 2.
|
Moss tussocks with
Salix herbacea-Carex rigida
on bottom of
a valley snow-covered in winter. Tugtilik in East Greenland,
lat. 66° 20′ N. -T.W.Böcher phot.
|
|
Fig. 3.
|
The Blosseville coast at Cape Barclay in East Greenland, lat. 69°
14′ N. Scree of basalt blocks alternating with clayey areas and
solifluction soil (
Streifenboden
with stone rows). -T.W.Böcher phot.
|
|
Fig. 4.
|
Sandflugtsdalen in West Greenland, lat. 67° N. In the middle of
the picture embryonal dunes. In the background loess-covered
slope with low willow scrubs and dry steppe-like patches of
vegetation. -T.W.Böcher phot.
|
|
Fig. 5.
|
Variation in hydrogen ion concentration and electric conductivity
(Lt) in soils from Southwest Greenland. Ordinate: percentage
frequency. - After Böcher 1949 b.
|
|
Fig. 6.
|
Dried up and cracked saline soil on shore of saline lake. West
Greenland, lat. 67° N. -T.W.Böcher phot.
|
Note: The author submitted the above photographs for possible use as
illustrations. Because of the high cost of reproducing them as
halftones they will not be used. Meantime all photographs are
being held at The Stefansson Library
EA-Plant Sciences
(Tyge W. Böcher)
SOILS OF GREENLAND
Introduction
The following survey is intended as a short report on the information
about Greenland soils available at present and should not be considered an
attempt at a general account of Greenland pedology. Our knowledge of the
soils in Greenland is still very deficient, and unfortunately the plant
sciences section of the Encyclopedia Arctica is being prepared shortly
before the conclusion of important pedological investigations made on recent
Danish expeditions to Northwest and Northeast Greenland, including Peary
Land. With the exception of a very small number of papers, the literature
on the soils of Greenland has been written by botanists who started soil
investigations as part of the analysis of ecological factors.
Conditions of Temperature of the Soil
In early botanical literature (e.g., Kruuse 1898, p. 389) there are
reports on some measurements of soil temperature made on single days at
different depths and in different vegetations. Recent papers include reports
on observations for longer periods (see especially Sørensen, 1935 and 1941).
Poser’s paper of 1932 deals with investigations of permanently frozen soil
(in which there are parallel horizontal flakes of pure ice up to a thickness
of 2 cm.) and of the soil thawing in summer and its depth in proportion to
EA-PS. Böcher; Soils of Greenland
The distance from perennial snowdrifts or the ice-foot along the coast of
sea and fjord. Sørensen’s Plate 13 (1941) gives a very interesting graphic
representation of the temperature series for air, soil surface, and soil at
depths of 60 and 100 cm. and of the thickness of the snow cover in the
period September 1934 to August 1935 at Eskimonaes in Northeast Greenland.
Böcher’s investigations (1949) include surface temperature in continental
West Greenland in August 1946. A south-facing loess soil there had a mean
maximum temperature of 29°C. and an absolute temperature of 50°C., while
corresponding values for a level moist humus soil were 12° and 20°.
Structure of the Soil
Solifluction phenomena have been studied particularly. Poser (1932)
classifies the arctic type of soil as: (
1
)
Strukturboden
, solifluction soil,
including (a) Steinnetzwerk, stone-polygon soil, and (b) Streifenboden,
stone-row soil developed by solifluction; (
2
)
Frostspaltenboden
, developed
by contraction of the soil under very great cooling; and (3)
Pflasterboden
(or Schuttglättung) gravelly flats or surface formed by closely packed
pebbles in depressions which for the greater part of the year are covered
by large masses of snow.
Sørensen (1935) takes up the problem of solifluction in itself for
thorough discussion and in this connection, besides measurements of tempera–
ture, deals with alayses of particle-size distribution (according to Atterberg)
in sandy and clayey solifluction soils. His Table 4 is a survey of the high–
arctic solifluction forms in their relation partly to the snow cover and the
content of water in the soil and partly to the sloping and homogensity of the
soil (fine-grained soil with or without stones or without stones or blocks).
EA-PS. Böcher; Soils of Greenland
A good example of a Greenland solifluction soil on level ground (stone–
polygon soil) is seen in Figure 1. Investigations of the relation of
vegetation to solifluction are reported in Seidenfaden, 1931; Böcher, 1933;
Seidenfaden & Sørensen, 1937.
Clayey soils
are widely distributed, particularly as parts of the
complex solifluction soils (
Strukturboden
) mentioned above, and particularly
occurring in typically arctic parts of Greenland. Furthermore deposits of
clay, often of considerable extent, are found at the heads of such fjords
as do not end in calving glaciers, but to which rivers flow from the edge
of the inland ice. Very considerable areas with bluish-gray are found, for
example, at the head of the Søndre Strømfjord. The dry parts of these
deposits of clay provide very bad conditions for vegetation, as the soil
becomes very hard, with deep crevices.
Loess Soils.
The West Greenland loess soils in the continental area
at the edge of the inland ice about latitude 67° North were first investi–
gated by Nordenskjöld (1914, p. 518), who provides an Atterberg analysis of
particle-size distribution in a single soil and compares it with other loess
soils outside Greenland. Further investigations of the particle sizes in
loess and sandy soils in this area are reported in Böcher (1949 b).
Drift-sand areas
of fairly large extent have been recorded by Hartz and
Kruuse (1911) from Hurry Inlet at Scoresby Sound. There are fairly consider–
able areas of dunes there in connection with stony plains that have arisen
by the sand being transported away. Considerable inland dune areas are
found in connection with the large river valleys in the continental regions
of West Greenland. See further Böcher 1949 a and b and Figure 4.
Gravelly Soils
. Very coarse-grained gravelly soils, unfavorable to
EA-PS. Böcher; Soils of Greenland
vegetation, arise by weathering of gabbro in the Kangerdlugssuaq area in
East Greenland, where large stretches are covered by sharp-edged gravel
without vegetation (Böcher, 1933). About Angmagssalik, too, there are
large areas with gravelly soil, the size of grains of which is between
2 and 200 mm. (Kruuse, 1912). From the coarsest gravelly and stony soils
there is an even transition to the block areas which are particularly found
in acres and which, for example, in the basalt regions of East Greenland
have an enormous distribution. The lowest part of the mountains up to
heights of about 200 to 300 meters above sea level may consist mainly of
large angular blocks (Fig. 3).
Humus Soils
. Special investigations of the content of humus in the
Greenland soils have not been recorded. Characteristic humus soils are
particularly found in South Greenland. There is no large-scale formation
of peat. In South Greenland we may come across bogs with rather high
tussocks formed by
Sphagnum
and
Aulacomnium
. Peat is formed as far north
as Angmagssalik district on the east coast and in the Disko region on the
west coast, in the north mostly a marsh peat of slight thickness with ample
admixture of mineral particles. Many soils under dwarf shrub heaths in
southern Greenland are nearly pure humus soils. Farther north the admixture
of minerals even in heath soils is nearly always fairly great.
Chemical Conditions of the Soil
So far these have particularly been investigated in Southwest Greenland
(Böcher, 1949 b). Very great differences have been discovered between soils
from the coastal areas and soils from the inland, particularly the continental
area about latitude 67° North. A general survey of the distribution of
EA-PS. Böcher; Soils of Greenland
hydrogen ion concentrations and values for electric conductivity in
oceanic and continental regions is given in Figure 5. Even typical
humus soils in the continental area have no pH below 4.8, which is due
to less leaching and admixture of loess particles. The highest pH values
and values of electric conductivity are recorded from saline soils. Such
soils are of course found by the sea, particularly in salt marshes, (cf.
Madsen, 1936, pp. 35-41), but have also been found in the inland around
lakes without any outlet and on south-facing slopes covered with loess.
The continental saline soils have been made the objects of particularly
thorough chemical analyses. A percentage sodium-potassium saturation of
17 and a pH of 8.9 were found on a south-facing slope where salt crusts
were formed on the ground because of an upward movement of the water.
Similar values were found in the salt lake depressions. In a single place
there was even a genuine alkaline soil with pH 9.2 and a sodium-potassium
saturation of 25 per cent.
Some measurements of potassium values and phosphoric acid values in
various Greenland soils have been recorded in Böcher 1949 b. These are
generally high as compared with the values of Danish soils. No special
investigations of cultivated soils in Greenland have been recorded.
Manured soils occur everywhere around villages and outlying settlements
and around many ruins of Eskimo houses; also, below bird cliffs and in
resting places of various animals. Cultivated soil (cultivated grass
fields, potato fields, fields of spring corn, gardens near houses) is
mainly found in southernmost Greenland.
The occurrence of soils in the regions of basalt and Archean rock
is of great significance for our understanding of many distributions of
EA-PS. Böcher; Soils of Greenland
of plants in Greenland. A number of acidophilous plants completely
avoid the basalt, or are very rare and selective within the basalt areas;
see the section on “Edaphic Distributions” in my article on “Flora and
Vegetation in Greenland” in the Encyclopedia Arctica.
Soil Microfauna
Comprehensive investigations based upon Berlese tests of the micro–
fauna in the soil (particularly orbatid and collembole fauna) have been
made by Jørgensen 1934 a and b, M. Hammer 1937, 1944, and Hearløv 1942.
These investigations have been made in different plant communities, and
therefore in soils with highly different conditions for the fauna.
Soil Bacteria
Special investigations of the soil microflora have been made on
Disko Island in West Greenland by C. Barthel (1922). Fourteen very different
samples showed a great uniformity with regard to the species content, and
the similarity between the Greenland soil flora and that of Europe (France)
was found to be very great. On the occurrence of tubercle-forming bacteria
of the Leguminosae, see Nielsen (1928) and Porsild (1929) On sulphur
bacteria in salt marsh soils, see Madsen (1936).
EA-PS. Böcher; Soils of Greenland
BIBLIOGRAPHY
1. Barthel, C. 1922. “Recherches bactëriologiques sur le sol et sur les
matieres fëcales des animaux polaires du Groëland septenrionale.”
Meddelelser om Grønland
, vol. 64, pp.1-76.
2. Böcher, T.W. 1933. “Studies on the Vegetation of the East Coast of
Greenland between Scoresby Sound and Angmagssalik.”
Meddelelser
om Grønland
, vol.104, no.4.
3. ----. 1949a. “The Botanical Expedition to West Greenland.”
Meddelelser
om Grønland, vol.147, no.1
4. ----. 1949b. “Climate, Soil, and Lakes in Continental West Greenland in
Relation to Plant Life.”
Meddelelser om Grønland
, vol.147, no.2.
5. Haarløv, N. 1942. “A morphologic-systematic-ecological investigation of
Acarina
.”
Meddelelser om Grønland
, vol.128, no.1
6. Hammer, M. 1937. “A quantitative and qualitative investigation of the
microfauna communities and
of the soil at Angmagssalik and in
Mikifjord.”
Meddelelser om Grønland
, vol.108, no.2.
7. ----. 1944. “Studies on the Oribatids and Collemboles of Greenland.”
Meddelelser om Gønland
, vol.141.
8. Hartz, N. & Kruuse, C. 1911. “The Vegetation of Northeast Greenland.”
Meddelelser om Grønland
, vol.30.
9. Jørgensen, M. 1934. “A quantitative investigation of the Microfauna
Communities of the Soil in East Greenland.”
Meddelelser om
Grønland
, vol.100, no.9.
1)0
^
10.
^
Kruuse, C. 1898. “Vegetationen i Egedesminde Skaegaard.”
Meddelelser
om Grønland
, vol.14.
11. ----. 1912. “Rejser og botaniske Undersøgelser i østgrønland samt
Angmagssalikegnens Vegetation.”
Meddelelser om Grønland
, vol.40.
12. Madsen, H. 1936. “Investigations on the shore fauna of East Greenland
with a survey of the shores of other arctic regions.”
Meddelelser
om Grønland
, vol.100, no.8.
13. Nielsen, N. 1928. “Gibt es Knölchenbakterien auf Disko in Grönland?”
Dansk Botanisk Arkiv
, vol.5, no.19.
14. Nordenskjöld, O. 1914. “Einige Zűge der physischen Geographie und der
Entwickelungsgeschichte Sűd-Grönlands.”
Geographishe Zeitschift
,
vol.20, Heft 8, pp.425-641. Leipzig.
EA-PS. Böcher; Soils of Greenland
15. Porsild, M. P. 1929. “Gibt es es Knöllchenbakterien auf Disko in
Grönland?”
Dansk Botanisk Arkiv
, vol.6, no.7.
16. Poser, H. 1932. “Einige Untersuchungen zur Morphologie Ostergrönlands.”
Meddelelser om Grønland
, vol.94, no.5.
17. Seidenfaden, G. 1931. “Moving Soil and vegetation in East Greenland,”
Meddelelser om Grønland
, vol.87, no.2.
18. ----., and Sørensen, Th. 1937. “The Vascular Plants of Northeast
Greenland from 74°30′ to 79°00′.”
Meddelelser om Grønland
,
vol.101, no.4.
19. Sørensen, Th. 1935. “Bodenformen und Pflanzendecke in Nordostgrönland.
Beiträge zur Theorie der polaren Bodenversetzungen auf Grund von
Beobachtungen über deren Einfluss auf die Vegetation in Nordos–
grönland.”
Meddelelser om Grønland
, vol.93, no.4.
20. ----. 1941. “Temperature Relations and Phenology of the Northeast
Greenland Flowering Plants.”
Meddelelser om Grønland
, vol.125.
Tyge W. Böcher
Soils of Svalbard and Northernmost Europe
EA-Plant Sciences
(Gunnar Holmsen)
SOILS OF SVALBARD AND NORTHERNMOST EUROPE
CONTENTS
|
|
Page
|
|
Permanently Frozen Soil
|
1
|
|
Soil Profile
|
3
|
|
Frost and Solifluction
|
6
|
|
Surface Markings
|
7
|
|
Springs
|
9
|
|
Ground Ice
|
9
|
|
Bibliography
|
12
|
EA-Plant Sciences
(Gunnar Holmsen)
SOILS OF SVALBARD AND NORTHERNMOST EUROPE
PHOTOGRAPHIC ILLUSTRATIONS
With the manuscript of this article, the author submitted 11 photo–
graphs for possible use as illustrations. Because of the high cost of
reproducing them as haltones in the printed volume, only a small propor–
tion of the photographs submitted by contributors to
Encyclopedia
Arctica
can be used, at most one or two with each paper; in some cases
none. The number and selection must be determined later by the publisher
and editors of
Encyclopedia Arctica
. Meantime all photographs are being
held at The Stefansson Library.
EA-Plant Sciences
(Gunnar Holmsen)
SOILS OF SVALBARD AND NORTHERNMOST EUROPE
Permanently Frozen Soil
According to a definition frequently used by phtogeographers, a
climate is considered arctic when the July isotherm is below
^
+
^
10°C. (50°F.).
By this definition, only the northernmost coastal strip of Norway can be
called arctic, and nowhere in the country does such a climate extend as far
south as latitude 70° N. The development of vegetation is mainly influenced
by the summer temperature, while the qualities of the soil depend largely on
the low winter temperatures.
In areas with extremely cold winters, as for instance northern Siberia,
even quite warm summers fail to thaw frozen ground. The temperature of the
ground in summer in areas of this type is 2 to 3°C. below the freezing point
of water. In mountain regions the permanently frozen soil extends farther
south than near the sea. Thus, a frozen moraine more than 20 meters deep was
discovered near the Moskogaisa mines, 1,000 meters above sea level at 69°30′
N. latitude.
Inland on the Scandinavian Peninsula there are uplands where the soil
stays frozen throughout the summer. Even as far south as latitude 62°07′ N.,
layers of permanently frozen soil were found underneath the turf during railway
building at Dovrefjell. The layer was encountered at an altitude of 948 meters
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
above sea level and extended several meters below the surface. Turf hillocks
that never thaw are known in northern Norway, Sweden and Finland, in the Kola
Peninsula, and in the tundras of the Soviet Union. East of Archangel the
eternally frozen soil occurs as far south as the Arctic Circle, while in
the Ural Mountains it extends even farther south.
As we travel south, we must climb higher and higher in the mountains to
encounter conditions which may be considered similar to those of the Arctic.
In the mountains of the Scandinavian Peninsula are found soil structures
characteristic of the polar regions, such as tundra polygons, hillock fields,
and solifluction tongues.
In European U.S.S.R. the dry tundras with permanently frozen soil stretch
along a narrow coastal strip in the north. From this belt southward to the
forest region scientists have noted a swampy tundra with occasional frozen
peat hillocks underneath the thawed surface layer.
In arctic areas the frozen substratum lies close to the surface. The
depth of the frozen layer depends on winter temperature and snow cover.
Extreme cold and a scanty cover of snow may result in frozen earth hundreds
of meters deep. The thickness of the thawed top layer to which water circu–
lation is confined is very slight. As the dissolved matter in soil water is
not transported to the depths, soil profiles like those of humid regions
cannot be formed in the Arctic. The saturation of the surface layer greatly
facilitates solifluction, even on only moderation sloping fields. Also, this
saturated layer on top of the dry frozen earth is an essential condition for
the formation of surface markings. These characteristic arctic phenomena
are the result of the frozen substratum, low evaporation, and sparse vegetation.
In Svalbard the frozen layer attains a depth of hundreds of meters. The
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
few measurements that have been made offer interesting information. A deep
drilling on Bear Island disclosed a layer of frozen material 75 meters
thick. The frozen layer in the flat Spitsbergen valleys is of a similar
thickness, while in mines higher above sea level it is considerably thicker.
Thus the Sofie mine, Kings Bay, is frozen to a depth of 150 meters, while the
rock temperature in the Svea mine, Bell Sound, only attains 0°C. at a depth
of 320 meters below the surface and at a distance of 430 meters from the
mine opening.
Soil does not freeze underneath large glaciers, fjords, and great lakes.
The frozen zone may, however, creep as much as 200 meters inward from the
edge under large glaciers. The absence of frost under glaciers was proved
by H. U. Sverdrup, who measured temperatures on the Fourteenth of July Glacier
in 1935.
Among the polar countries, Svalbard is the one most extensively surveyed
geologically. During the second half of the nineteenth century, Swedish
explorers performed outstanding pioneer work which has been carried on into
the twentieth century. During the early part of this century, Norwegian
researchers participated in the scientific mapping expeditions of Prince
Albert I of Monaco. These were succeeded by a number of Norwegian expeditions
partly financed by the state. Since the Svalbard treaty was put to effect
in 1923, the investigation of Spitsbergen and Bear Island has been conducted
by the Polar Institute, a Norwegian state institution, or its predecessors.
Soil Profile
The facts about the soils of Svalbard given in this article are valid
also for the alpine regions of northernmost Europe.
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
In the Svalbard climate, mechanical weathering far exceeds chemical
weathering. Colloidal matter is therefore sparsely represented in the soil,
mineral absorption from which is consequently low. Humus deposits are
inconsiderable. Because of the scanty vegetation and the constantly frozen
layer underneath, the conditions for peat formation are unfavorable. Small
areas of tundra swamps, however, occur in large flat-bottomed valleys.
K. C. Björlykke examined some Spitsbergen and Bear Island soil profiles
to a depth of 50 centimeters. One sample from Hjorthamn, Advent Bay, con–
sisted of river mud in wh
c
^
i
^
ch the find sandy fraction (of particles 0.2 to 0.02
millimeters in diameter) was dominant. The
^
phosphorous pentoxide
^ (P2O5)
and
[:
]
^[:
]^
potassium oxide (K
2
O
5
) contents were equal in the upper horizon (A) and in the
[:
]
under layer (C), while the underlayer was somewhat richer in calcium
oxide (CaO) and ferric oxide (Fe
2
O
3
) than the A horizon. While the A horizon
shows a practically neutral reaction of pH 6.54, the C horizon is slightly
acid, being pH 6.11. Thus the analyses does not indicate noteworthy
chemical weathering.
Another sample, from Ny-Aalesund in Kings Bay, was taken from a marine
terrace, the surface of which consisted of pebbles and gravel with some
finer material gradually passing into marine clay with mussel shells toward
the lower depths. The terrace was barely covered with scanty vegetation
consisting of mosses and lichens,
Salix polaris
, and a few flower species.
The underlayer as well as the upper one showed a slightly acid reaction -
pH 5.76 and 5.53, respectively. Chemical analysis proved that the upper and
under layers contained nearly the same amount of potassium and iron, and even
phosphorus and calcium. Thus, chemical weathering is not much in evidence in
Svalbard. There is little or no difference between the upper and under layers.
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
Indeed, the surface deposits of Svalbard correspond in their entirety to
the underlayers of regions farther south. The profiles, consequently, show
no actual soil formation.
Among the three Bear Island samples examined, one showed an A horizon
richer in P
2
O
5
, K
2
O, and CaO than the C horizon, the pH being 7.72 and 8.39,
respectively. The second profile contained equal amounts of P
2
O
5
and K
2
O in
the two horizons, while the C horizon contained more CaO and Fe
2
O
3
than did
the A horizon. The third sample also showed relatively stable contents of
phosphorus and potassium at the lower levels, whereas calcium and iron
increased so considerably downward as to indicate the beginning of soil
formation. All the samples showed a strong alkaline reaction, and alkalinity
as well as calcium content increased with depth.
The upper layer of the third sample was highly humous. In this respect
it resembles the soils of humid regions, and Björlykke considers this sample
a transition
,
form between the sterile skeleton soil of Svalbard and the
soils of northern Norway.
E. Blanek has collected and examined a number of earth and rock samples
from the Ice Fjord area. Chemical analysis of one rock in various stages
of weathering showed that calcium and iron contents are partially dissolved
during the weathering process, while the alkalis remain intact, consequently,
the water hydrolysis even demonstrated by Svalbard river water, in which
dissolved matter is very scarce.
In spite of the limited circulations of water in the frozen earth, salt
crystallization occurs at the surface in the wide Ice Fjord valleys. The
crystals may become so numerous as to make the ground appear covered with
hoarfrost. The salt consists of potassium sulfate, magnesium oxide, and
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
sodium carbonate, and the curst may attain a thickness of one centimeter,
though usually it is frail and thin, forming a mere veil. Damp air dissolves
it. The sale is derived from Tertiary shales and sandstone layers as well
as from Jurassic and Triassic layers.
Frost and Solifluction
Frost is an active agent of mechanical weathering. In arctic regions
this is apparent from the occurrence of great boulder fields on plateaus, of
talus formations, and of screes covering the slopes beneath rock exposures.
In the cold climate of Spitsbergen, flat block plains extend down to sea level,
while to the south in Europe they are encountered only at some height above
the sea (Fig. 1).
When freezing, water swells with enormous force. This process, repeated
again and again, wedges open the bedding planes and joints and even the pores
between individual particles or crystals. Frost may break sandstone and
coarse-grained eruptives into big blocks, and slate or fine-grained rocks
into a loose grit.
The recurrent disturbance through alternative wetting and drying, freezing
and thawing, causes both coarse and fine material to slide slowly downhill.
This surface creep or solifluction is a most important factor in helping
to determine the type and appearance of the soil in polar countries, where
the sparsely covered earth is frozen below the surface layer, which in summer
is sodden.
[:
]
Within the boundaries of the arctic climate, therefore,
stable soil is not as common as creeping soil (Fig. 2).
The peculiar arrangement of the material is a striking feature. Thus,
the weathering gravel may be ranged in parallel striped down the mountainsides
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
(stone stripes). Between bands of finer material, varying in breadth from
a few decimeters to a coupld of meters, there may be seen narrower stripes
of stone, sometimes slightly sunken. Vegetation, if any, is limited to these
stone stripes.
On moderately sloping hills the earth will sag into convex lobes. This
movement causes a mount to be accumulated at the foot of the sliding area,
such mounds sometimes attaining a height of about two meters. In summer
the mound may be pushed forward a few decimeters (Fig. 3).
Even in heavy block screes one may observe closely packed ridges which
have been formed by sagging. With repeated change of volume, the blocks
attain an unstable balance that leads to gliding.
In Spitsbergen, shales easily crumble into fine gravel. Unless the
debris is carried away by running water at the foot of the scree, it will
be caught by solifluction and distributed over the bottom of the valley (Fig. 4).
Surface Markings
Even on level plains, seasonal freeze and thaw will sort the earth on
top of the continuously frozen ground. The most extreme development of this
is encountered as a regular network of polygonal fissures filled with stones.
The polygons make a striking impression in the landscape, as may be seen in
Figure 5. Where silty soil occurs, the water-soaked layer between the surface
and the frozen ground will contract while drying, and in homogeneous material
fissures at an angle of about 120° will develop. In this manner hexagonal
polygons (Fig. 6). Occasionally two generations of polygons appear in one
locality, as may be seen in Figure 7. Inside the older, large polygons, which
commonly have a diameter of 8 to 10 decimeters, are the younger, small ones
with a diameter of only a few centimeters. The polygon fissures further the
EA-PS. Holmsen: Saoils of Svalbard and Northernmost Europe
draining of the soil as they constitute an outlet for the water. Vegetation
also profits by the fissures which offer good growing conditions.
On stony ground there are polygons, the boundaries of which are marked
by raised stone walls instead of the usual fissures. Where stones predominate,
the polygons look rather like circles bounded by more or less broad stone
edges, as illustrated by Figure 8. The sorting of stone materials is brought
about by frost. In the polygon
s
fissures, frost will press the stone toward
the surface. Since stone is a better conductor of heat than earth, and ice
will melt around and beneath it during the day. At night, when the water
freezes again, the stone will be pressed up through the surface where it
remains propped up by pebbles after the ice has melted. On sloping ground
are polygons, the form of which has been stretched out by the creeping surface.
Practically everywhere a keen observer will see signs of soil movement (Fig. 9).
Some polar plants get protection against evaporation by growing in matted
tufts. Where those plants occur on nearly stoneless earth they cause tundra
hillocks. Vegetation
[:
]
^
insulates
^
against changes of temperature, so the
stretches of bare ground between the tufted plants are particularly liable
to be penetrated by frost (Fig. 10).
When the earth freezes, an ice sheet will form under the hillock, pressing
it upward. Melting, the ice leaves its space to be filled up by underground
material in a manner similar to that which goes on in the stone polygons just
described. Repeated freezing and thawing, therefore, will add to the height
of the hillocks. On examination they consist of fine-grained mineral earth —
not, as might be expected, of turf.
Tundra hillocks occur on the high mountain plains of Scandinavia, though
at considerable altitudes. In central Norway, they are usually found at
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
1,100 to 1,200 meters above sea level.
Springs
In the autumn, long after frost has set in and most water has turned to
ice, streams still run from under the large glaciers. In Svalbard there are
also springs and subterranean watercourses, the relatively high temperature
of which indicates their source to be in frost-free earth below the frost
zone. The high temperature is especially marked in the large springs that
remain several degrees above the freezing point (up to
[:
−
^+^]
15°C.), and it is
probably owing to the greater quantities of water involved in these cases
that the temperature can remain so high in passing through the frost zone.
Many large springs appear in limestone channels, some of which may be associated
with dislocations.
In Bock Bay on the north coast of Spitsbergen, there are warm springs
whose temperature may remain as high as
−
^
+
^
28°C. These springs are limited to
a small area and are supposed to be of volcanic origin. The high temperatures
of numerous springs along the west coast, however, bear no relation to
[:
]
volcanic activity. The warm water must be a result of the increase of the
earth’s temperature at low levels. Water at a temperature as high as
−
^
+
^
15°C.
must originate from great depths, at least 500 meters below the frozen zone.
This is also indicated by the presence of dissolved silica and sodium in the
spring water. On analysis the water contains considerable amounts of salt,
which must be owing to admixture of deep-seated water.
Ground Ice
Layers of pure ice and earth alternate below the thawed top layer.
Such bedding of the soil is common in the great Spitsbergen valleys and has
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
also been described from most other arctic countries under such terms as
stone ice, fossil ice, or ground ice.
The botanist Hanna Resvoll-Holmsen was the first to observe the deep
layers of ground ice. From Coles Bay, where the spent the summer of 1908,
she described the occurrence shown in Figure 11. The terrace photographed
is 8 to 10 meters high, situated about 3 kilometers from the head of the bay,
and 30 meters above sea level, sloping from the mountainside toward the river
which curves below. Here the earth profile could be observed in three deep,
approximately parallel crevices. The crevice walls consisted of pure ice,
apart from the top layer of 80 centimeters which consisted of five different
layers. Resting on the ice were two peat layers of a combined
[:
]
depth
of 25 centimeters. The lower one consisted of moss peat, while the upper one
contained other plant remains as well, such as a large amount of
Salix polaris
leaves. Above the peaty layers lay 5 centimeters of silt, upon which rested
an equally deep layer of fine clayey gravel. The top layer was 40 centimeters
of mud. As the ice melted, the layers on top of it slid into the crevice,
covering the bottom with mud and so obstructing examination of the lower ice.
The visible part of the ice was clear, containing practically no earth. The
peat layers resting on ice appear to have been buried under a flow of solifluction.
The pure ice layers in the ground may attain a depth of a couple of meters.
Alternating with earth layers, they have been observed to a depth of 15 meters
below the surface.
There are many theories concerning the origin of
[:
]
ground ice as
known in regions with permanently frozen soil. The most acceptable explanation
is that in the autumn when frost sets in, the uppermost part of the thawed
soil is gradually transformed into a watertight cover of frozen earth while
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
freezing downward from the surface. Between this cover and the permanently
frozen earth below, an unfrozen bed may remain for some months during the
early part of the winter. In Antarctic Harbour, East Greenland, circulation
of water between the two layers has been observed from the middle of September
to the middle of December.
The circulating water will partly stay under hydrostatic pressure at the
lower levels of the hillsides until it freezes. Ground ice will be found in
the narrow space between the frozen surface layer and the permanently frozen
earth. Owing to the water pressure and the freezing of the water, the surface
may be raised considerably.
The occurrence and distribution of ground ice is limited to localities
where topography, soil, and water supply promote
[:
]
its formation. This
is the case in the lowlands along the slopes of the great valleys, where
water seeps down from patches of ice and snow until frost sets in. As might
be expected, the ice attains its greatest depth below these slopes. In the
plains far from the slopes, there are usually only small sheets of ice, if any.
The ground ice is normally built up from one year to the other, and thus
is mostly stratified with bands and patches of soil. When the water supply
is abundant, however, pure ice of considerable thickness may be formed during
one year.
As ground ice is formed in the lower part of the woil which has thawed
during the summer, the ice will follow the surface at slight depth, in Spits–
bergen varying from 10 centimeters where the insulation cover is particularly
effective, oown to 60 centimeters or even more. Where the thaw goes deeper,
as in several places in Siberia and in the arctic prairies of North America,
ice will be formed at even greater depths.
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe
BIBLIOGRAPHY
1. Bailey, E.B., and Weir, J.
Introduction to Geology
. London, 1939.
2. Beskow, Gunnar. “Soil freezing and frost heaving,”
Sveriges
geologiska Undersökning
, ser.C nr. 375, 1935.
3. Björlykke, K.O. “Bodenprofile aus Svalbard,”
Soil Research
, vol.1, 1928.
4. Blanck, E. “Die wissenschaftlichen Ergebnisse einer bodenkundlichen
Forschungsreise nach Spitzbergen im Sommer 1926,”
Chemie
der Erde
. Jena, 1928.
5. Flint, R.F.
Glacial Geology and the Pleistocene Epoch
. N.Y., London, 1942.
6. Holmsen, Gunnar. “Report on a geological expedition to Spitsbergen 1909,”
Bergens Mus. Årb. 1911.
7. ----. “Frozen ground along the Dovre railway,”
Naturen
, 1917.
8. ----.
Spitsbergens Natur og Historie
. Kristiania, 1911.
9. ---. “Spitsbergens jordbundsis,” Norske Geografiske Selskabs.
Årbog
, 1912.
10. ---. “Om jordlags langsomme glidning, solifluktion,” Norske Geografiske
Selskabs
Årbog
, 1913.
11. Huxley, J.S., and Odell, N.E. “Notes on surface markings in Spitsbergen,”
Geogr.J.
1924.
12. Högbom, Bertil. “Einige Illustrationen zu den geologischen Wirkungen
des Frostes auf Spitzbergen,” Geol.Inst. of Upsala,
Bull
.
vol.9, 1910.
13. ---. “Wustenerscheinungen in Spitzbergen,”
Ibid
. vol.11, 1912.
14. ---. “Uber die geologische Bedeutung des Frostes,”
Ibid
. vol.12, 1913.
15. ----. “Beobachtungen aus Nordschweden über den Frost als geologischer
Faktor,”
Ibid
. vol.20, 1921.
16. Lundqvist, G.
De Svenska Fjällens Natur
. Stockholm, 1948.
17. Magnusson, Granlund, and Lundqvist.
Sveriges Geologi
. Stockholm, 1949.
18. Meinardus, W. “Arktische Boden,”
Handbuch der Bodenlehre
, heraus–
gegeben von E. Blanck. Berlin, 1930.
19. Orvin, Anders K. “Hvordan oppstår jordbunnsis ?”
Norsk Geogr
.
Tidsskr
. 1941.
EA-PS. Holmsen: Soils of Svalbard and Northernmost Europe - Bibliography
20. ----. “Litt om kilder på Svalbard,”
Ibid
. 1944.
21. Resvoll-Holmsen, Hanna. “Om jordbunnstrukturer i polarlandene og
planternes forhold til dem,” Nyt Magazin for Naturvidenska–
berne, vol.47, 1909.
22. ---. “Om Spitsbergen Plantevekst,”
Naturen
, 1910.
23. Werenskiold, W.
Fysisk Geografi
. Oslo, 1943.
Gunnar Holmsen
Soils of the Eurasian Arctic.
EA-Plant Sciences
(C. C. Nikiforoff)
SOILS OF THE EURASIAN ARCTIC
CONTENTS
|
|
Page
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|
Geological Structure
|
1
|
|
Recent Glaciation
|
7
|
|
Surface Formations
|
10
|
|
Marine Sediments
|
10
|
|
Morainic and Fluvioglacial Deposits
|
10
|
|
Rock Land
|
10
|
|
Stony Land
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11
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|
Soil Characteristics
|
11
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|
Arctic Desert
|
12
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|
Tundra and Wooded Tundra
|
14
|
|
Eurasian Arctic Islands
|
14
|
|
Kolguev Island
|
16
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|
Novaya Zemlya
|
17
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|
Vaigach Island
|
20
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|
Severnaya Zemlya
|
21
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|
Novosibirskie Islands
|
22
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|
Wrangel Island
|
24
|
|
Smaller Islands of the East Siberian Sea
|
25
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|
Islands of the Kara Sea
|
26
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Mainland of the Eurasian Arctic
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27
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|
Bolshezemelskaia Tundra
|
32
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|
Iamal Peninsula
|
32
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|
Gydan Peninsula
|
33
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|
Taimyr Peninsula
|
34
|
|
Bibliography
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36
|
EA-Plant Sciences
(C. C. Nikiforoff)
SOILS OF THE EURASIAN ARCTIC
Geological Structure
Although geological structure of the Eurasian Arctic is little known,
the general trend of at least the most recent period of geological history
of this region gradually unfolds itself. It appears that in Pliocene time,
and, probably in early Pleistocene, the northern coast of the Eurasian
continent was located farther to the north than its present position. At
that time most of the arctic islands in the Eastern Hemisphere, with the
possible exception of Spitsbergen and Franz Josef Land, probably were not
separated from the mainland.
During the Pleistocene the western section of the northern part of
the continent was subject to at least two glaciations, of which the older
was more widespread and severe than the following. The later glaciation
is still in progress, although geological records show that it is in an
advanced stage of ablation. The ice shields on Spitsbergen, Franz Josef
Land, Novaya Zemlya, Severnaya Zemlya, and other arctic islands are shrink–
ing and represent the waning remnants of a greater glaciating which, however,
did not extend to the mainland, being confined to the islands.
During the earlier glaciation a large northern part of the west Siberian
lowland, the entire Taimyr Peninsula, and the area which is now occupied by
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
the Kara Sea and the western part of the Laptev Sea, including Novaya Zemlya,
Severnaya Zemlya, and other islands, presumably was covered by an immense
continuous ice sheet. The evidence of such a glaciation is the occurrence
throughout the glaciated part of the mainland of numerous erratic repre–
senting the rocks of Novaya Zemlya.
It is believed that sometimes during this period the broad coastal belt
of the continent was depressed below seas level whether because of the heavy
load the continent was depressed below sea level whether because of the heavy
load of ice or owing to the general epeirogenic processes. Thus, melting of
the ice was accompanied by the encroachment of the sea upon the land. The
greater part of the inundated lowland is still under water.
The continental shelf of Eurasia varies in width from about one hundred
miles to more than three hundred miles. Its northern boundary has not yet
been mapped along its entire length. The depth of the sea increase sharply
at this margin from a few hundred feet to several thousands of feet.
The highest mountains scattered throughout the shelf never were completely
submerged, and formed islands including Spitsbergen, Franz Josef Land, Novaya
Zemlya, and others, which originally were smaller and fewer than the present
islands. Older islands were enlarged and now ones such as Kolguev and Belyi
were formed by the subsequent uplift of the region and emergence here and
there of the sea bottom. Thus, the low coastal flats adjacent to the rocky
and rather craggy older parts of the islands rose above sea level.
That the uplift of the region followed marine ingression is clearly
shown by a series of well-preserved marine terraces on the shores of the
arctic islands as well as on coast of the mainland. These terraces
are covered by marine sediments containing fossils of marine fauna, largely
mollusks, showing little or no difference from the contemporary fauna of the
Eurasian arctic seas.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
The highest known marine terraces on the north coast of the Taimyr
Peninsula have an elevation of 360 feet (Berg). Similar terraces on
Novaya Zemlya are much higher; on the southern island some of them have
elevations of about 800 feet, whereas on the northern island remnants of
terraces were found considerably above the 1.000-foot contour. According
to Weise, some of them have an elevation of 420 meters, i.e., about 1,378
feet. On Severnaya Zemlya some marine terraces have an elevation of about
330 feet and those on Franz Josef Land are up to about 100 feet high,
although marks of terracing were found several hundred feet above this
level. These figures show the scope of the uplift.
Sediments with well-preserved fossils of marine fauna and similar to
those underlying the terraces are found throughout the Piasina-Khatanga
depression which extends across the southern part of the Taimyr Peninsula
from the estuary of the Yenisei to the estuary of the Khatanga River.
Presumably, this depression is an immense graben flanked on the north by
the steep, in places precipitous, cliffs of the Byrranga Plateau and on the
south by cliffs of the mid-Siberian highland which gradually rises southward
and merges with the Putorana “mountains.”
The Byrranga Plateau forms the northern part of Taimyr. It has an
elevation of about 1,500 to 2,000 feet in the highest part. It gradually
slopes northward toward the coast of the Kara Sea, whereas its southern edge
is formed by the fault 1,000 to 1,500 feet high facing the Piasina-Khatanga
depression. The floor of this depression is deeply buried under glacial
drifts overlain by assorted sands, gravel, and clay with fossils of marine
fauna. Hence, it appears that before the uplift the entire depression was
inundated, so that the northern part of Taimyr was an island, and still
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
earlier the entire region had been overrun by immense continental glaciers.
In fact, the Byrranga Plateau, like the mountains of Novaya Zemlya, served
as one of the centers of glaciation.
The marine sediments which cover the submerged continental shelf, as
well as marine terraces and other formerly submerged areas, such as the
Pirasina-Khatanga depression, consist of bedded assorted clays and sands,
the sands being the most common material of the upper strata. Gravelly
and stony sediments are rather uncommon, and usually are found in restricted
areas adjacent to the former or present coasts that are formed by the outcrops
or bedrock, for example, on Kola Peninsula, on the eastern coast of Taimyr,
and in many scattered areas on the arctic islands.
These marine sediments, in turn, or at least their upper beds, are
formed by a thorough reworking by the waves and marine currents of the
glacial deposits left by the previous glaciation of the land before its
subsidence and inundation. Undoubtedly, they include also a large proportion
of alluvial material dumped into the arctic seas by the great rivers such as
Pechora, Ob, Ye
nisei, Khatanga, Lena, Iana, Indigirka, and Kolyma, and
many smaller ones. Near the deltas and along the coast, in general, alluvial
sediments predominate.
In most places the assorted marine and alluvial sediments are underlain
by unmodified morainic deposits showing that the major Pleistocene glaciation
preceded the marine ingression. It is assumed that this ingression took
place during the interglacial period of somewhat warmer climate which,
apparently, caused melting of the ice and a general rise of the sea level.
Thus, it is possible that encroachment of the sea upon the dry land was due
in part to subsidence of the land through epeirogenic processes and in part
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
to the rise of sea level caused by the melt of continental glaciers.
Some evidence of the warmer postglacial, better to say interglacial,
period has been found in the ecological changes of the landscape. Berg
states that “at one time the forests in the tundra extended much farther
north than they do today. Evidence is found in the fact that the peat bogs
of the typical tundra in many places contain stumps and trunks of firs, birches,
and larches sometimes as far as 200 kilometers north of the present northern
edge of the wooded tundra. The period during which the forest extended much
farther north than it does today must have been the dry and relatively warm
postglacial period (the so-called ‘xerothermic’ period).” (Berg, p.16.)
Uplift of the region is still in process. Berg states that at Cape
Cheliuskin on the Taimyr Peninsula are found fairly recent terraces having
elevations of about ten feet and sixteen feet above sea level, which are
covered with driftwood representing the common trees of the contemporary
Siberian taiga. Similar terraces were found on Novaya Zemlya and on the
Novosibirskie Islands. Again, Berg mentions that the Admiralteistva
Peninsula on Novaya Zemlya was an island at the time of Barents and Litke,
i.e., about two hundred years ago, and some other islands become peninsulas,
whereas new islands appeared in places where previously there were none.
Besides the general differential uplift, the land of the Eurasian
Arctic was subject to considerable faulting, at least a part of which
took
presumably took place during the Pleistocens. Saks and Gorbatski state
that “separation of many islands, their present configuration, orientation
of the distribution of the elevated parts on the island — all appear as
being conditioned largely by faulting that took place in Tertiary and
Quaternary time and caused lifting and sinking of various block of the
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
of the earth’s crust.” (Wiese, et al, p. 54.)
There are some indications that the island of Franz Josef Land
represent remnants of an original plateau broken by a complicated system
of radial faults with many grabens depressed below sea level and occupied
by the straits. It is possible that various other groups of arctic islands,
such as Spitsbergen, Severnaya Zemlya, and the Novosilbirskie Islands as
well as Novaya Zemlya, have a similar origin. Quoting Urvantsev, Berg
states that “Severnaya Zemlia attained its present features as a result
of faulting which took place during the Tertiary and Quaternary periods.
Until recently Severnaya Zemlia was connected with Taimyr, from which it
became separated as a result of subsidence, which probably took place
during the postglacial epoch.”
All explorers of the Asiatic Arctic point out a conspicuous difference
in the character of the arctic coast in western and eastern parts of
Siberia. The great rivers of the western part (west of long. 115° E.),
including Pechor, Ob, Taz, Yenisei, and Khatanga and in long but narrow
bays which have all the characteristics of submerged valleys. All these
rivers are building their deltas at the heads of their respective estuaries,
which are hundreds of miles inland from the coast. It has been suggested
that, before the inundation of the lower stretches of their valleys, the
Taz River was a tributary of the Ob, whereas the latter could have had a
common delta with the Yenisei. As contrasted with these, the great rivers
of the eastern sector, including Lena, Iana, Indigirka, and Kolyma, reach
the sea and build enormous typical deltas.
There are various explanations of such a difference in geomorphology
of the coast. It appears that most geologists favor the idea of a secondary
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
and fairly recent subsidence of the western sector of the coast, probably
incident to the most recent reglaciation of the Arctic and chronologically
subsequent to the major uplift which followed the earlier and greater
marine transgression. The uplift of the arctic coast east of the 115th
meridian, apparently, was not interrupted by the secondary subsidence.
Recent Glaciation
The last glaciation of the Arctic, still in progress, has not reached
the degree of the preceding one. As has been stated, this glaciation did
not spread into the mainland, being confined to the arctic islands. The
largest single area covered with the thickest continuous ice sheet is in
Greenland where the glacier reached latitude 60° N. The islands in the
Eurasian sector of the Arctic which are affected by this glaciation include
Spitsbergen, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, the Novosi–
birskie Islands, and a number of smaller islands in various parts of the
arctic seas.
Many students of the Arctic are inclined to believe that this glacia–
tion has already passed its peak, at least as regards the glaciation of
individual islands, such as Novaya Zemlya or Severnaya Zemlya. It is
assumed that the existing glaciers on these and many other Arctic islands
are shrinking and represent the remnants of greater and thicker accumula–
tions of ice. For example, Saks and Gorbatski state that wherever there
are glaciers on the islands of the Soviet Arctic there are marks of the
retreat of the ice (57). As regards Novaya Zemlya, these authors point
out that the present southern boundary of glaciation is in the neighbor–
hood of latitude 72° N. To the south of this line persist only isolated
local remnants such as the Penk glacier. The ice sheet of Novaya Zemlya
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
shrinks quite rapidly. Hence, numerous nunataks are already exposed showing
striation, presence of boulders, and various marks of glacial sculpturing
of the land surface. Glacial formation, including cirques, troughs, and
roches mountonnees
, are particularly conspicuous throughout the middle part
of Novaya Zemlya which now is practically free of continental glaciers. It
should be remembered, however, that not all these marks of glaciation are
necessarily the product of the last and rather weak glaciation. In Pleisto–
cene time Novaya Zemlya was completely overrun by a much stronger glaciation
and a large part of its erosion and sculpturing probably is due to this
earlier glaciation.
Glaciers of arctic islands have the shape of gently domed ice shields.
Some islands still are completely covered with ice. At the peak of glaciation
very likely many other islands were similarly buried under ice. Each island
or group of closely located island had its own “center of glaciation” from
which the ice flowed radially toward the coasts. Reaching the sea the ice
broke away to form icebergs, leaving precipitous ice cliffs all along the
periphery similar to those on Victoria Island. Hence, virtually all rock
waste loosened and triturated by creeping ice was carried into the sea,
with very little of this material left to build up ground moraines on the islands
themselves. Formation of terminal moraines and similar glacial structures
seldom occurred on most islands.
Only after retreat o the ice front from the coasts and considerable
shrinkage of the glaciers did deposition of glacial debris on the islands
become possible. Even now, however, many insular glaciers, like those on
Spitsbergen, Franz Josef Land, Novaya Zemlya, and Severnaya Zemlya, either
reach and coast or send out tongues descending through troughs to the heads
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
of fjords and inlets, they continue to discharge the drifts into the sea,
where they are reassorted by the waves and coastal currents and incorporated
into littoral marine sediments. This caused the general scarcity of glacial
and fluvioglacial sediments on most arctic islands.
Presumably somewhat similar conditions prevailed throughout the arctic
coast of the mainland west of the White Sea, i.e., on the Kola Peninsula and
in the northernmost part of Scandinavia, as well as in other regions in which
the local centers of glaciation were not far from the coast and from which the
ice flowed into the sea.
It appears very likely that the latest glaciation did not extend into the
eastern part of the Eurasian Arctic. Saks and Gorbatski state that at the
present time “the Franz Josef Land is almost entirely covered with ice. On
Novaya Zemlia nearly one-half of the northern island is under the ice, while
on Severnaya Zemlia, which is in higher latitudes than Novaya Zemlia, more
than one-half of the total area of the islands is free of ice. There are no
glaciers on Novaya Sibir’; small glaciers are found only on the islands of
the De Long archipelago. Farther to the east, On Wrangell Island the glaciers
are quite insignificant. Hence, a decrease in intensity of glaciation from
west to east is obvious. Undoubtedly, it depends upon the change in climate,
especially the decrease in the amount of precipitation in the same direction.”
Glacial deposits in the eastern part of the Eurasian Arctic are consider–
ably less common than in the western part; and those which are found locally
are probably the products of earlier Pleistocene glaciations. The relative
age of morainic materials, however, is rather an academic question, because
many details of glacial history of the region, including the boundary of the
latest glaciation, are still unknown.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Surface
of
Formations
Speaking in broad terms, the most common surface formations in the
Eurasian Arctic represent the following four groups:
Marine Sediments
. These sediments, consisting of bedded marine clays
and sands, cover nearly level or gently sloping coastal flats, ranging in
elevation above sea level from a few feet to several tens of feet, and
somewhat higher marine terraces. Much of this land, especially on broad
coastal flats, is boggy, studded with numberless small and usually shallow
lakes, which may occupy in some places more than half of the area.
Morainic and Fluvioglacial Deposits
. These are more common in formerly
glaciated parts of the mainland, especially throughout the arctic coast from
the eastern coast of the White Sea to the estuary of the Yenisei River.
Throughout the wide Piasina-Khatanga depression and morainic material is
largely overlain by marine sediments. Here and there, however, the marine
sediments are absent and boulder morainic clays and clay loams are uncovered.
Scattered throughout the depression are faily well-defined hilly terminal
moraines, some of which probably were high enough to escape submergence
during the marine ingression. In other parts of Eurasian Arctic, including
most of the island, morainic deposits are rather scant.
Except for chains and belts of terminal moraines, most of the land
underlain by the ground moraines is relatively level of undulating. Much
of it is boggy. Lakes are numerous, many of them are in various stages
of being overgrown and replaced by peat bogs.
Rock Land
. Bare or nearly bare rock land from which virtually all loose
material has been stripped by the glaciers, wind, or water, is a common
feature of mountainous regions throughout the Arctic, especially on the
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
northernmost islands. Some smaller arctic islands are nothing more than
bare rocks rising from the sea. On the mainland bare rock land is more
common on high, rugged coasts, such as those in northern Scandinavia, on
the Taimyr Peninsula, especially on its eastern coast, and throughout the
Chukotsk Peninsula. As would be expected, rock land does not occupy large
continuous areas, but occurs locally in combination with various other
surface formations.
Stony Land
. Stony land may be underlain by a rather thin layer of
coarse residual regolith resting on bedrock. In places this layer consists
or rock fragments of various sizes with very little if any finer material.
More commonly, however, fragments of rocks are imbedded in clayey matrix,
especially at some distance below the surface. On the surface in many
places is formed a sheet of broken stones somewhat similar to the desert
pavement or armor so common throughout the deserts in lower latitudes. This
kine of surface formation is typical of flattish mountain tops, plateaus,
and more or less gently sloping and undulating land with bedrock near the
surface. It is more common throughout unglaciated regions in the eastern
part of the Eurasian Arctic, although fairly large areas covered by residual
stony regolith are found in other parts, especially in the mountainous regions.
Soil Characteristics
The soils throughout the greater part of the Eurasian Arctic are affected
by perennial ground frost (permafrost). Freezing fastens the unconsolidated
material, whether residual or sedimentary, to the underlying bedrock. The
grip of the frost is relaxed for a few months, during the short and generally
cool summer, only in a thin layer on the surface. The thickness of such a
layer seldom exceeds a few feet, in
may
many places it is even less than a foot.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Below this layer the ground is frozen to a depth of many feet, in places
more than a thousand feet. This ground may consist of solid rocks, residual
rock debris, or marine, glacial, or alluvial sediments, Deep freezing is
common to all these materials; and as most of them contain enough water
to fill up the void space with ice, and thus solidify the
^
un
^
consolidated
regoliths, virtually all soils of the Eurasian Arctic might be described as
shallow soils overlying solidly frozen rocky substrata, irrespective of the
thickness of various geological formations from which they develop.
In reference to the more specific characted of the arctic soils, the
entire region may be divided into three broad belts — arctic desert, tree–
less arctic tundra, and the subarctic or partly wooded tundra.
Characteristic of the arctic tundra is the scarcity and in places
the virtual absence of vegetation. On bare rock land and stony land in the
arctic desert only a few lichens can survive. On morainic plains and marine
terraces some mosses and a few herbaceous plants, mostly sedges, grow in
patches here and there, usually along the shores of lakes and streams and in
depressions in which some snow might be caught in winter to protect the
plants from frost.
Arctic Desert
. The arcti
d
^
c
^
desert on the mainland is confined to
isolated mountainous areas, chiefly in the eastern part of the Eurasian
Arctic, especially on the Chukotsk Peninsula. Most arctic islands, with
the exception of a few more southern ones, such as Kolguev, the southern
island of Novaya Zemlya, and Vaigach, are in this belt.
The soils throughout this belt are rudimentary. They have not been
examined and described in detail, and no data as to their composition are
available. Our information about them is limited to a few general statements
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
made by various workers of Soviet polar stations who attempted to grow
some vegetables. At the end of 1947 more than 80 stations were maintained
along the Northern Sea Route. Some of them are on the coast of the mainland,
predominantly at the mouths of the larger rivers such as Pechora, Ob, Yenisei,
Khatanga, Lena, Indigirka, and Kolyma; others are built on bleak arctic
islands such as Novaya Zemlya, Belyi, Uedinenia, Russkii, Bolshoi, and
Kotelnyi. The personnel of these stations ranges from three to several scores
of people. At various stations attempts are
bie
being made to maintain green–
houses and hotbeds in order to provide the personnel with some fresh vegetables.
Following are a few extracts from reports on the early experience of these
people.
The polar station at Russkaia Gavan, on the west coast of the northern
island of Novaya Zemlya, reported: “We attempted to do a little farming and
decided to grow some onions and potatoes. The main difficulty was in the
lack of good soil. We searched the area around the station having a radius
of about five kolometers and, with great difficulty, collected by handfuls a
small amount of dirt, mixed it with dungs, filled up a box and planted
[:
]
six bulbs of onions. Rays of northern sun and great care of “the plantation’
rewarded us for our labor: green onions grew tall and juicy. We did not wait
too long and had a feast….” (Sov. Arktika, 1940, 5:80.)
Somewhat similar reports came from the station at Providence on the
Chuktosk Peninsula. There several greenhouses were under construction. The
workers reported that the soil at Providenie is hardly more than 1 1/2 to 2
inches thick, and even this is mixed with rubble and other coarse debris. It
was necessary to scratch the ground and screen the dirt. Two men, working
from nine to ten hours a day, in four and a half days were able to collect
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
only a little more than four cubic yards of poor dirt which had to be mixed
with lime, mineral fertilizers, and manure to be of any use. Somewhat later
they found along the banks of a stream small eight- to ten-inch accumulations
of sand, silt, and clay and moved it to their farm. Several cubic yards of
this “soil” were shipped to the station on Wrangel Island where other green–
houses were built.
One of the largest polar stations at Tiksi near the mouth of Lena River
also had to ship the soil for its greenhouses from Yukutsk, which is nearly
a thousand miles to the south. These simple reports give a fairly clear idea
of the general character and condition of the soils in the polar belt of the
Eurasian Arctic.
Tundra and Wooded Tundra.
The economic value of soils of the arctic
tundra and the wooded tundra, which represent the second and third physiographic
belts respectively, is not much higher than that of the soils of arctic desert.
The tundra woils, however, are somewhat better developed and more diversified.
No systematic survey of the soils of any part of the tundra has been made, and
our information about these soils is very scanty and superficial. Descriptions
of the tundra soils in various reports are limited to a few broad general
statements, and even these statements are largely theoretical; therefore,
little can be said about soil conditions in individual regions of the Arctic.
Eurasian Arctic Islands
Franz Josef Land is a group of several faily large islands and probably
not less than a hundred small ones. The combined area of all islands is about
7,000 square miles. About 90% of this area is covered by thick ice, leaving
only a few hundred square miles of bare land. Most of this land is in narrow
strips stretching along the shores of the larger islands, and only a small
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
part of it is formed by nunataks protruding here and there through the ice
sheet. The thickness of ice in some places is more than 500 feet. Some
smaller islands are completely covered with ice and in the inner parts of
the archipelago the ice covers groups of islands as well as the narrow
straits between them.
Some coasts of islands are fairly high and in places precipitous, being
formed by outcrops of basalts or various sedimentary rocks. In other places
the coasts are low, forming the edges of fairly wide coastal lowlands or
young marine terraces. Dissection of land by running water is quite insig–
nificant. The area that is not occupied by the glacier is much too small
for the development of concentrated streams. Most of the short “ravines” cut
on high coasts were excavated largely by the glaciers descending from the
plateau to the sea. Some of these glacial troughs were cut below sea level
and now are occupied by narrow bays. In general, however, the shores of
most islands are little dissected and typical fiords are absent.
Wherever the bedrock is not covered with ice a thin mantle of regolith
is being formed, especially by the frost splitting and wind corrosion of rocks
exposed to the polar climate. Steeply sloping outcrops of bedrock are
stripped even of this mantle. The loose and generally coarse material is
carried to the base of cliffs and accumulates on the gentler slopes, in short
U-shaped ravines and other depressions.
The lowlands along the coasts and terraces are built largely of sandy
marine sediments. The unmodified glacial and fluvioglacial deposits are
less common, although here and there these materials are interbedded with
marine clays and sand, and in a few places form patches over the bedrock.
Firtually all soils on the archipelago are frozen, and thaw during summer
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
only to a depth of a foot or a foot and a half.
Vegetation is very scant; on rocky coasts there are only a few lichens.
In some ravines, however, a few species of flowering plants such as arctic
poppy and buttercup, some sedges, and occasionally low clumps of dwarf polar
willow may survive. Scattered patches of low coastal flats are occupied by
predominantly bare polygonal tundra. Small lakes and ponds, mostly oval,
are numerous.
Kolguev Island
has an area of about 1,440 square miles and is separated
from the mainland by a strait about 45 miles wide. The island is practically
surrounded by shallow waters and wide sand bars. In a few places, mostly on
the southern and southeastern coasts, there are some gravelly beaches. Its
shores, however, are undercut by waves and are faily high and precipitous,
especially on the east coast where the cliffs are up to 100 and in places
150 feet high.
In general, Kolguev is a rather low island built entirely of loose
unasserted glacial drift and marine sediments. No bedrock is exposed anywhere
on the island or its banks. Marine and glacial deposits are predominantly
sandy. Morainic boulder clays and clay loams are less common.
The highest part of the island, marking up about two-thirds of the entire
area, stretches through the middle part from southwest to northeast. It has
an elevation of about 200
to
or 300 feet and is formed by groups of low,
presumably morainic hills that are arranged in three roughly parallel chains.
The hills range in relative elevation above the surrounding plain from less
than 100 to about 200 feet. Most of them are built of laminated, and in places
boulder, morainic sands. Less common are hills built or boulder clays. The
highest point on the island is Savande’s Hill in the northeastern part.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
It has an absolute elevation of about 550 feet.
The main streams, of which the largest is the Peschanka (Sandy) River,
run between these morainic ridges in rather narrow but fairly deep valleys.
North and south of the elevated middle part of Kolguev are nearly level
areas of coastal lowland ranging in elevation above sea level from about
10 feet to about 30 or 40 feet. The lowland on the southern coast is in
places more than 12 miles wide and slopes toward the sea so gently that it
appears most perfectly flat. The lowland on the northern coast is somewhat
less extensive. Both these lowlands, locally called
lapta
, are formed by
geologically very young marine terraces and are built largely of sandy marine
sediments. They are studded with a great many small and shallow lakes in
every imaginable stage of overgrowth with mosses and sedges.
Some of the lakes are glacial, others are remnants of old marine lagoons,
and still others are formed by flooding of local depressions with melt water,
the drainage of which is made impossible by solid freezing of the subsoil.
The largest lake is Peschanoe (Sandy Lake) in the eastern part of the island.
The entire island is occupied by mossy tundra. Both coastal flats are
boggy; many former lakes are replaced by peat bogs. Rather sandy bog soil with
a thin layer of fibrous peat underlain with bluish-gray subsoil is the most
common type on both coasts. Some tide marshes, low deltas, and old filled-up
lagoons are occupied, at least in part, by peculiar arctic
solonchak
(salind soil).
The soils in the middle and higher part of the island are better drained
and generally somewhat better oxidized. Some of these soils on morainic sandy
hills were referred to as very weakly podsolic soils.
Novaya Zemlya
consists of two large islands, Severnyi and Iuzhnyi
(Northern and Southern), which are separated from one another by
^
^
the narrow
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
63-mile-long Matochkin Shar (strait), and several smaller islands. The
largest among these smaller islands is Mezhcusharskii Island having an
area of about 300 square miles and located near the western coast of the
southern island.
The northern and southern islands form a broad arch separating the
Barents Sea from the Kara Sea. Its length is nearly 600 miles and it
ranges in width from about 40 miles to about 70 miles. The combined area
of Novaya Zemlya is approximately 35,000 square miles,
The combined area
of Novaya Zemlya
of which about 20,000 square miles represent the area of
the northern island.
Nearly one-fourth of this area is covered with a thick ice sheet which
occupies a large part, probably half, of the northern island. The average
thickness of ice is several hundreds of feet and the maximum thickness is
more than 1,000 feet. South of latitude 74° N. there are only small local
glaciers — rapidly shrinking remnants of formerly more extensive glaciation.
Novaya Zemlya is a mountainous country. The southernmost part of it is
the lowest. The greater part of the southern island, up to about the latitude
of Bezimennaia Bay, is merely a hilly plain; in the extreme south, the
relief is more or less featureless. A large part of the country is occupied
by numerous small lakes and bogs. The average elevation is in the neighbor–
hood of 200 or 300 feet. Elevation gradually increases northward so that in
the middle part of the island at about latitude 72° N. it exceeds 1,000 feet
and locally is even more than 1,500 feet. From this middle part the country
slopes rather gently eastward and westward, both slopes being fairly well
dissected by erosional valleys.
On both sides of Matochkin Shar, mountains reach an elevation of about
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
2,000 ot 3,000 feet and the relief acquires alpine character owing to
dissection of the original massif by numerous deep valleys. The greater
part of the northern island is occupied by mountains, of which most promi–
nent is Lomosov Range on the northern coast, with a maximum elevation of
about 3,500 feet (Blednaia Mountain in the neighborhood of Mae’s Bay).
On the extreme north of Navaya Zemlya the country slopes toward the sea
in a series of well-defined marine terraces characterized by a conspicuous
absence of any marks or traces of glaciation.
The coasts of Novaya Zemlya are severely dissected by erosion. Deep
fjords, some of which are more than 15 or 20 miles long, are numerous and
increase the length of the shore line to almost 3,000 miles. Steep, rocky
cliffs rising from the sea, however, are not a typical feature of Novaya
Zemlya. According to Gorbatski and Saks, the shores of Novaya Zemlya
usually are flanked by stretches of coastal flats which in places are several
miles wide and range in elevation from 30 to more than 50 feet. These flats
obviously represent the most recent marine terraces.
The northern island of Novaya Zemlya is entirely in the belt of arctic
desert. Most of its middle part is covered with ice. Only narrow stretches
of rocky land along the coast and occasional nunataks are free of ice, although
numerous valley glaciers radiate from the central ice sheet and descend to
the heads of fjords and bays to form small icebergs. In one place on the
Kara Sea coast, however, the ice sheet reaches the shore and forms a continuous
sheet of ice (the Nordenskiöld glacier) about 60 miles long.
A large part of the land that is not occupied by glaciers consists of
bare outcrops of bedrock, including Cambrian, Silurian, and Devonian formations.
Probably the most common rocks are represented by the lower Silurian limestones,
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
sandstones, and conglomerates. Local accumulations of coarse morainic
materials, especially in valleys, are not uncommon. Here and there are
scattered small terminal and border moraines. The coastal flats are
built of marine sediments and occupied by the polygonal tundra.
The southern part of Novaya Zemlya including most of the southern
island, is in the arctic tundra belt. Mossy tundra is the most conspicuous
feature of the landscape. Only in the extreme south are there areas overgrown
by shrubs. Outcrops of bedrock are common, especially along the coasts,
although most of the hilly plains and coastal lowland and underlain by
morainic (largely clayey) materials and marine sediments. The dominant
soil is of a poorly oxidized peaty tundra type. Peat cover usually is rather
thin, ranging in thickness form a few to about 10 inches, and is underlain
by gray or bluish-gray materials, in places mottled with rusty stains.
Some local soils developing on the better-drained slopes of hills, especially
those soils from sandy materials, have been classified as very weakly pod–
solized soils. Such a classification, however, is rather doubtful. Generally,
few soils thaw to a depth greater than 2 feet during summer. In most places
maximum thickness of the defrosted topsoil ranges between 10 and 20 inches.
Vaigach Island
is located between the southern tip of Novaya Zemlya
and the mainland. It is about 65 or 70 miles long and some 30 miles wide;
its area is 1,300 square miles. It is separated from Novaya Zemlya by the
wide strait Karskie Vorota, and from the mainland by the much narrower
Yugorskii Shar. The surface of Vaigach is more or less level, the highest
point on the island has an elevation of about 300 feet. The entire area
is occupied by typical mossy and rather boggy tundra with numerous small
lakes and peat bogs. The soils are predominantly clayey.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Severnaya Zemlya
archipelago includes four fairly large islands —
Komsomolets, Pioneer, October Revolution, and Bolshevik — as well as
many small ones. The combined area of all these islands is about 14,000
square miles. Roughly about 40% of this area is occupied by glaciers having
a thickness up to several hundred of feet. Information about these islands
is meager. It appears that a fairly large part of the whole area is occupied
by low mountains, the highest of which probably have an elevation of a little
over 2,000 feet. The northern part of Komsomolets Island is a fairly level
lowland. Presumably the western part of October Revolution Island and the
northern part of Bolshevik Island have similar character. Hence, the coasts
of the islands are partly high and steep and partl
l
^
y
^
low, consisting of broad,
gently sloping marine terraces with edge undercut by waves.
Forms of relief
trh
throughout Severnaya Zemlya appear to be somewhat
smoothed by movements of ice, and later by the glacial melt water. A large
part, probably by far the greater part, of these islands is covered with a
fairly thick mantle of morainic material and fluvioglacial deposits, and the
remaining part by assorted marine sediments. Glacial deposits consists largely
of boulder clays and clay loams. Outcrops of bedrock are perhaps not uncommon
on high coasts and in mountainous areas, but the total area of rock land and
stony land appears to be very small. Marine sediments underlying the coastal
lowland consist predominantly of sands and loamy sands.
The entire archipelago is in the belt of arctic desert. Vegetation is
very scant and a large part of the land is virtually bare. Most of the coastal
lowlands and undulating plains farther
inaldn
inland are occupied by typical
polygonal tundra. Here vegetation is somewhat richer than throughout the
inner parts of the islands, although it still consists predominantly of mosses
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
and lichens with very few flowering plants, and is confined almost entirely
to patches and “garlands” surrounding the bare polygons.
Novosibirskie Islands
include five fairly large islands — Kotelnyi,
Faddeievskii, Novaya Sibir, Bolshoi, Liakhovskii, and Malyi Liakhovskii —
and several smaller ones. The combined area of the entire group is about
14,000 square miles. The islands are separated from the mainland by the wide
Dmitrii Lapev Strait. Between Kotelnyi and Faddeivskii islands is an
expansive sandbank which generally is dry but is subject of flooding when
water rises above the ordinary level. This is the area locally called
Ulakhan-Kumakh, butbetter known as Bunge Land. When it is dry, Kotelnyii
and Faddeievskii become one island with a very low and sandy middle part.
All islands of this group are low and have a rather featureless relief.
The highest point on Kotelnyi Island has an elevation of about 750 feet.
Elevation of the highest points on Faddeievskii and Novaya Sibir is only
about 250 and 260 feet, and that on Malyi Liakhovskii is probably less
than 200 feet.
By far the greater part of the area of these islands is covered by
Pleistocene and post-Pleistocene marine, lacustrine, and deluvial sediments.
It appears that typical morainic materials are absent. A peculiar feature
of this region is a widespread occurrence of fossil ice under a thin
mantle of recent sediments. It has been reported that in some places
the thickness of fossil ice is great than 200 feet. It is assumed that
this ice could have been formed during the glacial ages by accumulation in
valleys and depressions of neve which subsequently was covered by layers
of deluvium and thus protected against melting.
The outcrops of bedrock are rather few. They occur in widely spaced
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
“mountainous” areas which presumably represent the remnants of strongly
eroded old horsts. On Bolshoi Liakhovskii Island there are two roughly
parallel ridges stretching along the northern and southern coasts. It is
believed that these ridges are remnants of two horsts. Between them is a
wide graben in which the deposits of fossil ice and particularly conspicuous.
Throughout this general depression or graben there are numerous closed local
depressions or hollows separated from one another by massive barriers built
of fossil ice. The difference in elevation between the divide and the
bottom of the depression may be more than 50 or 60 feet. The eathy mantle
over the ice on the divides is rather thin, whereas accumulations of mud in
depressions may attain considerable thickness. It is assumed that these
depressions are formed by uneven melting of fossil ice and are gradually
filled up with mud washed into them from the surrounding divides. Thus,
thickness of sediments above the ice becomes very uneven and if the ice melts
completely, then on the site of former dperessions appear fairly high mounds
or
baidzharakh
. These various thermocarst formation are very common
throughout the Novosibirskii Archipelago.
The entire archipelago is in the belt of arctic desert, and its vege–
tation is very scant. Typical poorly drained, polygonal tundra is the most
conspicuous feature of the landscape; the low parts of the northernmost
island are especially poorly drained and boggy. The greater part of Faddeievskii
and nearly all of Novaya Sibir are covered by marine sediments. Hence, it
appears likely that the ground on these islands is somewhat more sandy than
on other islands. Wherever bedrock outcrops the land is covered by coarse,
stony regoliths. Such, probably, is the case on the southern coast of
Bolshoi Liakhovskii Island.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Wrangel Island
is about 90 miles long from east to west and some 40 miles
wide. It has an area of about 3,000 square miles. The middle part of the
island, extending along its long axis, is occupied by the range formed by
more or less smoothly rounded mountains. The highest is Sovetskaya Mountain,
having an elevation of about 3,600 feet. Several other mountains range in
elevation from about 2,000 feet to about 2,500 feet. On the northern and
southern coasts are fairly wide stretches of level lowland bordered by
numerous sandbanks and bars and shallow lagoons. The space between the
coastal lowlands and the middle mountains range is occupied by low, gently
rounded hills ranging in elevation from a few hundred feet to about 1,500
feet. The southern belt of these hills probably represents remnants of a
moderately dissected plateau. The western and especially the eastern shores
of the island are high and rather steep.
The northern lowland is occupied by the sol-called Tundra of the Academy
of Sciences. It elevation at the contact with the foothills of the moun–
tainous belt is about 150 feet and from there is slopes very gently toward
the sea. The entire flat is occupied by polygonal tundra with numerous small
lakes and streams. The ground is predominantly gravelly clay. Vegetation
consists largely of mosses and lichens along streams between the adjacent
bare polygons. In the eastern part of this tundra up to 70% of the surface
is bare. The maximum thawing in summer extends to a depth of about 15 to 20
inches on bare spots, and probably not more than half of this under moss.
Most of the southern lowland is occupied also by stony polygonal tundra.
Here, however, there are some areas overgrown with lichens, leaving practically
no bare spots. Similar lichen tundras are common throughout the middle part
of the island, especially on gentle southern slopes of mountains. Soils on
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
these slopes are affected by solifluction which is in places strong enough
to produce a peculiar terracing of the sloping land.
Vegetation is somewhat richer in the valleys on alluvial deposits.
Here and there in these valleys are scattered small areas overgrown with
drawf polar willow.
Smaller Islands of the East Siberian Sea
. This group includes about
a dozen small islands each having an area of a few square miles. Five of
these islands, Jeannette, Henrietta, Bennett, Zhokhova, and Vilkitskii, form
the De Long Islands. Another group of six islands in the region of the mouth
of Kolyma River are called Medvezhii or Bear Islands. The easternmost of
these small islands is Herald Island located some 50 miles east of Wrangel
Island.
All these islands are rocky, formed by blocks of hard rocks (granite or
basalt), rising from the sea. Their banks are predominantly high and in
many places precipitous. On some islands, however, small sandy and gravelly
low areas are attached to the high rocky cliffs.
Herald Island is about 5 miles long and a mile or a mile and a half wide.
It is formed by a block of granitic rock rising about 300 to 400 feet above
sea level. Its banks are steep, mostly precipitous, and the surface consists
of relatively level areas and a few rocky hills having an absolute elevation
of some 800 to 1,000 feet. Most of the surface is covered with loose
[:
]
fragments of broken rocks. Here and there are patches of mossy or lichen
tundra on stony substratum.
Medvezhii (Bear) Islands, like Herald Island, and formed by granitic
rocks rising from the sea. The best-explored of these islands is Chetyrekh–
stolbovoi Island which is about 6 miles long and hardly more than a mile and
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
a half wide. The highest point on this island has an elevation of about
300 feet. Actually it is formed by two islands connected by a narrow, low
sand bar. The surface of the island is covered by fragments of rock with
hardly any finer material. Some banks are high and steep, others are low.
In some places low, sandy areas are adjacent to rocky cliffs; here are
patches of boggy polygonal tundra. Others islands of this group have similar
character.
De Long Islands are formed largely by blocks of basaltic rocks. Their
rocky banks are high and in many places precipitous. Some cliffs on Bennett
Island are nearly 1,000 feet high. The surface usually is covered by broken
rocks. A certain part of Bennett Island and almost the whole of Henrietta
Island, the latter having an area of some 5 square miles, are occupied by
glaciers — probably the only large glaciers found in the eastern part of
the Eurasian Arctic. Here and there along the shores of these islands are
narrow gravelly or sandy beaches and occasional small areas of coastal low–
land occupied by polygonal tundra.
Islands of the Kara Sea.
Throughout the Kara Sea are scattered many small,
low islands which presumably were formed by a relatively recent uplift of the
sea bottom. With a few exceptions they are built of marine sediment, are
rather flat, and have steep shores undercut by waves. They include Vize
Island, some 12 or 15 miles long, Uedinenia having an area of about 16 square
miles, somewhat larger Belyi Island having an elevation of some 30 or 40 feet,
several other equally low islands near the coast of the mainland, a group of
Kirov Islands, another group of Islands of Arctic Institute, and others.
Practically all these islands are occupied by monotonous polygonal tundra.
The northernmost of them is Ushakov Island, almost entirely covered with ice.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Mainland of the Eurasian Arctic
The main part of the continental division of the Eurasian Arctic is
formed by an immense coastal lowland which extends from the eastern shores
of the White Sea to the delta of the Khatanga River. The width of this
belt is greatest in the northwestern Corner of Siberia, i.e., between the
northern Ural Range and the Yenisei River, and decreases with distance east–
ward and westward.
The widest part of this belt is divided by the estuaries of the great
Siberian rivers into a series of peninsulas — Iamal, Taz, Gydan, and Taimyr.
The Iamal Peninsula, which is wholly in the arctic belt, is about 600 miles
in length along its meridional axis. East of the estuary of the Khatanga
River the continental arctic belt narrows so that in the region of the delta
of the Kolyma River its width is only a few tens of miles. (The name of a
settlement near the mouth of Kolyma is Krai Lesov which means “the border
of forests,” a boundary between the taiga and tundra.)
Throughout this belt of lowland are scattered isolated massifs or blocks
of higher land. The largest of these blocks are the Byrranga Plateau, which
occupies the northern part of Taimyr, and the Pai-Khoi Range which forms the
northernmost extension of the Urals. Considerably smaller and lower are the
Pronchischev Range between the mouths of the Anabar and Olenek rivers, and the
Chekanovski Range west of the delta of the Lean. Elevations of highest points
in the former are of the order of 500 or 600 feet and those of the latter
1,000 to about 1,500 feet.
East of the Kolyma the coastal belt is occupied by the northern slopes of
the Aniui, Anadyr, and Chukotsk Mountains. The Anadyr range is the highest.
The westernmost part of the Eurasian Arctic coast also is predominantly
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
mountainous. The northern part of the Kanin Peninsula is occupied by
the Kanin-Kaman Range with elevations up to 500 or 600 feet. The Murman
Coast on the Kola Peninsula is a dissected plateau having an elevation of
about 400 to 600 feet and dropping rather sharply to the sea. Elevation
of the coastal mountains increases westward to more than 2,000 feet in
the northernmost part of Scandinavia.
Mountains at both ends of the Eurasian arctic coast are built of hard
rocks. Their summits and steeper slopes are virtually bare. Flattened tops,
gentler slopes, and other similar areas are largely covered with coarse frag–
ments of broken rocks. Only in ravines, valleys, and local depressions are
found deposits of more thoroughly comminuted and weathered materials, in–
cluding glacial drifts and fluvioglacial or alluvial sediments. Most of
these materials are stony or gravelly. Hence, a large part of these regions,
if not the greater part, is virtually devoid of any soils in the true sense
of this word. Tundra soils throughout the arctic mountains are confined
predominantly to the valleys and depressions. Parent materials of these
soils may be mechanically assorted or heterogeneous. Their earthy part
ranges in texture from almost pure gravel or coarse sand to clay. Practically
all these soils develop under condition of impeded internal drainage, and
therefore are very weakly or not all oxidized.
The coastal lowland is usually divided, according to its soil and
floristic characteristics, into three belts: arctic tundra, which represents
the southernmost part of the arctic desert; tundra proper, or “typical”
tundra, including mossy, grassy, and shrubby tundras, and the wooded tundras.
These floristic land types are not confined to the lowland; essentially the
same mossy, shrubby, or wooded tundras occupy the valleys, foothills, and
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
gentler slopes of the mountains throughout the arctic belt. The distribu–
tion of these various types of tundra in the mountainous regions is very
patchy rather than continuous as on the lowland.
Nearest to the coast is the flattest and the lowest belt of arctic
tundra. It varies in width from a few miles to several scores of miles.
In some places it is almost perfectly level but usually it slopes gently
toward the sea. Almost everywhere it is studded with innumerable small
and usually shallow lakes which may or may not be interconnected by sluggish
channels. In places lakes occupy probably more than half of the area and
it appears that water fills to the rim every available depression having
no outlet.
By far the greater part of this belt is underlain by marine sediments.
Marine sands and sandy materials predominate in the western division of
the arctic coast, especially between the mouths of the Pechora and Yenisei
rivers. East of the Yenisei, especially between the Khatanga estuary and
the delta of the Lena River marine clays are probably more common than sands.
Unmodified and unassorted morainic materials are relatively less common
throughout this belt, and occur locally in the relatively higher parts which
are removed from the coast. River terraces and deltas, especially the immense
delta of the Lena, are built of finer silty and clayey alluvial sediments.
Numerous low islands which form the Lena Delta are covered with fairly thick
layers of peat. Most of this area, however, is overgrown with mosses and
lichens, and contains numerous flat boggy and grassy depressions and shallow
lakes. Throughout other parts of the belt peat is uncommon. Polygonal tundra
represents the most conspicuous feature of the landscape throughout the entire
belt.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
According to Suslov, “Arctic tundra is characterized by a considerable
weakening of the soil forming process, absence of shrubby and sphagnum-moss
bogs, and widespread occurrence of polygonal tundra. Soil formation in the
Arctic is characterized by the predominance of physical weathering, weakness
of biochemical processes, slow leaching of simple salts from the soil, sub–
dued microbial activity, insignificant accumulation of peat and raw humus,
development of peculiar tundra gleisoils, (and) absence of morphologically
developed podzolic soils even on sandy materials. The rigor of winter winds
is greatly enhanced in Arctic tundra, whereas the thickness of snow decreases.
Therefore, strong breaking of the surface soil into polygons and formation of
bare areas between the cracks take place. In this way polygonal or Arctic
spotty tundras are formed on clayey or peaty-glei substrata.” (Suslov, S. P.,
Physical Geography of the USSR
. 1947. Page 36.)
The second belt is formed by the tundra proper or “typical” tundra.
This, probably, is the widest of the three major subdivisions of the Eurasian
Arctic. East of the Lena River most of this belt is underlain by morainic
materials, among which gravelly and bouldery clays and clay loams are quite
prominent. Assorted marine sediments cover a considerable part of the area,
especially throughout the wise Piasina-Khatanga depression.
Most of this area is characterized by gently undulating or gently rolling
relief with scattered low ridges of terminal moraines. Lakes are numerous,
although, in most places, probably less so than in the belt of littoral
arctic tundra. Peat bogs are faily common, although layers of peat are
usually rather thin. Soils are predominantly boggy, unoxidized, and strongly
affected by solifluction and other similar processes. It has been reported
that the soils on the better-drained slopes of sandy hills and ridges might
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
be very weakly podsolized, although such development appears to be rather
doubtful.
Several forms of “typical” tundra, such as mossy, spotted, lichen, grassy,
and shrubby, are differentiated on the basis of dominant vegetation. Mossy
tundra develops especially on poorly oxidized clayey soils strongly affected
by gley formation. Spotty or mound tundras are formed largely on sloping
land which is occupied predominantly by clayey soils and is subject to strong
solifluction. Lichen tundra charactizes relatively better drained and more
sandy soils.
The wooded tundra, which represents the third belt, is formed by tracts
of open tundra (especially mossy and shrubby) intermingled with areas occupied
by thin forest or stunted solitary trees scattered among the tundra shrubs.
Most of this belt is underlain with morainic materials and characterized by
gently undulating to rolling topography. Lakes are few in this belt but peat
bogs are numerous and extensive.
Bog soils are still the most common throughout this region, although the
area occupied by weakly podsolized soils and, especially, by poorly drained
podsolic soils (gley-podsolic and peaty-podsolic soils) are not uncommon and
become larger and more numerous with transition to the taiga. These soils
develop in wooded tundra not only on sandy parent materials but also on
clayey ones, such as morainic boulder clays and clay loams.
Polygonal tundras do not form in the wooded tundra belt, and spotty and
mound tundras are less common than in the treeless typical tundras.
No data as to the pattern of distribution of various soils in different
parts of the tundra belt of Eurasia are available. Therefore, only a few very
general statements can be made about some relatively better known regions.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
Bolshezemelskaia Tundra
. The greater part of this region is underlain
by morainic materials. Here and there are scattered groups and chains of
low hills representing terminal moraines. Along the coast stretches a
boggy lowland covered with clayey marine sediments and occupied largely by
polygonal tundra. Farther inaldd
^
inland
^
, boggy gley soils are most common. Usually
they are covered with an inch or two or peaty material below which is a typical
bluish gley. The thickness of peaty cover increases southward.
The ground thaws during summer to a maximum depth ranging from about a
foot in peat bogs to about 5 or 6 feet in better drained sandy areas. Clayey
soils thaw to a depth of about 3 or 4 feet (Liverovskii). The thickness of
the perennially frozen layer increase from west to east. According to
Grigoriev, this layer in the region of lower Pechora is about 60 feet thick;
in the region of Vorkuta it varies from about 250 feet to more than 400 feet,
and farther to the east, on Vaigach, its thickness is well over 1,000 feet.
Iamal Peninsula
. Iamal Peninsula is more than 600 miles long on its
meridional axis and about 120 miles wide. It is a low country. Except for
the southernmost part of the peninsula, the elevation of its inconspicuous
watershed, which is nearer the eastern coast, probably nowhere exceeds 100
feet. In the middle of the southernmost part, the elevation of the land
increases to about 200 or 300 feet. At the northern tip of Iamal lies
fairly large, equally low and flat Belyi Island which is separated from
the mainland by narrow Malygin Strait.
It appears that the greater part of Iamal and the entire Belyi Island
have emerged from the sea quite recently. All this area is underlain by
sandy marine sediment.
The entire peninsula may be divided into three parts: the northernmost
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
part extending from Malygin Strait to the latitude of the Nei-to and
Jambu-to lakes; a middle part extending farther south to about the latitude
of the Iarro-to lakes; and the southern part stretching south of Iarro-to
lakes. The northern part is the lowest and flattest. It slopes very gently
to the north and northwest and is occupied largely by polygonal and lichen
tundras. Lakes are less numerous than in other parts of the peninsula.
Some areas are overgrown with moss but peat bogs are practically absent.
The middle part is somewhat higher than the northern part. It is
occupied predominantly by mossy and boggy tundra on sandy materials. In
contrast to the northern part, a large number of lakes of various sizes are
scattered throughout this part of Imal. The largest of these are the Nei-to,
Jambu-to, and Iaaro-to lakes, each of them having an area of some 80 to 100
square miles. Many lakes are overgrown with moss and sedges. Here and there
are patches overgrown with arctic shrubs, drawf willow, and birch. Relatively
elevated and drier areas are occupied by
^
^
lichens.
The southernmost part of Iamal is in the belt of wooded tundra. Trees,
however, are small the thinly scattered. Stunted birch and shrubs of alder
predominate. In some places some stunted conifers grow. Small lakes and
peat bogs are numerous. The highest middle portion of this part of Iamal
probably was not submerged at the time of the marine ingression. It is covered
by morainic material with boulders. Here and there are scattered low, gently
sloping hills rising some 50 or 60 feet above the surrounding plain and
probably representing terminal moraines.
Gydan Peninsula
. Gydan Peninsula is formed by expansive flat lowland
between the estuaries of the Ob and Yenisei rivers. The southwestern part
of it, separated from other parts by the Taz River and its estuary, is referred
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
to as the Taz Peninsula. The wide coastal belt and a large northern part
of Gydan and covered mostly by sandy marine sediments. Considerable areas
in a relatively higher inner part of the peninsula are underlain by gravelly
and, in places, bould
r
^
er
^
y glacial drifts. Here and there are scattered low,
presumably morainic hills rising to about 50 feet above the surrounding
country. Sandy areas throughout this region alternate with areas that are
covered with somewhat stratified loams, gravelly loams, and heavier materials.
Lakes are numerous throughout the peninsula.
Along the coast and throughout the northern part of Gydan, polygonal and
“spotty” lichen tundras are the dominant characteristic of the landscape.
The middle part of the peninsula is occupied predominantly by moss tundra
with considerable areas overgrown with polar birch, willow, and other arctic
shrubs, whereas the southern part is in the wooded tundra belt. Sparse,
stunted larch and pine are the most common trees. Most of the area is
rather boggy.
The area between the lower Ob River and the Taz River is referred to as
Bolshaia Nizovaia Tundra. The northern part of this extensive region is an
open mossy and scrubby tundra, whereas the southern part is occupied by
wooded tundra.
Taimyr Peninsula
. Taimyr Peninsula consists of two different parts;
(
1
) northern, which is occupied by the Byrranga Plateau (questa); and (
2
)
southern, occupied by the Piasina-Khatanga depression. The Byrranga Plateau
extends from the Piasina River to the east-northeast. The lower Taimyra
(Nizhniaia Taimyra) River cuts it in two parts — western and eastern.
The western part is lower and less dissected than the eastern part. It
slopes very gently northward and it fairly wide coastal part is covered
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
part is covered with marine sediments which extend to about the 300-foot
contour. The eastern part of Byrranga is dissected into a series of ridges
which extend to the rocky coast of the Laptev Sea.
In Pleistocene time the entire plateau was glaciated and marks of
glaciation are in evidence throughout the region. The Byrranga, however,
served as a local center of glaciation and little of morainic material
has been left in the region. The soils in this part of Taimyr are very
stony and rather shallow with numerous outcrops of bare rocks.
The Piasina-Khatanga depression has been loaded with glacial drifts
and inundated during the postglacial marine ingression which left a large
part of this region covered with marine sediments. The greater part of
this extensive lowland is occupied by boggy soils of mossy and lichen
tundras.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
BIBLIOGRAPHY
1. Berg, L. S.
Priroda
(in Russian). English translation:
Natural
Regions of the USSR
, 436 pages. The Macmillan Co. New York,
1937.
2. Bunge von,, A. “Naturhistorische Beobachtungen und Fahrten im Lena
Delta” (in German). Academy of Science
Bull
., vol.29, p.422-75.
3. Gerasimov, I. P., and Markov, K.K.
Glacial Period in the territory of
the USSR
(in Russian with English summary), 462 pages.
Acad. Sci. USSR. Moscow - Leningrad, 1939.
4. Gorodkov, B. N. “On specific properties of Tundra soils” (in Russian).
State Geographical Society.
Izvestia
, vol. 71, no.10, 1939.
5. Grigoriev, A. A. “Soils of subarctic Tundras and wooded Tundras of
Eurasia” (in Russian) Pochvovedenie, vol. XX, no.4, Leningrad,
1925.
6. ----.
Subarctic
(in Russian), 171 pages. Acad. Sci. USSR. Moscow–
Peningrad, 1946.
7. Evgenov, N. I.
Pilot of Wrangell and Herald Islands
(in Russian),
77 pages. Glavsevmorput. Leningrad, 1937.
8. Ivanov, I. M. “On soil formation in the Arctic” (in Russian).
Bull
.
Institute for survey of the North. No.49, Gostekhizdat.
Moscow - Leningrad, 1931.
9. Leffingwell, E. deK. “The Canning River Region Northern Alaska.”
251 pages. ill. U.S. Geological Survey
Prof.Paper
109.
Gov. Printing Office, Washington, D.C., 1919.
10. Livorovski, Yu. A. “Soils of the Tundras of Northern Regions”
(in Russian).
Reports
of Polar Expedition of the Acad. Sci. USSR.
vol. 19. Leningrad, 1934.
11. ----. “Soils of the Far North and some aspects of their chemistry”
(in Russian).
Chemization of Socialist Agriculture
, No.3, 1937.
12. ----.
Soils of the Boggy Tundra Belt
(in Russian), 54 pages. Acad.
Sci. USSR. Moscow - Leningrad, 1937.
13. Lukashev, K. I. “Mound formation as a manifestation of the tension
in the perennially frozen soils” (in Russian).
Annals
.
University of Leningrad, vol. 3, pp. 147-58. Leningrad, 1936.
EA-PS. Nikiforoff: Soils of the Eurasian Arctic
14. Nikiforoff, K. K. (C.C.) “On certain dynamic processes in the soils
of perennially frozen regions” (in Russian and French).
Pochvovedenie
, no. 2, pp.50-74. St. Petersburg, 1912.
15. Obruchev, S. V. “Solifluction terraces and their origin based on
survey in the Chukotsk region” (in Russian
O
^
)
^
Problemy
Arktiki
, no. 3, pp.27-48, no.4, pp.57-83. Leningrad, 1937.
16. Panov, D. G. “Polygonal formations in Kanin Tundra” (in Russian).
State Geographical Society.
Trudy
, vol.65, no.4, 1933.
17. Ratmanov, G. E. “Soils of Novaya Zemlia” (in Russian).
Trudy
of Soil Institute of the Acad. of Sci. USSR. Moscow -
Leningrad, 1930.
18. Rosov, N. “Soils of the USSR.”
Large Soviet Encyclopedia
. Special
volume “USSR,” pp.168-81. 1947.
19. Sergeievskiy, B. A.
Hydrogeographical survey of the southern part
of Kara Sea: Ob-Yenisei region
. (in Russian), 416 pages.
Glavsevmorput. Leningrad, 1936.
20. Sumgin, M. I. “Ever-frozen soils in the USSR” (in Russian), 379 pages.
Acad. Sci. USSR. Moscow, 1937.
21. ----., et al.
General Cryopedology
(in Russian), 340 pages. Acad.
Sci. USSR. Moscow - Leningrad, 1940.
22. Suslov, S. P.
Physical Geography of the USSR
(in Russian), 544 pages.
State Pedagologic Publication. Moscow - Leningrad, 1947.
23. ----.
Olenek River
(in Russian, 165 pages. Glavsevmorput. Leningrad,
1937.
Encyclopedias and periodicals:
<bibl>
24.
Bol’shaya Sovetskaya Enciclopedia
(Large Soviet Encyclopedia) (in Russian),
1927-1947. Ogiz. Moscow.
</bibl>
<bibl>
25.
Sibirskaya Sovetskaya Enciclopedia
(Siberian Soviet Encyclopedia).
4 volumes of which only 3 were available. Siberian Regional
Publication. Novosibirsk.
</bibl>
<bibl>
26.
Problemy Arktiki
(Problems of the Arctic). Monthly. (in Russian)
1937-1940. Glavsevmorput. Leningrad.
</bibl>
<bibl>
27.
Sovetskaya Arktika
(Soviet Arctic). Monthly. (in Russian). 1935-1940.
</bibl>
C. C Nikiforoff