Unpaginated      |      Vol_I-0474                                                                                                                  
(EA-I. (V. A. Obruchev)

GEOLOGY OF SIBERIA

       

CONTENTS

	Page
The West Siberian Lowland	4
Northern Kazakhstan	6
The Altai-Saian region	11
The Kuznetsk Alatau and the Shoria Upland	13
The Salair Ridge	14
The Kuznetsk coal basin	15
The Altai	17
The Western Saian	19
The Minusinsk Depression	20
The Siberian Platform	22
The Yenisei Ridge	26
The Taimyr Peninsula	27
The Eastern Saian	28
The Baikal Sh i eld, the Aldan shield, the Stanovoi Mountains, and the Eastern Transbaikal	29
The Cisbaikal	30
The Baikal Upland	32
The western Trensbaikal	33
The Aldan Plateau	36
The Stanovoi Mountains	37
The eastern Trensbaikal	38

       

-cont’d-

Unpaginated      |      Vol_I-0475                                                                                                                  
Geology of Siberia

(V. A. Obruchev)

        Contents -#2

	Page
The Amur Region and the Southern Maritime Provinces	41
The Amur section	42
The Southern Maritime Provinces	43
Sakhalin Island	45
The Northeastern Region	47
The Verkhoianak-Kolyma section	47
The Chukotka-Anadyr section	51
The Kamchatka Peninsula	53
Bibliography	56

001      |      Vol_I-0476                                                                                                                  
EA-I. (V. A. Obruchev)

       

GEOLOGY OF SIBERIA

        Geological studies of Siberia were less thorough than the investigation

of the Russian Platform, the Urals, and the Caucasus prior to the October

Revolution. A band of some width, along the [ Trans-Siberian - M. E. B. ]

Railway trunk line, was known best; during the period in which the Railway

was built (between 1892 and 1910) several reconnaissance parties, working

from the Urals to Vladivostok, produced a series of maps drawn to scales of

from twenty to forty versts per decimeter. The Altai Mountain region, an

imperial preserve, was studied in rather more detail, but government geologists

were able to produce ten-verst-per - decimeter maps only for the Kuznetsk Basin,

the Salair, the western slope of the Kuznetsk Alatau, and the northern margin

of the Altai before the First World War broke out. Between 1899 and 1913

other geological parties studied the Y e nisei, Lena, Barguzin, and Amur-Maritime

gold areas, and the Minusinak Depression, mapping these areas on a scale of

one or two versts per decimeter.

        In 1912 the Geological Survey began to recruit geologists for local studies,

chiefly of the southern belt, in regions possessing features of special interest,

and also in the Viliui and Aldan river basins, Sakhalin, and the Okhotsk and

Anadyr regions. These field parties filled in the outline of geological data

gathered by the Academy of Science of Geographical Society field parties

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over the vast extent of northern Siberia during a number of years; but their

reports were essentially rather sketchy reconnaissance reports — vast areas

within the regions studied were not examined. Privately sponsored field

parties in the arctic Urals, the Chukotsk Peninsula, and Kamchatka gathered

small amounts of data on these regions at the turn of the century. Thus,

only the southern portions of Siberia had been investigated by geologists

prior to 1917, and even such reconnaissance had not touched the Golodnsia

Steppe of Kazakhstan, the Altai Mountains, and the Western and Eastern Saian,

and these regions remained virtually unexplored. The great northern half of

the country had been crossed only by occasional reconnaissance parties, and

information about the geology of the area was fragmentary and questionable.

        It is worthy of note that only two government geologists were maintained

in all of Siberia before the Revolution; one was attached to the Irkutsk Mines

Administration in 1888, and the other to the Tomsk Mines Administration in

1905. Directives drawn up in 1892 indicate that both used St. Petersburg

as their base of operations.

        A rapid expansion of Siberian geological studies took place after the

Revolution, and as early as 1919, government geologists who were working in

Siberia were unable to return to St. Petersburg across the Civil War front.

They established permanent headquarters at Tomsk and organized for continuous

research. This developed into the Siberian Geological Survey, which later

became the Siberian Department of the Soviet Geological Survey, and, after

a lapse of several years, was combined with the research organization that

had its headquarters at Irkutsk into the Western Siberian Department of the

Survey. Geological activity, centered at Vladivostok, underwent a similar

development. When the Survey subsequently became the Central Geological

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Research and Development Institute, these Departments became first Trusts,

and later Geological Administration s ; such Administrations were established

at Semipalatinak and I Y akutsk, and the Khaberovsk Geological Administration

replaced the Far Eastern.

        Geologists were attached to a number of organizations in the coal,

petroleum, and ferrous and nonferrous metals field s , and undertook special

tasks there.

        The Academy of the Sciences of the U.S.S.R., which led in the study of

the geology of Siberia before the Revolution, continued to send out field

parties for regional stratigraphic, petrographic, geochemical, tectonic, and

geomorphologic studies. The growth of geological research sponsored by the

various geological Administrations and People’s Commissariats was such,

however, that the relative scope of Academy efforts was dwarfed even though

substantial contributions to the study of a number of problems and regions

still came from this source. The efforts of the Russian Geographical Society

in this sphere became insignificant, and research sponsored by private

individuals and concerns disappeared altogether.

        The search for mineral deposits of economic importance held top priority

during the Soviet regime’s first decade; this was due to the urgency of in–

dustrial development. The programming of prospecting for Siberia lagged far

behind. Steps were taken to remedy this situation, and a geological map

(1:1,000,000) of the southern portion of Siberia appeared toward the end

of the decade. Maps drawn to larger scales for various regions appeared,

and maps of assorted merit, drawn to a variety of scales, appeared for the

Kuznetsk Basin, the Altai, portions of Kazakhstan, the Minusinek Depression,

the Kuznetsk Al a tau, the Western and Eastern Saian, the Cis-Baikel Cisbaikal , the Lena

region, and Kamchatka.

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        The Geological Map of the Soviet Union (1:2,500,000), published in 1939,

still contained blank spots, but these are growing smaller.

        We now turn to the progress of regional geological and tectonic studies.

        The West Siberian Lowland occupies the northern half of the area between

the Ural Mountains and the Y e nisei River, and possesses a southward extension —

the Turgai Depression — that lies between the Urals and the Kazakh Steppe.

The fragmentary nature of earlier studies in the area was due to sparse

population and the absence of deposits of the more valuable minerals. The

Soviet period, however, saw considerable progress in the investigation of the

area. Oil possibilities, water supply, potential railway routes, brine lakes,

and peat deposits were studied, as well as moraines and signs of glaciations

in the north, and coal deposits in the Turgai Depression; several geologists

were occupied with those tasks.

        The region’s river valleys were investigated, the suspected eastward

extension of the folding and igneous intrusion of Paleozoic strata in the

Urals were established, while well records and geophysical investigations

along railroad routes revealed that the folded Paleozoic underlies slightly

deformed Quaternary, Tertiary, Cretaceous, and Jurassic formations. Escaping

gas and evidence of petroleum have been found at some points.

        Several field parties also studied the salt, sod s a , and mineral lakes of

the Kulundim and Barsbin steppes; these investigations brought to light a

great deal of information concerning the processes and conditions of salt

deposition and point to the possible future utilization and development by

chemical industries.

        A varied fauna, a not inconsiderable flora, and a large amount of informa–

tion about the Quaternary, Tertiary, local Cretaceous, Jurassic, and Devonian periods

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were gathered in studies of the deep-out valleys of the Irtysh, the Ob, and

their tributaries.

        Several preglacial, glacial, and interglacial stages have been identified

in the regional Quaternary sequence. The Tertiary sequence contains terri–

genous formations of Miocene and Pliocene age, and occasional Paleocene,

Eocene, or Oligocene marine rocks; Cretaceous, Jurassic, Carboniferous, and

Upper Devonian formations, however, crop out only in the Ob Valley above

Novosibirsk. The rich and varied fauna found in the Pliocene rocks near

Pavlodar was described by Orlov.

        A number of investigators penetrated the forested and unforested tundra

west of the Ob and along the western tributaries of the Y e nisei by following

the Taz River. They have studied the glacial and interglacial stages, and

the Arctic Marine Transgression of the Gydan ski and Iamal peninsulas. For example,

by mapping the distribution of erratics, Gromov was able to fix the boundary

between the ice sheet moving down from the Urals and the sheet moving from

the highlands beyond the Yenisei River. The southern boundaries of the

component stages of two glaciations (the Riss, the W u ü rm, and possibly of

an earlier one) are still in doubt, as are the locations of the outlets of

ancient lakes that came into being when moraines damned the Ob and Irtysh.

Gromov found an oil-bearing formation of upper Volga age in the area. Studies

were made of the peat deposits and soils of the tundras and well as their

hydrology and geomorphology. Edelshtein integrated the hydrological date.

        The Quaternary and upper Tertiary strata in the Turgai Depression were

mapped (Paleocene formations frequently outcrop beneath the latter). The

abundant fauna of the Turgai Paleocene was known in pre-Revolutionary times

from studies at Lake Chelkar and along the Dzhilanchik River.

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A. Borisiak of the Academy began to catalogue this fauna at that time, and

he continued the task after the Revolution. Cretaceous and coal-bearing

Jurassic formations crop out locally along the eastern and western borders

of the Depression. The soils and ground water of the Ciz-Aral have been

investigated. Bykov and Baiarunas have described the geology of the area,

and Prigorovski described the coal deposits.

        Tectonic investigations in the area have revealed that the Mesozoic

and Cenozoic formations that cover the more intensely deformed Pale o zoic for

great distances eastward are only locally deformed, and this in the vicinity

of the Irtysh and Ob rivers, where extremely broad folds are present. This

folding becomes somewhat more pronounced toward the Urals piedmont, and is

particularly noticeable in the Rhaetic-Liassic coal measures of the Cheliabinsk

Basin, and in the Cretaceous and Jurassic formations north and south of the

Basin, where relatively recent fault movements have brought up Jurassic,

Cretaceous, and Tertiary formations through varying amplitudes.

        Northern Kazakhstan (Altai Mountains and mining district omitted). The

geological investigation of this region made great progress after the Revolution

because important mining projects were initiated here, and also because flat

relief and the absence of a forest cover make exploration simple. The region,

consequently, is probably the most thoroughly investigated in all Siberia, in

spite of the fact that the structure is extremely complex. The stratigraphic

column carries representatives of every period from the Archean to the Quaternary,

inclusive, and igneous bodies are abundant. The regional pre-Cambrian is repre–

sented by the Archean (gneisses and mica schists) and the Proterozoic (quartzites,

phyllites, sericitic and gra m phitic schists, marbles, and porphyrites); each

section is divided into two unconformable divisions.

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        Middle and Upper Cambrian formations that carry trilobite, archaeocynthid,

and brachiopod fauna, and fossil algae make their appearance in limestones and

shales at various localities.

        The Ordovician and Silurian sequences are even more complete. They are

represented by beds runging from Osarkian to Downt ow nian age, and carry grap–

tolite, pteropod, brachiopod, coral, and other invertebrate remains; limestones

and shales dominate the lithology.

        Extrusive products of submarine volcanism are found together with the

sedimentary Cambrian, Ordovician, and Silurian rocks; thus, fully half the

Cambrian sequence in the Chingiz Range consists of lava analogues which are

also found in central Kazakhstan. The Ordovician also contains tuffs and

volcanic breccias in the latter area, but it is the upper Silurian that contains

the effusives in the Chingiz and Karaganda areas. The volume of effusives in

Tarbagatai and the Ciz-Balkhash is somewhat less.

        Recent studies have revealed the extent of Devonian rocks to be smaller

than had been supposed; paleontological studies revealed that much that had

been considered Devonian in pre-Revolutionary times was really Cambrian,

Ordovician, and Silurian. The lithology of the Devonian, however, turned out

to be more diversified than had been supposed previously; the period saw the

deposition of clays, sandstones, conglomerates, lavas, tuffs, and breccias,

as well as shales and limestones. The Devonian sequence contains, however,

terrigenous deposits in addition to the marine sediments and effusive lavas;

these show that portions of the region were raised during the Caledonian

Revolution. This is borne out by the presence of volcanic lava flows, by the

lithology of the sediments, and the character of Devonian flora that made

their appearance early in the period.

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        A well-developed, richly fossiliferous Carboniferous sequence (that

carries abundant fauna and flora) is represented by marine, lagoonal, and

terrigenous deposits that indicate a continuation and spread of the emer–

gence initiated in Devonian time. (The extent of emergence is measured by

the extent of coal.) The lithology of the Carboniferous is even more

diversified than that of the Devonian; claystones, coals, gypsum, and

limonite appear in the stratigraphic column together with the characteristic

limestone, shales, marls, sandstones, and conglomerates. Lavas, volcanic

breccias, and tuffs of lower and early-middle Carboniferous age are found

throughout the region, but upper Carboniferous extrusives are confined to

it southeastern portion.

        Recent studies have established the presence of Permian formations in

Kazakhstan; this series is represented by the Kalbinsk Range coal deposit,

the Kenderlyk oil-shale deposits in the Saur Mountains (these carry a fish

and pelecypod fauna), and the fossil-bearing marine formations on the shores

of Lake Zaisan-Nor. The fish and pelecypod fauna in the copper-bearing

sandstones that lie unconformably upon the Carboniferous rocks in central

Kazakhstan fix the age of the former as Permian.

        These Paleozoic faunas and floras were classified and described, in part,

by a number of Soviet paleontologists, including, in particular, Gorski ,

Krishtofovich, Nalivkin, and Nekhoroshev.

        No Triassic rocks have been observed in Siberian Kazakhstan, and it is

improbable that any will be found, inasmuch as the Permian marine sediments do

not extend west of points east of Lake Zaisan-Nor. The sea had retreated

eastward, and only embayments reached westward to the Irtysh valley. The

Permian formations are terrigenous over the rest of the region. The Cheliabinsk

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Basin coal measures, however, are uppermost Triassic (Rhaetic). The entire

region consisted of dry land through the upper Permian, the Triassic, and

the Jurassic, and it was only in late Jurassic time that a marine trans–

gression moved southward, parallel to the Urals piedmont.

        The Jurassic is represented by sandstones, shales, claystones, con–

glomerates, and a variety of plant-bearing coal deposits, as well as the

fossil clays and bauxites of an ancient zone of weathering; these lie here

and there unconformably upon Paleozoic rocks. The cola deposits of Karaganda,

Dzhezkaggan, Kiakta, and Baikonur are of Jurassic age; they lie on top of

Permian rocks at Kenderlyk and at some points west of the Irtysh.

        Lower Cretaceous marine formations crop out north of the Aral Sea;

Upper Cretaceous formations crop out along the eastern margins of the Turgai

Depression, and also appear in the vicinity of Pet r opavlovsk on the Depression’s

northern slopes. (This information was discovered by means of drilling.)

In central and eastern Kazakhstan, Cretaceous red conglomerates and finer

grained sedimentary rocks fill ancient valleys and underlie early Cenozoic

formations.

        Red, yellow, and white Tertiary conglomerates, sandstones, marls, clays,

kaolins, sands, and gypsums are found in ancient valleys and depressions. In

places these formations form lines of hills (in the vicinity of the Saur

Mountains), or form divides between valleys, as along the Black Irtysh or

in the Golodnaia Steppe (at Bedpak-tala). There are localities, for example,

Mount Ashu-tas along the Irtysh, at which a rich Oligocene-Miocene flora is

found. Other localities carry remains of upper Oligocene, Miocene, and

Pliocane vertebrates, and still other localities carry symptoms of Tertiary

marine conditions.

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        The regional Quaternary is represented by deltaic, overbank, rainwash,

and stream-bed deposits. These include forest soils, gravels, sands, and

clays of river terraces; as yet, these deposits have not been investigated

thoroughly. Manual remains are found occasionally.

        A variety of intrusive bodies and veins connected with a number of

tectonic movements have invaded the pre-Cambrian and Paleozoic formations in

the region. Basic and ultrabasic rocks are the hallmark of the pre-Cambrian

here, and two alkaline granite intrusions associated with two tectonic move–

ments are present. The Salair and Teconic phases of the Caledonian Revolution

were accompanied by the injection of granodiorites, while the upper Silurian

phase saw the injection of great volumes of basic and ultrabasic rocks. Early

Variscan movements were accompanied by granodiorite and biotite-hornblende

intrusions (mid-Carboniferous), while the injected bodies associated with the

later Permian phases of the Variscan orogeny consisted of alkaline granites

and other alkaline rocks (nepheline syenite, te a s chenites, pantellerite,

anorthoclase - rich rock species).

        West of the Irtysh these intrusive rocks are replaced by extrusives that

cover the lower Permian terrain, and they may be of lower Mesozoic age. The

only indication of later volcanism is a group of basalt dikes in the Kalbinsk

Range. Other Paleozoic extrusives have been mentioned above; these tend to be

alkaline rather than acid.

        The structure of the region is the product of two pre-Cambrian tectonic

movements, four orogenic stages of the Caledonian Revolution, and four orogenic

stages of the Variscan. These structures are the geosynclines, monoclines, and

raised platforms that have characterized the tectonics of Kazakhstan since

Paleozoic time. Zones of folding have been developed in the geosynclines and,

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to some extent, upon the monoclines; brachyfolds and domes have been developed

on the monoclines.

        Post-Permian vertical oscillations occurred in the Upper Jurassic, in

the mid-Cretaceous after the end of the Turonian epoch, and at the end of

Cretaceous time. The marine waters that commenced their advance from the

north, along the foothills of the Urals, in late Jurassic and early Cretaceous

time, reached Kazakhstan in Tertiary time, and involved the region in the

general downsinking, transforming it into an archipelago. Uplift at the end

of Oligocene time reestablished dry land conditions. All of the movements

associated with the Alpine orogany were vertical oscillations, though fault

movements occurred in some places; these latter continued as late as Pliocene

time, and even into one of the interglacial stages.

        It is worthy of note that the dimensions and distribution of the region’s

folded zones is the subject of a dispute between Kassin, who draw the first

tectonic ma n p of Kazakhstan, and Shatski , who used materials gathered by

Academy of Science s field parties to draw a different map.

        Gornostaev, Eliseev, Kassin, Nakovnik, Nekhoroshev, Rusakov, Satpaev,

Shligin, Iagovkin, and Iskovlev have made perhaps the most substantial con–

tributions to the study of the geology of the region.

        The Altai-Saian region embraces the Altai and Kuznetsk Alatau, the Salair

Mountains, and the Western Saian, and the Kuznetsk and Minusinsk basins that

lie among these ranges. The western boundary of the Altai-Saian region runs

through Novosibirsk district, and the eastern boundary runs through Krasnoiarsk and

Yenieeisk districts. Formerly, this area was known in the most general way,

investigations having been confined to areas that lie along the Trans-Siberian

Railway trunk line. The geologists of the Imperial Geological Survey ascer–

tained the general nature of the Kuznetsk Basin and the mountain ranges that

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surround it; Survey geologists also explored various portions of the

Minueinsk Basin and the eastern slope of the Alatau. The Altai mining dis–

trict was known from reports compiled by the district’s many mining engineers,

but the only data on the Altai Mountains and the Western Saian consisted of

reports of infrequent travelers. After the Revolution, however, the geological

investigation of this great and tectonically complex area forged ahead at

greatly increased tempo because of intensive prospecting activity by the

Western Siberian Department of the Soviet Geological Survey (later the

Geological Administration).

        Mesozoic and Cenozoic continental deposits, in general, and the great

Jurassic coal series of the Chulym-Yenissisk Basin, in particular, dominate

the flat and gently rolling areas that constitute the northern portions of

the region. The A lower [?] Carboniferous Minusinsk series, outcrops beneath

the Jurassic formations along at the southern edges of the basin. Pre-Cambrian, Cambrian,

Silurian, and Devonian deposits, as well as some igneous rock bodies, are

found in an ancient horst structure in the Arga Range near Achinsk, and con–

statute the most important outcrop in the Chulym area. Cambrian, Ordovician–

Silurian, Devonian, and some pre-Cambrian rocks outcrop in the Kemchugsk

Mountains, between Achinsk and Krasnoiarsk. Devonian coals are found on the

western shore of the Yenisei River, southwest of Krasnoiarsk. The Jurassic

formations are overlain by plant-bearing Upper Cretaceous beds at some

localities, and small, widely scattered areas of Tertiary deposits are also

preserved.

        West of Tomsk, Taiga, and Novosibirsk, a Carboniferous-Permian coal series,

Upper Devonian and lower Carboniferous marine sediments, and Cretaceous con–

glomerate underlie plant-bearing Tertiary (Eocene and Miocene) and Quaternary

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sediments; massive granites outcrop along the Ob near Novosibirsk.

        The region’s pre-Cambrian and Paleozoic rocks are intensively deformed,

whereas the Mesozoic and Cenozoic rocks have been subjected to gentle, local,

and shallow folding. Late Variscan granite intrusions are also present.

        Korovin’s work on the Yenisei-Chulym Basin is notable, as is Vasilev’s

work on the Arga Range.

        The Kuznetsk Al a tau and the Shoria Upland have been quite thoroughly

examined by a number of investigators, because rich mineral deposits (gold and

iron in particular) are present in the area. Pre-Revolutionary investigators

recognized the fact that pre-Cambrian rocks dominate the regional lithology,

and belong to a range of rock types that extends from gneisses to a variety

of schists. During the early years of the Soviet regime, geologists were inclined

to regard all of the pre-Cambrian rocks as metamorphosed Cambro-Ordovician, but

careful studies of excellent outcrops along several of the local rivers revealed

that wisespread Archean rocks, wedged into early Paleozoic formations by compli–

cated tectonic movements, are present, as well as Proterozoic limestones, schists

and extrusives. Rocks formed during all three divisions of the Cambrian period

(Lowe, Middle, and Upper), with their characteristic faunas, as well as Ordovician

rocks and fossil-bearing Silurian rocks, lie atop Archean and algal Proterozoic

rock, and constitute the main mass of the Alatau together with the Shorian Upland.

The rocks of Devonian age, on the other hand, are preserved in some grabens, but

in the main, outcrop with lower Carboniferous formations along the borders of

the Alatau and in the Shorian Upland. A Permian coal series, Jurassic forma–

tions with plant remains, and Tertiary formations are found along the edges

of the Alatau, as well as Jurassic and Tertiary gold-bearing conglomerates.

Records of two glaciations, which include a number of glacial lakes, are found

in the upper Alatau.

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        The abundant pre-Cambrian and Paleozoic intrusive bodies in the area

consist of pyroxenites, labradorites, gabbros, gabbro-syenites, gabbro–

diorites, granodiorites, granites, and “proterobases.” The region’s

extrusives (melanophyres) are also of pre-Cambrian and Paleozoic age.

        The breaks and unconformities between various formations indicate a

number of pre-Cambrian, Caledonian, and Variscan tectonic movements; the

exact number of movements is still in dispute, however.

        The first folds observable in the Alatau appeared in pre-Cambrian and

early Paleozoic time; these were washed into shallow Devonian seas. Later

block movements caused folding, intrusion, and extrusion at the margins of

the region.

        The work done in this region by Bazhenov, Bulynikov, Derbikov, Kuzmin,

Lebedev, Monich, Radugin, Usov, and Churakov should be noted.

        The Salair Ridge is the southwestern margin of the Kuznetsk Basin. Here,

too, more recent prospecting for polymetallic gold, iron, and bauxite deposits

brought about intensive geological exploration. Formations of late Proterozoic,

Cambrian, Ordovician, Silurian, and Lower, Middle and Upper Devonian enter

into the stratigraphy of these mountains; marine lower Paleozoic, marine

lower Carboniferous, and terrigenous middle and upper Carboniferous formations

outcrop at the margins of the ranges. (The last two types are found in the small

Gorlovsk and Eltsov s k coal basins.) Devonian rocks also outcrop at the edges

of the coal basins. Questionable Meso c z oi z c deposits as well as Tertiary lake

deposits are found at some localities in these areas. The entire regional

Paleozoic is intensely deformed and intruded by granites, quartz nordmarkites,

oligoclasite s , albitophyres and diorite-diabases; the Cambrian, Ordovician,

Silurian, and part of the Devonian stratigraphic column include lavas and tuffs.

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Materials were also gathered on Quaternary deposits, ancient bau z x it o ic zones

of weathering, soils, and peat deposits.

        The complexity of the tectonic structure of the Salair Mountains is

cause for considerable disagreement among geologists. Proterozoic, Caledonian,

and Variscan geosynclinals folding is clearly present. A thrust along which

Cambrian rocks overrode Devonian formations has been identified on the eastern

margins of the area. The fundamental tectonic structure of the area is

presumed to be a great eastward thrust of Sudetian age.

        The Devonian and Carboniferous are intensely folded, faulted, and overthrust

in the Gorlovsk Basin. Block faulting occurred in the region during the Cenozoic;

these movements, together with weathering processes, gave the Salair its

present relief.

        The outstanding students of the area are Bolgov, Bulynikov, Derbikov,

Lobazin, Lopushinski, Speranski, Usov, and Iavorski.

        The Kuznetsk coal basin attracted the attention of a great number of

geologists because the earliest Soviet investigations revealed that the volume

and quality of the local coals had no equal in the Soviet Union. For this

reason detailed maps for a number of mining localities appeared simultaneously

with the first general geological map of the region. Butov’s and Iavorski’s

over-all reports on the area appeared in 1927, Fomich’s over-all report

appeared in 1940, and 1941 saw the appearance of the Kuznetsk Basin Volume

of the Geology of the U.S.S.R. in which a number of geologists contributed

to a detailed analysis of the area.

        The basin separates the Salair Ranges from the Alatau; the Shorian Upland

forms a lower southern margin of the basin. Intensely deformed Cambrian,

Ordovician, Silurian, Devonian, and lower Carboniferous formations outdrop

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outcrop along the eastern margin of the basin, while slightly disturbed

Devonian and lower Carboniferous formations are found to the south and the

northwest. The coal deposits occupy the interior of the basin, and represent

the middle and upper Carboniferous, lower and upper Permian, Triassic, and

Jurassic formations. The degree of deformation of the strata decreases from

the margins of the basin inward. Porphyry and disbase intrusions are found

in the lower Paleozoic rocks along the eastern margins of the basin, while

basalt sills are intercalated in the Triassic and Jurassic rocks, on both

sides of the Tom River, in the mountains of the so-called “melaphyr horsehoe.”

        Soviet geologists have worked out the detailed straitgraphy of the area.

Abundant fossil faunas and floras fix the age of the main coal beds as

Carboniferous and Permian, and establish the presence of Triassic and Jurassic

sequences that contain coal beds, contrary to the older impression that all the

coal deposits are of Permian age.

        The structure of the basin has been formed by repeated pressure from the

Kusnetsk Alatau on the east and the Salair on the southwest. The Carboniferous,

Permian, and Triassic beds are conformable. The first regional folding of the

basin is ascribed to the early Cimmerian Kimmeridgian epoch of folding since the Jurassic

beds lie with mild angular unconformity upon the Triassic. The Jurassic and

earlier beds have been more intensely deformed by a later orogenic movement

that was accompanied by outpourings of basalts. It has been assigned tenta–

tively to a late Cimmerian Kimmeridgian orogenic epoch. Overthrusting is quite common

along the margins of the basin, but it diminishes toward the central areas.

It seems that the region occupied by the Kuznetsk Basin was a quiescent

syncline in early Carboniferous time, after intense Caledonian and early

Variscan folding. The thickness of the sediments and the large number of

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coal beds indicate that slow, spasmodic sinking was the only tectonic move–

ment up to the end of Triassic time. Longitudinal faults in the Kuznetsk

Alatau and the Salair determined the boundaries of the syncline and facili–

tated the downsinking. Finally, post-Jurassic block faulting in both ranges

deformed the sediments once more.

        Among the many geologists who have worked in the Kuznetsk Basin, the

most significant contributions were made by Adler, Butov, Dorofesv, Ergolsk i a ia,

Kumpan, Neiburg, Usov, Fomichev, and especially, Iavorski. The fossil faunas

were described by Pagozin, Khalfin, Chernyshev, and Ianishevaki; the fossil

floras were described by Zalesski, Neiburg, Rad i chenk i o , and Khakhlov.

        The Altai constitutes the southern half of the Altai-Saian region. The

southwestern portions of the Altai were known rather thoroughly before the

Revolution, inasmuch as mining operations had been conducted there since the

seventeenth century; the rest of the area was known only from the occasional

writings of travelers. The mining region, because of its economic importance,

was the object of intensive study by Soviet geologists. Detailed reports

about almost every part of the area exist, but only a few of these have been

published. The Altai Mountains have been investigated less thoroughly than

any other section, but the discovery of a variety of economic deposits valuable ores will

necessitate exhaustive studies there as well.

        The presence of intensively metamorphosed pre-Cambrian rocks that include

small bodies of rock which may be Archean in age has been established; for the

most part, however, the pre-Cambrian rocks are Proterozoic and include

several thick patches of tillites, that is, metamorphosed boulder clays that

point to very ancient glaciations. Considerable thicknesses of Cambrian marbles

and fossil-bearing shale are present, but these are overshadowed by the thicknesses

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of Ordovician and Silurian fossil-bearing shales and limestone roofs.

Smaller thicknesses of Devonian terrigenous marls and red sandstones lie

unconformably upon the pre-Devonian sequence of rocks. In the valleys of

the Bia and Chuia rivers, to the northward, narrow, squeezed-in bands of

lower Carboniferous and Permian coal-bearing formations are found. Patches

of coal-bearing rocks of Tertiary age are found along the Chuia and Argut

rivers.

        The geology of the Altai mining district is quite different; the

section’s pre-Cambrian and Cambrian rocks have not been examined yet, but

it has been established that the dominant local rocks are metamorphosed

Silurian, and marine Devonian, Carboniferous and lower Permian. Coal-bearing

rocks of Tertiary age have been found only on the Narym River.

        A great variety of intrusive and extrusive rocks of various ages con–

stitutes an important component of the lithology of both sections of the

Altai. A number of granitold bodies are present; these frequently pass over

into porphyries. Basic rocks are present in smaller volume. The tectonic

structure of the Altai Mountains, also, is different from that of the mining

district; in the former section a Caledonian folding that strikes NW. -SE.,

but swings to a N E.-SW. Strike in the eastern part of the section dominates

the Paleozoic structure. The Devonian rocks are less intensely deformed, and

the Tertiary formations were disturbed by much more recent black movements.

        All of the Paleozoic folds in the Altai mining district strike NW. -SE.;

these folds, however, are cut by two zones of crumpling that strike EW. -SE.,

and follow the faults at the margins of the Paleozoic geosyncline in which

great thicknesses of Devonian, Carboniferous, and early Permian sediments

accumulated, and were intruded by great bodies of Permian granite.

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        V. A. Obruchev originally pointed out that the entire folded structure

of the Altai was completed in Paleozoic time. The region was almost base–

leveled in Mesozoic time. Cenozoic block faulting produced renewed uplift

in the region. This fact of block faulting accounts for the occurrence

of coal-bearing Permian formations as wedge-shaped outcrops among fault

lines, and for the upraised and somewhat folded condition of the local

Tertiary formations.

        Quaternary and recent glaciations have been studied in the Altai in

considerable detail. One, or possibly two, glacial stages have been identi–

fied that antedated the Rise and Würm stages; the earliest of the regional

glaciations out into a different and less rugged terrain.

        The most significant contributions to the store of information on the

geology of the Altai were made by Baklakov, Boldyrev, Bublichenko, Origprev,

Eliseev, Kotulskii, In. A. and V. A. Kuznetsov, Markhilevich, Nekhoroshev,

Padurov, the Tronovs, Churakov, and Shakhov. (The description of the Paleozoic

fauna is lagging far behind the geological field investigations.)

        The Western Saian is the eastern continuation of the Altai Mountains.

Investigations have brought to light a wealth of new data. Red metamorphic

rocks of pre-Cambrian age seem to dominate the lithology of the region; smaller

sequences of Cambrian, Ordovician, Silurian, and Devonian rocks are also present.

Closer scrutiny, however, reveals that the regional Proterozoic component is

relatively minor, and that the greater part of the metamorphic and red rocks are

Lower and Middle Cambrian and Ordovician. In fact, it is the Cambrian and

Silurian formations that turn out to dominate the regional stratigraphy. Three

bands of iron-bearing quartzites represent the Silurian period. A Devonian

sequence, the Minusinsk series of the lower Carboniferous, and upper Carboniferous–

Permian coal-bearing formations are present in the northern foothills. The

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supposed Triassic marine formations along the Us River constitutes a highly

problematical case, inasmuch as they were first dated on the basis of a poorly

preserved fossil fauna, and the dating was never verified. The intrusive

bodies found in the region are of Caledonian age, and possible pre-Cambrian.

A belt of Salair (Upper Cambrian) serpentines constitutes an ultrabasic

component of the regional lithology. The local extrusives are said to be

mainly Silurian. An examination of the local Quaternary formations indicates

two glaciations.

        The tectonics of the Western Saian are as follows: The Variscan orogeny

compressed and overturned Cambrian and Ordovician folds that had been thrown

up in the course of Caledonian movements. These overturned folds were thrust

for great distances over upper Paleozoic rocks along the edge of the Minusinsk

Basin. Like the Altai Mountains, the Mesozoic and Cenozoic orogeny in the

area consisted of block faulting; these movements give the region its present

rugged relief.

        The greater part of the material on the geology of the Western Saian

has been collected by Bazhenov.

        The Minusinsk Depression is bounded on the west by the Kuznetsk Alatau,

on the south and east by the Western Saian, and on the north by the Eastern

Saian and the Solgon R r anges. The presence of copper, iron, gold, and asbestos

deposits attracted the attention of pre-Revolutionary geologists to the

region. Soviet geologists have continued the study of these deposits, dis–

closed the existence of now economic other deposits, and indicated the possible

presence of oil pools and salt. Maps have been issued and a great deal of

information collected, but several important problem still remain unsolved.

        Two ranges that trend ENE. -WSW. divide the Depression into three basins.

Pre-Cambrian and lower Paleozoic rocks outcrop in the ranges; middle and upper

Paleozoic rocks occupy the basins. The Proterozoic period is represented by

limestones, graywackes, and siliceous slates; the sediments are intruded by

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granites, gabbros, and porphyries. (A number of investigators regard this

sequence as Cambrian.) The limestones carry algae and erratics that were

presumably dropped from icebergs during a glacial epoch. The local Middle

and Upper Cambrian limestones contain algae and a fossil fauna, and are

intruded by diabases and porphyries. A series of tuffs and porphyries is

tentatively dated as Silurian. The sea retreated from the area in Silurian

time, but returned for a short time in the Devonian. The Lower Devonian rocks

are red plant-bearing sediments and effusive; the Middle Devonian sequence

begins with plant-bearing oil shales, while limestones with a marine fauna

constitute its upper portion; the Upper Devonian rocks are red terrigenous

sediments with fossil r f ish remains and plants. The Minusinsk series, which

some writers regard as lower Carboniferous and others as Upper Devonian

(on the basis of the fossil plants present), overlies the major Devonian

sequence. The Minusinsk series, in its turn, is overlain by a coal-bearing

series the age of which is still in doubt (upper Carboniferous or lower

Permian). Coal-bearing Jurassic rocks are found in the northernmost basin.

Tertiary deposits are minor. The Quaternary period is represented by sands

and loosses that contain plant remains and human artifacts.

        It is doubtful whether Proterozoic folding movements took place in this

region as there does not seem to be a regional break between Proterozoic and

Cambrian sediments. The Caledonian folds have clearly geosynclinals character

and are contemporaneous with adamellitic and basic intrusions. Variscan

movements produced en e é chelon fold and domes in the basins of deposition

where Devonian, Carboniferous, and Permian sediments had accumulated. The

major faults at the margins of the depressions (occasionally associated with

thrusts and extrusives) had their origin in Caledonian movements, but are

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largely the products of Variscan orogeny. The Jurassic beds in the northern–

most basin were deformed during a later orogeny.

        The chief contributors to the geological literature of the Minusinsk

Depression are Bulynikov, Vologdin, Domarev, G. A. Ivanov, Krubetov, Churakov,

Shamanski and Edelshtein. Gromov’s and Sosnovakii’s studies of the region’s

Quaternary formations are noteworthy.

        The Siberian Platform is bounded by the Eastern Saian on the south, by

the Yenisei Ridge on the west, and by the Taimyr Peninsula on the north.

Formerly, adequate data were available only on sections that lie in the

southern quarter of the Platform along the Trans-Siberian Railroad, in the

Yenisei gold mining district, along the Lena River, and in parts of the Viliui

River basin. The rest of the area was known only from the reports of occasional

field parties, and some of them very old. Recent investigations were carried

out in the coal fields of the Irkutsk, Kan, and Tunguska basins, the

Angara-Ilim iron district, the Norilsk pyrite deposits, the Viliui and Gulf

of Khatanga rock-salt deposits, and the Yenisei gold fields. The wartime

discovery of oil-trap structures in the Anabar Massif, the Viliui Basin, and

the Severnaia Zemlia Islands attracted a number of geologists to these areas.

Thus, virtually the entire Platform has been investigated, and even the Eastern

Saian, long a blank spot upon the map, has seen the day of its geologic mapping.

        The pre-Cambrian foundations of the Platform outcrop, at the margins, in

the Yenisei Mountains Ridge , the Eastern Saian, the Cis-Baikal Cisbaikal R r anges, and the

Anabar Massif. The last-named massif, incidentally, was discovered by the

Baklund-Tolmachev expediton of 1905-1907, but is was not described geologically

until recently.

        It is made up of Archean charnockite gneiss, granulites, and amphibolites.

These metamorphic rocks have been intruded by granite bodies and associated

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offshoot veins, and basic dikes. Archean and Proterozoic rocks also outcrop

in the marginal areas which we shall discuss presently, and there is no

reason to doubt that they underlie the entire Platform. Cambrian, Ordovician,

and Silurian rock lie unconformably upon the pre-Paleozoic complex. They

have been studied by geologists in various degrees of detail. Lower, Middle,

and Upper Cambrian formations have been found on the Platform; the Middle

Cambrian limestones dominate the stratigraphic sequence of the Cambrian.

Calcareous and red-colored Ordovician and Silurian formations follow, the

latter indicating a withdrawal of the sea in the northern portion of the

Platform. This conclusion is supported by the fact that the Devonian forma–

tions in the Bakhta, lower Tungueka, and Kureika River valleys, near the

Yenisei River are colored red also. A Givetian (late Middle Devonian) marine

sequence is also found in the Bakhta Valley, however, and Frasnian (Upper

Devonian) limestones that carry corals and brachiopods are found in the Kheta

River basin. The mid-Devonian marine transgression does not appear to have

penetrated very far to the south. Fossil-bearing lower Carboniferous

(Tournaisian) marine strata are found along the Kureika and Tunguska rivers.

The sea retreated a great distance to the north in lower Carboniferous times,

and land conditions prevailed on the Platform from Visean through Liassic time.

        The terrigenous upper Carboniferous and Permian Tunguska series lies

uncomformably upon early and mid-Paleozoic formations. It extends southward

along the Angara River, and almost reaches the Eastern Saian in the Kan River

basin. A study of the Tunguska series was not undertaken until recently, when

it was separated into the productive, the r t uff, and the lava-tuff divisions.

These investigations also revealed data on the fossil flora, the coal and

graphite deposits, and the olivine-diabase trap intrusions and extrusions.

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The major area occupied by the Tunguska series has been termed the Tunguska

Basin and contains vast coal and graphite deposits. It extends eastward

into the Viliui River basin, as far as the Chona Rive.

        Jurassic beds lie upon Paleozoic in the eastern portions of the Viliui

River basin; these were identified by Rzhonenitskii before the Revolution,

but have been studied in detail recently by geologists. The Lower Jurassic

formations are fresh-water sediments, the Middle Jurassic formations are

marine (ingression by seas from the north), and the Upper Jurassic formations

are terrigenous and coal-bearing. These rocks extend to the southern Lena

Valley, where studies of the coal deposits have been made between Kangalas

and Bulun. Farther north along the arctic littoral, Lower, Middle, and Upper

Triassic outcrops have been studied in the lower Olen s e k River valley, east

of the Gulf of Khatanga. Rhaetic-Liassic deposits that carry a fossil flora

are overlain by a later Jurassic marine sequence which, in its turn, is

overlain by coal-bearing Cretaceous sediments. This sequence is found farther

west, in the Khatanga Depression. Marine Devonian formations that overlie

early Paleozoic sequences are found to underlie Mesozoic strata at Solianaia

Sopka. This area contains deposits of rock salt , and pools of oil trapped natural gas, and oil.

against e S alt domes are numerous.

        A Jurassic terrigenous sequence that contains deposits of coal and jet

lies directly upon early Paleozoic formations in the southern half of the

Platform (in the so-called Irkutsk Amphitheater). This sequence was studied

in the Irkutsk and Kan River basins (the Tunguska series outcrops at the margins

of the latter section), as well as in the less extensive Khakherei Basin

farther north, where oil shales and coals are found. Tertiary terrigenous

deposits are rare on the Siberian Platform. The deposits at of Quaternary age

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EA-I. Obruchev: Geology in Russia of Siberia

found in the southern sections of the platform have been studied in much

greater detail, because of the presence of building materials there. Two

glacial stages have been identified in the northern part of the Platform

(the Tunguska Basin), and three glacial stages, plus two interglacial

marine transgressions from the north have been identified in its northeastern

sections.

        Except for the extrusive rocks in the pre-Cambrian complex in the Anaber

Massif, traps are the only rocks of this type on the Platform. The main

concentration of traps is in the Tunguska Basin, but they are also found

in the Viliui River basin, to the east, and in the Irkutsk and Kan River

basins, to the south. The main outpourings of molten lavas occurred in

Permian time, but bursts of igneous activity occurred in Mesozoic, and possibly

even Tertiary time. Attention may be called to the A a lkali gabbro intrusions

along the Kheta River which are composed of ijolites and melteigites, and

associated extrusives chiefly augi i tic, melilitic, and limburgitic basalts;

the age of these igneous rocks is probably late Mesozoic.

        Tectonically, the Siberian Platform is a great area of undisturbed

Paleozoic rocks that are deformed only at the Yenissi, Eastern Saian, and

Cis-Baikal Cisbaikal margins, where the strike of the folding parallels the strike

of the pre-Cambrian outcrops. The Cambrian rocks are slightly raised at

the margins of the Anabar Massif. The structure of the interior of the

Platform consists of extremely gentle folds in the Paleozoic rocks; rarely

does one see such gently rolling structure. Movements in the basement complex,

however, have generated shallow basins in the Viliui, Yenisei, and Saian sections

Both the Tunguska series and the Jurassic strata are folded in the Viliui

Basin, and at some points in the Irkutsk Basin. The main folding on the

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Platform was of Caledonian date, though the Variscan Revolution produced

folding and faulting in the Tunguska Basin; the traps poured out along the

faults produced at that time. The Mesozoic era was a time of regional

oscillations that brought in Jurassic seas from the north and formed lakes

in the south; some weak folding also resulted. Oscillation continued into

Tertiary time.

        The contributions of the following geologists stand out among the

many studies conducted in the area: A. I. Gusev, A. A. Grigorev,

Zhemchughnikov, Zegebart, Korovin, Levinson-Lessing, Maslov, Moor, S. Obruchev,

Otten, V. Sobolev, Tebenkov, Frishenfeld, and Iarahemeki.

        The Yenisei Mountain Ridge north of the Angara River had been investigated

in considerable detail previously; the southern third of the mountain system

(south of the Angara) was known only roughly, however. Soviet research

concerned itself with the entire mountain system. A great Proterozoic

sequence that consists of series of metamorphosed slates, quartzites, and

limestones, topped by tillite, has been established here. Archean gneisses

and schists dominate the lithology south of the Angara River. These rocks

outcrop at some localities north of the Angara also; in any event, they are

close to the surface here. Local sequence of Lower Cambrian red sediments,

conglomerates, and sandstones are found, and Cambrian, Ordovician, and

Silurian deposits outcrop along the flanks of the mountains. The Archean

and Proterozoic rocks are intruded by granite bodies and associated veins.

Islands of coal-bearing Jurassic rocks are found in the central third of the

mountain system. Evidence of weak glaciations is found in the north.

        Proterozoic folds strike NW. -SE. and cut the Yenisei River at an acute

angle. Caledonian folds of Cambrian, Ordovician, and Silurian strata are

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pressed against both sides of the mountain system and faulted on a major

scale.

        Gornostaev, In. Kuznetsov, I. G. Nikolaev, S. Obruchev, and Shchukin

are probably the leading students of the era.

        The Taimyr Peninsula is separated from the Siberian Platform by the

Khatanga-Yenisei Depression. The area was hardly known before the Revolution,

and the adjacent Severnaia Zemlia Archipelago had just been opened. Outcrops

of pre-Cambrian granites, gneisses, mica schists, phyllites, and cherts are

found along the arctic coasts. Farther south these metamorphics are replaced

by outcrops of Ordovician and Silurian formations and rocks of the Tunguska

series with intruded traps. This complex constitutes the Byranga Plateau.

The Piasina River basin, to the west, is made up almost entirely of coal-bearing

formations of Tunguska age; marine deposits of Cretaceous age are also found

along the Yenisei River in this area. Upper Devonian (Fraenian) and lower

Carboniferous formations outcrop in the Efremov a s k uplift section; the basal

Tunguska beds are marine here. Lower Cambrian conglomerates cover the

Proterozoic metamorphosed slates on the Cheliuskin Peninsula, while all

three divisions of the Cambrian period are represented in the Severnaia Zemlia

Archipelago. The Quaternary period is represented by the moraines of two

glacial advances and the sediment laid down during one interglacial marine

transgression from the north.

        There is considerable disagreement about the tectonics of the Taimyr

Peninsula. Early investigators in the area thought that a great thrust

movement had moved a mass of crystalline rocks over an Ordovician-Silurian

terrain, and had thrust the overridden Ordovician-Silurian rocks over a

Tunguska series terrain. The fault system was supposed to strike ENE.-WSW.

Subsequent investigations, however, have shown that the Caledonian folds were

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EA-I. Obruchev: Geology in Russia of Siberia

overturned to the south, and that the regional fault system is characterized

by smaller displacements and is of Variscan origin. The folds swing to a

NE.-SW. and N.-S. strike on the Cheliuskin Peninsula, and assume a NNE.-SSW.

and NW.-SE. strike in the Severnaia Zemlia Archipelago; thrust faulting

complicates the structure in the latter section. The main orogeny in these

areas is also Caledonian and was accompanied by the intrusion of granite

bodies; the Variscan movements were accompanied by intrusion and extrusion

of trap. Mesozoic and Cenozoic movements were oscillatory.

        Aller, Anikeev, Baklund, Liutkevich, Mutafi, Smirnov, and Urvantaev

have made significant contributions to the study of the geology of the Taimyr

Peninsula.

        The Eastern Saian was as little known as the Taimyr Peninsula. Investi–

gation of the area was undertaken on a large scale in the middle 1930’s;

geological maps published in 1934 still contained large blank areas. The

now data indicate that Archean gneisses and amphibolites dominate the lithology

of the region. Proterozoic phyllites, sandstones, and limestones are second

in importance; these have been grouped into three series. The aggregate

thickness of the Proterozoic rocks is twenty kilometers (66,000 feet).

Cambrian shales, phyllites, sandstones, and limestones with subordinate

tuff and lava beds are present, in which an early and Middle Cambrian fossil

fauna has been found. The uppermost strata of this sequence may be Ordovician,

however. The volcanic rocks are generally taken to be Silurian-Devonian.

Marine conditions terminated in the Western Saian in Cambrian, or at the

latest, in Ordovician time. The Devonian period is represented by terrigenous

red sandstones and conglomerates of small thickness and lateral extent. At

two localities plant-bearing Jurassic lake deposits rest directly upon an eroded

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pre-Cambrian surface. The Tertiary period is represented by conglomerates

that contain argillite lenses with Miocene plant remains. Those are over–

lain by a Quaternary basalt-moraine-basalt sequence.

        The tectonic structure of the Eastern Saian is the product of Archean

and Proterozoic orogenic cycles; these included acidic and basic intrusions

and extrusions. There was no Caledonian geosyncline in the southwest, and

the northeastern portion of the region was part of an uplifted plateau. The

pre-Cambrian folds strike NW. -SE. whereas the Caledonian folds to the west

strike N W E .-SW. In Devonian time, land bridges that connected the entire

Saian to the Siberian Platform existed. Subsequently, the only tectonic

movements that occurred in the area were faulting, monoclonal flexuring, and

stage-by-stage regional uplift. The present relief of the region was determined

by basalt flows that filled the valleys in Quaternary time. Subsequent

studies have shown that previously inferred thrusts do not exist in the

region.

        Bazhonov and Vologdin have done valuable work at the western end of the

mountain system; Konoplev, Molchanov, S. Obruchev, and N. Scbolev made the

most significant contributions to the geology of the greater portion of the

system, and S. Obruchev, after a three-year study, synthesized and interpreted

the tectonic and stratigraphic data of the region.

        The Baikal Shield (the Ancient Roof of Asia), the Alden Shield, the

Stanovoi Mountains, and the Eastern Trans -B b aikal . Some parts of this region

were thoroughly known before the Revolution, other parts were known incompletely,

and still others were altogether unknown. The southern half of the Trans -B b aikal

was studied by a great number of field parties in connection with the construc–

tion of the Trans-Siberian Railroad; the northern half was less intensively

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studied. A map (1 :4 2,000) of the Lena gold mining district and the Bodaibo

and Vacha River basins was based on the data gathered by a particularly

large number of field parties. The greater part of the area was not well

known at all, however, and the entire Aldan River basin, the Stanovoi

Mountains, and the area east of the Vitim River were known only from the

reports of occasional travelers. Local areas in the northern, central, and

southern Cis -B b aikal had been thoroughly studied, but only fragmentary inform–

tion was available about the rest of the area, as well as about the western

Khamar-Daban Mountains between the headwatersof the Dzhida River and the

Mongolian border.

        Considerable advanced have been made in the geological study of the area

but these recent studies have not been uniformly intensive and have not

covered the entire region. The southern half of the eastern Trans -B b aikal and

various portions of the western Trans -B b aikal, the Cis -B b aikal, the Lena section,

and the Aldan Plateau have been thoroughly investigated; the other sections

of the region less thoroughly. If one judges by available literature, our

knowled ge of other parts of this vast region has not advanced beyond the

pre-Revolutionary scope of information. Unfortunately the reports of many

field parties have never been published; these probably contain much supple–

mentary material. The fact that publication lags considerably behind field

research limits our knowledge and hampers geologists. This lag, incidentally,

is not peculiar to the area under discussion but applies to all Siberian

geological literature; the delay is worst of all, however, in the case of

the eastern and northeastern areas.

        The various sections are discussed separately, from west to east.

        The Cis -B b aikal has been most thoroughly studied in the valleys of the

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Buguldeika, Anga, and Sarma rivers, in the Lena Valley, and in the vicinity of

Cape Elckhin. The presence of Archean, Proterozoic, and Lower Cambrian forma–

tions has been established here. The Archean rocks have been grouped into

three divisions as have the Proterozoic; the Lower Cambrian formations, on

the other hand, have been divided into two units. The upper Proterozoic

rocks, which have been further grouped into the Colousten, the Uluntuisk, and

the Kachergat series, lie unconformably upon lower and middle Proterozoic

rocks. The g G olousten, Uluntuisk, and Kachergat series are not Cambrian, as

had been thought previously. The Cambrian sequence consists of the Motsk

conglomerates and the Ushakov series; it lies unconformably upon the Proterozoic

rocks. The region’s pre-Cambrian intrusions have been studied. Middle Cambrian

limestones and Upper Cambrian red sediments that merge upward into Ordovician

formations are found in the mountains in the western part of the section.

        An early Quaternary river system that drained westward, rather than into

Lake Baikal, has been discovered; the reversal of drainage, of course, indi–

cates recent downsinking of the lake. Two glaciations have been identified

in the Primorskii Mountains, to the north.

        The Archean and early Proterozoic folds in this section strike ENE.-WSW.,

that is, across the strike of the Lake Baikal structural depression. The folds

of upper Proterozoic age, on the other hand, strike NW-SE., while the Cambrian

folds strike again NE.-SW. and are overturned to the northwest. Geologists

still disagree as to whether the Cambrian folds constitute a marginal zone of

rocks that were squeezed against the Baikal Shield from the direction of the

Siberian Platform (Suess), or whether the Caledonian orogeny also involved the

Proterozoic rocks. The question whether the Archean rocks were thrust over

Jurassic formations in the Angara headwaters region by thrust faulting, or by

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reverse faulting, is also in dispute.

        Pavlovski , Tsvetkov, and, in part, Katnshenok made the most significant

contributions on the geology of the central section of the region, Arsenev

and Maslov on the northern section, and Ge rv vr ussvich, Dumitreshko, and Kolenko

on the southern section.

        The Baikal Upland has not been studied very thoroughly. Investigations

have established Archean rocks and a thick Proterozoic sequence that has

been grouped into several divisions. (These Proterozoic formations border

upon an area of Lower and Middle Cambrian outcrops.) The contact between

Proterozoic and Cambrian rocks has not been exactly determined and is

currently the subject of dispute (Ditmar, Dombrovski ) .

        An area of old mica deposits along the lower course of the Mama River

has been studied thoroughly. Pegmatite dikes out crystalline limestones

and schists in a great syncline in a granite terrain (Markov, Misharev).

Much of the area between the Mama and Angara rivers remains unexplored.

Dumitrashko, however, has made geomorphological studies in the vicinity of

the Angara River. He has also collected new data about the Archean, Quaternary,

and late glacial deposits in the area.

        The Lena gold district has seen a renewal of geological investigation

only recently, be means of field parties sent out by the Nigrizoloto and

Zolotorazvedka Gold Prospecting Agency. The first studies of the presumably

Proterozoic rocks in the valleys of the Bodaibo, upper Vacha, Nygra, and

Kadal rivers have led to a grouping of the rocks into four division. An

unconformity separates the second divisions from the third, and an as yet

unidentified fossil fauna has been found in the lowest division. Two ancient

erosion surfaces and several Quaternary formations have also been identified.

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Geologists tended to deny regional glaciations at first, but new data

indicate that glaciations has occurred. Zolotorazvedka field parties have

identified the morainal deposits of two glaciations of uncertain age in the

northern portions of the Zhuia River basin. Field parties of the Geological

Scientific Research and Development Institute (gold section) have divided

the Middle, and especially the Lower, Cambrian sequence into a number of

units along the lower courses of the Vitim and Bolshoi Patom rivers at the

borders of the Starostin district. Klevenskii, who worked along the Mal y i

Patom and Molvo rivers farther east, proved the existence of a thick Lower

Cambrian sequence; the sequence includes cong l omerates that carry granite and

gneiss fragments. Klevenski has also described a thin sequence of Middle

Cambrian limestones, and a great thickness of Upper Cambrian redbeds. These

findings are confirmed by Areenev’s, along the lower Olekma, farther east,

where the thickness of the Lower Cambrian sequence is 800 meters and that of

the Middle Cambrian sequence 75 meters.

        Gerasimov has described the granites of the peak between the Ugakhan and

Nygra rivers on the basis of old data, and analysed their relation to the local

placer gold deposits. He assigns an early Cambrian date to the granites.

        As regards the tectonics of the area, the latest investigations have

shown that the metamorphic rocks in the southern portion had been subject to

intense and complicated folding and that the Cambrian formations on the eastern

and southern margins are also strongly folded.

        The western Trans -B b aikal has been described quite thoroughly in a great

number of hitherto unpublished reports. This is particularly true of the

Ba t r guzin section. We note, however, the publication of Eskola’s work on the

Sviatoi Nos [ ?] and the upper B o a rguzin River valley; this treatment is

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based upon the Finnish geologist’s pre-Revolutionary observations, and

describes and interprets the Archean of both areas and the Proterozoic

rocks of the Barguzin Valley. Meister, Polovinkina, and Svitalskii have

described the geology of the northern Mui Mountains and the Vitim Plateau;

these geologists, like Eskola, based their treatment upon old data. Carusevich

and Zaklinskaia gathered new data on the geochemistry of the Archean rocks

in the Turka River basin. Pavlovski described the Archean, Proterozoic and

Cambrian tectonics, and the plentiful evidence of glaciations in the central

Vitim Upland. Arsenev investigated the central portions of the Vitim Valley;

he presented data on the tectonics, effects of glaciations, the upper Proterozoic

and Jurassic stratigraphic sequences, the granite intrusions, and the pre–

Cretaceous and Quaternary basalts.

        Shatski has found a high-angle reverse fault that moved pre-Cambrian

over folded Jurassic rocks at the Selenga headwaters; he correlated it with

reverse faulting at the mouth of the Angara River. Tetiaev and Vasilevskii

studied the vicinity of the Pitatelevskii Springs. Tetiaev led a field party

into the neighboring Khamar-Daban and upper Udinsk region, where they mapped

the outcrops and the structure of the metamorphic, late Paleozoic and Mesozoic

formations, and established a post-Jurassic age of most of the granite intrusions.

Florensov and Larin investigated the coal series at Lake Gusin and grouped

the terrigenous strata into Upper Jurassic, Lower Cretaceous, and Tertiary

sequences. The Jurassic folds strike N W E -SW. here and Archean rocks are

thrust over Jurassic in the Monostoi Mountains. Arsenev investigated the

coal-bearing Tertiary series on the southeastern shores of Lake Baikal;

later, Riabukhin studied the sequence in connection with a local oil-prospecting

program. Palibin described the local Tertiary flora.

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        A number of geologists — Garusevich, Korzhenskii, Pilipenko, and

Smirnov — have investigated the Sliudianka P p hlogopite deposits. The

local Archean rocks and the pegmatite dikes that cut them have been

described. Pilipenko found that the effects of glaciation in the Khemar–

Daban Mountains extend almost to the water level of Lake Baikal. Prokopenko

and the Lomakin Brothers crossed this range in its southern portion, between

the Irkut River basin plain and the headwaters of the Dzhida River. They mapped

the outcrops and make-up of the pre-Cambrian and lower Paleozoic sequences,

and noted the fundamental features of the basalts that outcrop on the peaks

of the range.

        In the Dzhida headwaters section, Naletov studies the pre-Cambrian rocks

(one sequence carries algae), archaeocyathid-bearing Cambrian formations, the

Mesozoic coal series, the Quaternary deposits, the Caledonian and Variscan

folds and intrusions, and the younger basalts. Shalsev investigated the

central Dzhida Valley and found the same pre-Cambrian and Cambrian sequences,

in addition to Jurassic terrigenous beds, six igneous intrusions of various

ages, and the tuffs of three volcanic cycles. Vereshchagin had analyzed the

stratigraphy and tectonics of the coal series. Bes e o va has described the

Cambrian tungsten deposits in the Dzhida River. Levitski , Misharin,

Smolianinov, Speit, and others have also described these deposits.

        Farther east, the Balegin iron ore deposits were investigated by

Domrachev and Pavlov, and were found to be sedimentary. Preobrazhenski

and Purtov measured the potential output.

        In the central Khilka River S s ection, Vereshchagin investigated the

metamorphic rocks, the uppermost Paleozoic conglomerate series, the Jurassic

coal series, the Tertiary formations, the intrusive and extrusive rocks,

the younger basalts, and tectonics.

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        Arsenev encountered crystalline and metamorphic pre-Cambrian and lower

Palezoic rocks in the Tsagankhuntei Range, as well as great granitoid bodies

and an upper Paleozoic tuff-lava series that is cut by alkali granites and

syenites. The syenites go over into grudurite and selvsbergite at the

margins. Teschenite loccoliths lift the layers of a Lower Cretaceous coal

series at one locality. Necheeva described the alkaline intrusions.

        Dengin investigated the central Chikoi River basin, and described the

local metamorphic rocks, granites, extrusives, tectonics, and the Gutai

molybdemm deposits. Voskresenskii investigated the gold deposits in the

Chikoi gold district (as did Malyshev and Staln e o v) and studied the morainal

and terraced terrain there. The Cutai mining district was investigated by

Tataev and Fersman, and Donskoi called attention to the fact that the fossil–

bearing local lower Carboniferous sequence rests unconformably upon meta–

morphic rocks.

        The mineal springs and lakes of the western Trans -B b aikal have been

described by Butyrin, Gladtsin, Dengin, Nikolaev, Tolstikhin, Frank-Kementskii,

and others; Soanovskii described the local paleolithic artifacts.

        The Aldan Plateau was known p o nly from the reconnaissance data that

Zverev gathered along the Maia and Aldan rivers, and from the older data

gathered by Middendorf and Meglitski. Recent research, however, has ampli–

fied our knowledge of the region considerably. In the extreme wester n portion

of the region , the Tommot gold mining district was described by Zverev

and later by Bakhvalov. The latter described the Archean basement complex,

and its intrusives, the Lower Cambrian marine sequence, the terrigenous

Jurassic sequence, the subsequent alkaline syenites intrusive and basic dikes,

the Archean folding, and the post-Jurassic faulting and block movements.

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Arsenev divided the Archean sequence along the Olemka River into three units.

Fastalovich and Petrovskii described two types of gold [?] d eposits in the

L a e bedinsk mining district. Korzhenski crossed the plateau as far as the

T y i mpton River. He investigated the petrography of the Archean rocks and

the stratigraphy of the Cambrian and Jurassic sequences, classified the

metamorphic rocks according to depth, and reported several varieties of

cyanite and corundum.

        The gold deposits in Archean rocks between the Aldan and T y i mpton rivers

were described by Serpukhov. Ivanov and Stoliar discovered and described

the Uchurochiulbin gold district. This involved the investigation of the

local Archean complex, the very thick Cambrian sequence with its cong l omerates

and fossil fauna, the basic igneous rocks, and the structure. In the subse–

quently discovered Allakhiun Allakh-Iun gold district, in the northern portion of

the plateau, Bilibin, Baikov, Dzevanovskii, Potebinia, Serpukhov, and others

described the Lower and Middle Cambrian, Ordovician, Silurian, Upper Devonian,

upper Carboniferous, Permian, and Triassic sequences; the various intrusions

and the local tectonic effects of the Caledonian, Variscan, and later orogeny;

the gold deposits and the local effects of glaciations. Postoev noted the

effect of the latest tectonic movements in his geomorphological analysis

of the section. Iakzhin described the plateau’s phlogopit s e deposits.

        The Stanov i o Mountains border the Aldan Plateau on the south. To this

day our knowledge of the regional geology is fragmentary. Obruchev drew

the inference, from new data that the Stanovoi Mountains are entirely separate

and distinct from the Iablonovyi Range. The distinctions are orographic as

well as tectonic. Obruchev described the pre-Cambrian and its intrusion,

as well as the more recent extrusives and tectonics. Anert compiled the

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older materials on the Tuskan and Mulam river headwaters region, and

Korzhenaki i conducted a geological reconnaissance along an Amur-Yakutia

route, mapped the more recent intrusive, extrusives, and the tectonic

structures, and established the boundaries and litho lo gic character of the

pre-Cambrian, Paleozoic, and Jurassic sequences.

        Florov described the Aian gold district; Vasilchenko described the

porphyries, tuffs, and sedimentary rocks of the Ulia River basin; and

Leontovich seven Cambrian formations (one fossil-bearing) in the central

Mai n a Valley, as well as the Cambrian gabbro-diabase dikes and sills, the

Devonian and Mesozoic formations, and the granitoids and porphyries along

the Sea of Okhotsk coast. Alekseichik investigated the stratigraphy,

tectonics, oil possibilities, and oil-shale reserves in the Aim River section.

Pavlovski i extended Obruchev’s idea that the Stanovoi Mountains are the

upper hinge of the young monoclinal flexure that affects the entire Baikal

s S hield as far southwest as the shores of Lake Baikal, and as far south as

the Mongolian border. Pavlovski i also called attention to the large number

of grabens (including the Lake Baikal graben) in the Trans -B b aikal region.

He also studied the times of origin for the grabens and their similarity

to the grabens of Africa, and suggested that the Baikal grabens are downthrown

blocks between twin sets of reverse faults rather than the downdropped blocks

of rifts, that is, they are the products of horst tectonics.

        The eastern Trans -B b aikal was known, at first, only from engineering

reports on the Nerchinsk district; later on during the construction of the

Trnas-Siberian Railroad, Gerasimov and Gedroits made a reconnaissance of the

southern portion of the region, and Voznesonski i and Makerov of the northern,

More recent research has yielded a great deal of new material, some quite

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unexpected largely from the southern section. The northern portion of the

region — the Olekma headwaters and the Ingoda and shilka river valleys —

have been explored much less intensively.

        Proceeding from m s outh to north, the following are the most significant

results of geological exploration in the region.

        Immediately after the Revolution Zver [?] ev, Krektar, Svitlovaki i , and

Smirnov studied and described the Nerchinak silver-lead-zinc deposits.

Artemev further described the lead deposits; Vardaniants, Doktorovich,

Crebnitski i , Sushchinski i , and Tetiaev described the tungsten and precious

stones deposits; and Arsenev and Makerov the local gold deposits. Obruchev

described the Ilinsk and Evgrafovsk gold deposits on the basis of data

gathered in 1912; Savalev described the latter.

        Between 1925 and 1929 a number of field parties under Tetisev investi–

gated the eastern half of the area. These parties studied the fossil fauna,

the marine Devonian sedimentary rocks, the lower Carboniferous sedimentary

rocks (formerly regarded as Devonian), and the Permian, Upper and Lower

Triassic, Lower and Middle Jurassic, terrigenous Lower Cretaceous, and

Tertiary formations. These geologists dated the metamorphic rocks of the

section as Paleozoic (unfossiliferous). They also determined that the

tectonic development began with recurrent thrusting (“ [?] t ectonic lamination”)

to the southeast. These inferences grew out of comparisons to the nappes of

the Alps and western Europe. A reevaluation of regional maps after 1929 showed

that these conclusions were wrong; high-angle reverse faulting rather than

nappe structure dominates the tectonic picture. These investigations also

revealed a smaller area of granite intrusion, the presence of scattered

Ordovician-Silurian outcrops, the possibility of pre-Cambrian outcrops, and

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the presence of complicated large-scale folds that strike N W E .-SW. associated

with a set of north-south folds of Variscan date or at least older than

Upper Jurassic. It is possible that Caledonian folds are present also. A

considerable portion of the granitic rocks is older than Upper Jurassic and

is, in fact, pre-Permian, that is, Variscan age. It has been confirmed

that the local neutral and alkaline extrusives are late Jurassic, and the

basalts are Tertiary and Quaternary. The upper Mesozoic and Tertiary tectonic

movements took the form of upward and downward block faulting that was asso–

ciated with volcanic activity, thrusting, and a gentle folding of Cretaceous

and Tertiary strata.

        These later investigations were carried out by Atlasov, Luchitski i ,

Maksimov, Maslov, Pavlovski i , Rudnev, D. S. Sokolov, Khudiaev, Shchukin, and

others.

        Artemev, Kreiter, Smirnov, and others continued their study of the local

silver, lead, zinc, tungsten, and tin deposits. A new tin district in the

Onon headwaters section has been repeatedly examined and described. Pavlov,

Pilipenko, and Lavrovich described the fluorite and gold deposits along the

Onon and Unda rivers. Various geologists have described the Chernovsk,

Khalbon, and Kharanor coal deposits. The ground water, mineral springs, and

hydrolaccoliths of the region were studied by Gladtsin, Dzens-Litovski i ,

Makorov, Silin-Bekoburin, and Tolstikhin; the salt lakes were investigated

by Pavlov; the fossil fauna by Kichigina, Krymgolts, Nekhorochev, Rukhin, and

Khudiaev; and the fossil flora by Khakhlov. Sheimsan has synthesized the data

on the structure of the eastern Trans -B b aikal, and has correlated it with the

structure of Mongolia.

        Nenadkevich and Khrush o c hev studied the bismuth deposits along the Kara

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and Amazar rivers, in the northern half of the region. Gor oønostaev, Zemel,

Rikhin, Khakhlov, and others investigated the gold-bearing quartz and

tourmaline veins along the Kara River. The Darasunsk gold and polymetallic

deposits were also studied. Eight full reports on the geology of the

Bukachachinsk coal deposits are available. The Ushmunsk tungsten deposits

have also been described in detail. Efremov, Pavlovski i , and Sobolev have

gathered new data in the upper Olekma Valley.

        The Amur Region and the Southern Maritime Provinces (Including Sakhalin) .

Before the Revolution, a small amount of data about those sections of this

region that lie along the Amur and Ussuri railway route was available, and

considerable data about the geology of the gold districts along the Zeia,

Selemdzha, and Amgun rivers. Incomplete data were also available about the

Uda River basin, the Ozornyi (Lake) section, the Sikhote-Alin Ranges, and

Sakhalin Island. The coal deposits of western Sakhalin and the small oil

deposits in the eastern part of the island had been studied.

        Recent development of mining industries and the construction of the

Baikal-Amur Railway trunk line has advanced our knowledge of the geology

of the region immeasurably. The most thorough studies were made in the

Bureia River basin, the Mal y i Khingan Mountains, the southern portion of the

Sikhots-Alin, the southern portion of the Ussuri section, and Sakhalin Island.

In the northern sections of the region, however, the section from Zeia head–

waters to the mouth of the Amur remained virtually neglected. The great

energy with which the Far East Section of the Soviet Geological Survey

carried research forward, in this region, is worthy of attention; since this

organization’s headquarters have been moved from Vladivostok to Khabarovsk

(when the Geological Survey became the Geological Administration), its activities

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in the Far East have tapered off, and the publication of materials on the

region under consideration has ceased.

        The Ka A mur section was subject to intensive geological investigation

because of the presence of gold, schoelite, and antimony deposits along

the Zeia River and in the Tukuringra Mountains. These deposits were studied

by Ar o sentev, Makerov, Popov, Preobrazhenski i , and

others. The tungsten and molybdenum deposits along the Selemdzha-Bureia

divide have been investigated by Artemev, Vitgeft, Volarovich, Golubin,

Mokin, and others. The iron-bearing quartzites of the Mal y i Khingan were

studied by Aleksandrov, Vitgeft, Danilovich, Dubrov, Pavlov, Sokolov, and

Tkalich. Jurassic and Tertiary coal deposits elsewhere in the section have

been examined to a lesser extent. The leading investigators of these deposits

have been Arsentev, Bochkovskaia, Bykov, Davydov, Konstantov, Matvcev,

Ponomarenko, Skorokhod, Kheraskov, and Shatski i .

        Other economic deposits that have been investigated include the Oldoi

River platinums, the Bogucha m n River fluorites, and the Soiuznoe mineral springs,

as well as the effects of glaciation in the Tukuringra Mountains, and permafrost.

The geology of the Jewish Autonomous Province has been investigated (Abdulaev,

Krishtofovich, Bruk, and Shkorbatov), as have been the geology along the

Baikal-Amur trunk line and the region’s soils and swamps. A number of reports

on the petrography of the various sections have appeared (Afanasev, Bolshakov,

Dominikovski i , Lebedev, Polovinkin, Stron, and Suslov). Brauner, Voronets,

Riabinin, and Sokolov have described the fossil faunas of the region, and

Krishtofovich, Maslov, Prinada, and Shtempel the fossil floras.

        These investigators ascertained age, structure, and genesis of previously

known and newly discovered economic deposits, and described the geology of the

region. The greater part of the regional terrain is found to consist of

Archean and Proterozoic rocks; a lesser part of Ordovician, Silurian, Devonian,

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and Lower Jurassic marine sequences, terrigenous Upper Jurassic and Cretaceous

and Tertiary formations. The pre-Cambrian and Paleozoic rocks contain many

intrusives, and the Jurassic sediments have also been invaded by young

granites; the latter are still the center of considerable controversy, however.

The strike and degree of deformation of pre-Cambrian, Paleozoic, and Mesozoic

folding have been clarified. The tectonics of the Malyi Khingan, in par–

ticular, have been clarified. Here the pre-Cambrian folds strike N.-S. and

the Mesozoic folds strike NE.-SW.; the latter, however, are influenced by

the former. Pre-Devonian, pre-Jurassic, Upper Jurassic or Lower Cretaceous,

and pre-Tertiary orogenic cycles have been identified, in addition to the

pre-Cambrian. The Tertiary folding was gentle.

        The Southern Maritime Provinces attracted geologists’ attention because

iron and coal deposits exist in the vicinity of Vladivostok and in the

Sikhote-Alin Mountains. The northern half of the region, along the Amur

and Amgun rivers, and the Ozernyi section between them, has been investigated

less thoroughly.

        A considerable number of geologists have studied the Permian-to-Tertiary

coal deposits in the islands, peninsulas, and coastal areas around Vladivostok,

and along the lower Suchan River. The Suchan coal deposits are found at depth.

The Triassic, Jurassic, Cretaceous, and Tertiary rock sequences here have

been the subject of a great number of studies, both incidental and special;

the age of the rocks, of course, was determined paleontologically. The

Triassic and Jurassic periods were marked by marine transgressions and

volcanism.

        Among the outstanding students of the region are Anert . , Vittenburg,

Elieshevich, Kozlov, A. I. Krishtofovich, Libus, Pavlov, M. Preobrazhenski i ,

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Prinada, Tkalich, and Shtempel.

        To the north, in the Suifun section, Koslov, A. I. Krishtofovich,

Pentegov, Precorazhenski i , and Iavorski i investigated the Jurassic coal

basin and the iron deposits.

        The southern portion of the Sikhote-Alin Mountains contain a number

of exploitable deposits in addition to the Suchan coal field. These include

the magnetite deposits of the Olginsk-Vladimirsk section, Tetiukhe Ppoly–

metallic deposits, and a number of points at which tin can be mined by

open-pit methods. Thus far, gold and oil prospecting has gone forward only

on the reconnssance level. The main stock of data on the area has been

gathered by Volarovich, Gregorev, Dervis, Danilovich, Ivantishin, Kozlov,

A. I. Preobrazhenski, Rusakov, Smirnov, and Skorokhod. Skorokhod and

Volarovich wrote a general report on the area.

        The Khekhtayr Mountains south of Khabarovsk, along the lower Ussuri

River, were first studied by Leontovich, Prinada, and Pek. The Amur River

below Khabarovsk was studied by a field party that was sponsored by the

Soviet Academy of Science s and consisted of Danilovich, Kozlov, and Sokolov.

The field party found marine sediments of Triassic, Jurassic, and early

Cretaceous age, a Tertiary cola series, and both intrusives and extrusives.

Malioranski i explored the northern portion of the Sikhote-Alin between

Lake Kizi and the mouth of the Amur, and found that extrusive rocks dominate

the lithology. Alekseevski i and Polevoi investigated the iron deposits in

the basalt section around Nikol s a evsk, and Preobrazhenski i the gold placer

deposits along the Limura River. Kazanski i first explored the Ozernyi section,

in 1914, but his report did not appear until after the Revolution. Subsequently

Efremov and Pavlovski i studied the area and found great thicknesses of upper

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Paleozoic and Triassic sediments, evidence of recent oscillatory movements,

and extrusive basalts. Arsentev, followed by Preobrazbenski i and Seregin,

investigated the O C hlia-Orel lakes, mount Belaia, and Kol River gold deposits.

Mikhnovich investigated the Komsomolsk section, and found Middle and Upper

Triassic and Lower Cretaceous sediments, and Cretaceous granitoids and young

basalts. Bagurin found tungsten and tin deposits at Lake Udyl and along

the lower Amur.

        The fossil fauna of the region was collected and identified by Vittenburg,

Voronets, Kiparisov, Kokkerel, Kruglov, Krymgolts, Martynov, and Riabinin;

the fossil flora was described by Zalesski i , Krasser, Krishtofovich, Maslov,

Palibin, Prinada, and Shtempel.

        The study of the tectonics of the Sikhote-Alin Mountains has not advanced

very far. Generally speaking, however, the structure seems to be a pair of

major anticlines, the combined width of which exceeds that of the mountain

system. The anticlines strike N [?] E .-SW., and carry large brachyanticlines.

The outcrops on the crests of these anticlines consist of early and late

Paleozoic rocks, while Mesozoic rocks form the limbs. Cretaceous rocks,

deformed less than their predecessors, occupy the s u y nclines and are overlain

by Tertiary rocks that are even less deformed. The tectonic results of several

orogenic movements are superimposed upon one another. The last powerful

disturbance took place in the Kimmerian Kimeridgian orogenic epoch and was accompanied

by granite intrusion. The molding of the geanticline was completed in the

Austrian epoch when high-angle reverse faulting and volcanic activity began

which continued for some time. The great thrust from the southeast postulated

by Tetiaev and a number of his colleagues does not exist.

        Sakhalin Island was rather well known geologically before the Revolution,

046      |      Vol_I-0521                                                                                                                  
EA-I. Obruchev: Geology of Russia Siberia

but more detailed studies of the island have been made since that time

especially in the coal and oil regions. An intensive study of well sections,

cross sections and paleontological data led to a detailed knowledge of the

marine, terrigeonous, and extrusive Cretaceous and Tertiary rocks that make

up most of Sakhalin. The coals and geology of the western shore have been

studied by Vitgeft, Volkovich, Gapeev, I latov, Krishtofovich, Polevoi, and

the Japanese geologists Yabe and Shimitsu. The petroleum deposits of the

western shore were investigated by Bunin, Krish ot to fovich, and Shcherbakov,

and the main pools, on the eastern shore by Abazov, Gedroits, Damperov,

Kobziashi, Kosygin, Mironov, Perfilev, Polevol, Tanasevich, Khomenko, and

others. The two interior mountain chains, which include Paleozoic rocks

and contain gold deposits, have been studied by Vitgeft, Eliscev, Krishtofovich,

and Khomenko; Smekhov, Khmolev, Khomenko, and Shakhov investigated the geology

of the Schmidt Peninsula.

        The fossil fauna of the island was investigated by Argomakov, Voloshinov,

Gayaseka, Nagao, Chernyshev, Khomenko, and Isbe, and the fossils flora by

Krishtofovich and Poiakrov. Krishtofovich, Polevoi, Sokolov, and Tikhonovich

wrote a general treatment of the geology of the island.

        According to Pleshakov’s recent study, Sakhalin Island is made up of

folded geosynclinals sediments of late Cretaceous and Tertiary age. Six

stages of the Alpine orogeny are discernable; the Kamchatkan disturbance,

between the Upper Cretaceous and the Tertiary; the Kurilean disturbance,

between the Oligocene and Miocene; the Amurian disturbance, between the

middle and late Miocene; the Tatarian disturbance, in the upper Pliocene;

and the Okhotsk disturbance, in Pleistocene time. The island has been sinking

since the latter half of the Pleistocene time. The folds are overturned to

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both east and west, and are associated with faults and thrusts.

        The Northeastern Region includes the upper Verkh o i nsk ansk -Kolyma section,

the Chukotsk-Anadyr section, and the Kamchatka P eninsula. This was the

least known portion of Siberia. The only available data about the region

consisted of the reports of occasional travelers; some of these were very

old. After the Revolution the Northern Sea Route Administration whose ships —

the region’s only source of supplies — round these coasts, undertook geo–

logical investigations. The discovery of precious metals, coal, and petroleum

started a study of the entire area.

        The Soviet Academy expeditions to Kamchatka and the founding of the

Volcanological Station there laid the foundations for the systematic study

of the only part of the Soviet Union where active volcanoes exist. Unfor–

tunately, the reports of the field parties that worked under the auspices

of the Kamchatka Trust, and the Daletroi (q.v.) organization that succeeded

it, have never been published.

        The Upper Iana Verkhoiansk -Kolyma section include s the great vast Iana, Kolyme, and Indigirka

river basins. Before the Revolution parts of the region had been visited by

reconnaissance parties under Wrangel, Toll, Volosovich, Maidel, Tolmachev,

and Cherski i . Vast areas, however, remained unknown.

        All of the mountain ranges which separate the river basins have been

studied since, and these investigations resulted in the discovery, by a party

under S. V. Obruchev, of a great mountain system between the Indigirka and

Kolyma river basins. This system, which was named the Cherski i Mountains

after the geologist who first crossed it at a point at which its extent and

elevation cannot be seen, consists of several ranges of rugged relief which

shelter small mountain glaciers. The basins of the section’s most important

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EA-I. Obruchev: Geology of Russia Siberia

rivers were studied, as were several less important upland areas along the

arctic littoral, and several river divides along the Okhotsk littoral to

the south.

        A considerable number of geologists have investigated the Verkhoiansk

Mountains recently. A. A. Grigorev laid the groundwork for these investiga–

tions when he crossed these mountains in their central portion. Thereafter

geologists turned their attention to the old silver- and lead-mining districts

in these mountains, and to the Orulgan and Kharsulakh Mountains farther north,

In the latest phase of the study of the area, geologists have ventured into

the mountains to the south of Grigorev’s route. The northwestern portion of

the area has been found to consist of a uniform series of Permian, Triassic,

and Jurassic sandstones. (One member of the local Permian sequence carries a

fossil flora.) Cambrian, Ordovician, Silurian, Devonian, and Carboniferous

formations outcrop beneath the Permian in the Kharaulakh Range; Lower Cretaceous

marine and terrigeonous Tertiary sequences overlie the Permian. Pre-Cambrian,

Cambrian, Ordovician, Silurian, Permian, and Triassic strata, and intrusives,

little represented in the northwest, outcrop in the southeastern part of the

region. On the whole, erosion has not reached the Mesozoic rocks in the

northwest.

        Tectonically, the Kharaulakh Range consists of folds that have been

overturned and thrust to the west. Late Mesozoic tectonic movements have

masked the results of Caledonian and Variscan orogenics. The reasons for

the arcuate shape of the range are not yet understood.

        The quite recent discovery of tin along the Adycha River has attracted

geologists to the great basin of the Iana River; geological investigations

have not progressed very far, however. The metals are genetically connected

049      |      Vol_I-0524                                                                                                                  
EA-I. Obruchev: Geology of Russia Siberia

with Cretaceous granites that have out lower Permian, Upper Triassic, and

Jurassic sediments.

        Little is known about the Tas-Khaiakhtakh Mountains, with their Cambrian,

Ordovician, Silurian, Devonian, upper Paleozoic, Triassic, and Jurassic marine

formations; its Tertiary and Quaternary sequences; and its periods of igneous

activity (the last igneous rocks were emplaced in Cretaceous times).

        The relationships between the Cherski i Mountains and the Tas-Khaiakhtakh

are not clear as yet. The former system consists of nine or ten high ranges.

Though Paleozoic rocks outcrop at some points, Triassic and Jurassic forma–

tions cut by granites dominate the lithology of the mountain system. At

some points the Mesozoic sequence also includes Lower and Upper Cretaceous

terrigeonous formations. Folds that were thrown up in a Mesozoic synclinorium

that formed after the folding of the sediments in Paleozoic times constitute

the tectonic structure of the mountain system. These Mesozoic folds are

overturned to the north and south. Among the igneous rocks post-Silurian

granites and diorites, Upper Jurassic and Lower Cretaceous granites, and

Jurassic extrusives are found. Two quite granite intrusions brought

in rich deposits of gold and tin.

        The Kolyma-Iukagir Platform, northeast of the Cherski i Mountains, served

as a central massif around which the Mesozoic geosynclines formed, and against

which the folds of the Mesozoic sediments were braced. The Platform itself,

however, was subject to fairly strong tectonic deformation. Pre-Cambrian,

Cambrian, Ordovician, Silurian, Devonian, and lower Carboniferous formations

are encountered; they seem to be geosynclinal deposits and are strongly deformed.

In passing from the Cherski i Mountains to the Kolyma-Iukagir Platform, one

notices that the Triassic formations lose thickness and turn red. The Jurassic

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EA-I. Obruchev: Geology of Russia Siberia

sequence includes lavas, tuffs, and coal beds. The Mesozoic formations are

folded. Young liparites and teschenites are encountered.

        The Kolyma-Okhotsk Divide, which was formerly considered to be a continu–

ation of the Stanovoi Mountains, has been found in its eastern portion to

consist of terrigeonous upper Permian formations, three divisions of a marine

Triassic sequence, Jurassic formations, and a Cretaceous sequence rich in

extrusives. Again, in the Okhota, Gusinka, Ulbei, and Kukhtui river valleys,

to the west, Triassic-to - Cretaceous formations are found to be accompanied by extru–

sions and granite intrusions. Tertiary sediments and extrusive liparites and

marekanites are found along the Okhotsk coast.

        The chain of coastal plateaus that includes such ranges as the Sviatoi

Nos, the Alazeia, the Polous, and the Aniui is incompletely known. At central

points in these plateaus, Cambrian, Ordovician, Silurian, Carboniferous, and

Permian formations occur, but Triassic, Jurassic, Lower Cretaceous and, to a

lesser extent, Tertiary formations dominate the regional picture. The

products of volcanic activity that ended in Quaternary time (chiefly basalts)

are widespread. The strike of the folds appears to follow that of the folds

of the Kolyma Platform.

        Only Bolshoi Liakhovski i Island, in the Novo-Sibirski i Archipelago, has

been studied with any considerable thoroughness recently; we must depend upon

old data for our knowledge of the rest of the archipelago. A Cambrian sequence

is known from Bennett Island, and the Kotelyni Island contains sedimentary

formations of Ordovician, Silurian, Devonian, Carboniferous, Triassic, Jurassic,

Tertiary, and Quaternary age, as well as Jurassic granites and Tertiary basalts.

Tectonically, the island in the southern portion of the archipelago belongs to

the Verkhoiansk folded complex. The Paleozoic strata on Bennett Island are

051      |      Vol_I-0526                                                                                                                  
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not disturbed, and this had led some geologists to postulate a Great Arctic

Shield which, for the most part, is now submerged.

        Recent investigations in this area have brought to light much information

on continental glaciations (two or three stages), stream sculpture and pene–

planation, permafrost, ground-ice volume, firnification, and soil geology.

Several geologists have already written general treatises of the section.

Twenty-two investigators have studied the fossil fauna, and four the fossil

flora.

        Geologists who have participated in the study of the region in spite of

handicaps are Atlasov, Vak e a r, the Gusevs, Ermolaev, Lazurkin, Nikolaev,

S. Obruchev, Saks, Smirnov, Fedortsev, and Kheraskev. Kupletski i made the

petrographic analysis of specimens collected by various workers.

        The Chukotka-Anadyr section constitutes the eastern third of arctic

Siberia. It had been poorly investigated before the Revolution. The discovery

of placer-gold deposits in Alaska at the turn of the century occasioned the

exploration of the coast of the Bering Sea by the Bogdanovich expedition.

R L ater the Polevoi expedition penetrated to the central portion of the Anadyr

River basin. The investigation of the region made great advances recently;

even so, we do not know the geology of the entire area yet. The latest data

seem to indicate that the section has three orographic divisions: ( 1 ) the

Chukotka Range in its northern portion; ( 2 ) the Anadyr Plateau in its central

portion; and ( 3 ) the Gydan and Anadyr ranges (a continuation of the O [?] khotsk–

Koly nma Divide) in its southern portion. The Anadyr Depression and its minor

mountain ranges, and the Korisk Mountains to the south, are a continuation of

the Kamchatka Upland.

        In the Chukotka Range there is a belt of pre-Cambrian marbles and crystalline

052      |      Vol_I-0527                                                                                                                  
EA-I. Obruchev: Geology of Russia Siberia

rocks that extends from Koliuchinski Bay to the Bering Strait. In addition,

geologists have found fossil-bearing Silurian, Devonian, and Carboniferous

marine sediments, Permian phyllites, an upper Triassic sequence, and Jurassic

coal-bearing and lava-tuff sequences. The pre-Cambrian and Paleozoic rocks

strike WNW.-ESE., and are intensely deformed and intruded. The most important

tectonic feature of the range, however, is a set of folds of Kimeridgian

(Jurassic) date that also strikes WNW.-ESE. Post Jurassic gabbros, mepheline

syenite, granites, and acid extrusives enter into the composition of the Dezhnev

Range.

        The Anadyr Plateaus is made up of Cenozoic lavas and tuffs. Evidence of

Quaternary volcanism is present.

        The Gydan Range is the divide between the Omolon River (a tributary of

the Kolyma) and the Gizhiga. The country rock is pre-Cambrian and Paleozoic.

Intruded metamorphic rocks of Proterozoic-Paleozoic age (counterparts of the

basement-complex rocks in Alaska) outcrop in these mountains as well as on

the coasts of the Bering Strait; in the latter area, however, these rocks

are covered by extrusives. The lithology of the Anadyr Range, on the other

hand, is dominated by Jurassic, Cretaceous, and Tertiary marine formation,

intruded by a variety of acid and alkaline igneous bodies which were emplaced

by the various regional cycles of tectonic movement and igneous activity.

These injections of magma occurred in Kimeridgian, Austrian, Laramide, and

Oligocene time, and later. The same Mesozoic and Cenozoic sedimentary and

igneous sequences are found in the minor ranges of the Anadyr Basin.

        The Korlak Mountains are, in the main, made up of sandstones, siliceous

shales, in part tuffaceous, and great thicknesses of Tertiary sandstone.

These sediments were folded in a Tertiary-Quaternary transitional orogeny.

Their structure is complicated by normal and reverse faulting, and their

strike is NE.-SW. Later tectonic movements have occurred in the area. Coal

deposits of Cretaceous and Tertiary age are found at the eastern end of the

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mountain system; gabbro, gabbrodiorite, and pyroxenites intrusive are wide–

spread in the area, as are porphyritic and a n desitic extrusives.

        The geology of Wrangel Island was virtually unknown until quite recently.

Lately, however, the island was studied in connection with the work of a

Soviet Academy expedition which was sent out to collect mammoth remains. The

report of this expedition has not been published yet, but it is known that the

island is made up of upper Carboniferous and Upper Triassic rocks, the latter

of marine origin.

        A number of workers have investigated past glaciations of the region, and

their effect upon the development of the terrace and permafrost. Data about

mineral springs and the peat deposits of the Anadyr tundra has also been

gathered. Geologists have collected a few fossil faunas and floras.

        Soviet geologists who have gathered most of the information about the

section are Artemev, Ditmar, Eliseev, Kudriavtsev, Nikolaevski i , S. Obruchev,

Riabkin, and Tikhomirov.

        The Kamchatka Peninsula is the only portion of the Asiatic mainland that

possesses active volcanoes. It is, therefore, natural that it should have

attracted geologists, Russians as well as others, for a considerable number

of years. The systematic geological investigation of the peninsula, however,

was undertaken only in connection with the post-Revolutionary coal and oil

prospecting program, at which time the study of the peninsula’s main volcanoes

also became systematic rather than haphazard. Consequently, the main features

of the geology of Kamchatka are now thoroughly known.

        The Sredinny i (Central) Mountain Range constitutes the axis of the peninsula.

The outcrops along the crest of the rang consist of gneisses, micaschists,

thick phyllites, and Paleozoic argillaceous sandstones. The slopes consist

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of early and middle Mesozoic graywackes and shales (the Volcanic Series),

and Tertiary and Quaternary formations. Periodotites, pyro z x enites, and

some monzonites, outcrop between the sediments. The Paleozoic rocks are

intensely deformed; their folds strike almost north-south. The Mesozoic

rocks are less deformed and are less deformed and are cut by the necks of

extinct Tertiary volcanoes.

        East of the longitudinal valley of the Kamchatka River (also under

systematic study) stand the peninsula’s eastern coastal mountains. Green

tuffaceous shales, the Bogachevka sandstone, four divisions of a Tertiary

sequence, dunites, pyro z x enites, and young extrusives comprise the dominant

rock types.

        A broad belt of the western coastal plane is made up of five divisions

of a Tertiary sequence, the age of which ranges up to Pliocene. Those

sediments contain marine fossils and are covered by Quaternary sediments

and basalt flows. These lie upon a surface eroded upon metamorphic Paleozoic

rocks in the Sredinnyi Range, and upon Cenomanian and Turonian formations in

the Tigil area and at Cape Onman.

        At Korf Gulf, in the extreme north, Mesozoic coal-bearing sediments

and extrusives are encountered. The coal and petroleum deposits of both

coasts have been studied repeatedly.

        A great deal of attention has been paid to the study of the peninsula’s

volcanoes, particularly Mounts Kliuchevski i and Avacha. Mount Kluichevskii

has been under constant systematic study since 1938. Through investigations

have also been under constant systematic study since 1938. Thorough investi–

gations have also been made of the mineral springs, permafrost, past glaciations,

peat bogs, and soils. Paleontologists have studied the dominantly Cenozoic

fossil fauna and flora.

055      |      Vol_I-0530                                                                                                                  
EA-I. Obruchev: Geology in of Siberia

        The Kamchatka area was a geosyncline up until lower Carboniferous time;

then the sediments were thrown into folds which had a NNE.-SSW. strike.

These folds were eroded in Cretaceous times and the sea covered them again.

The present peninsula is the product of a series of tectonic movements,

which occurred between the Cretaceous and Quaternary periods, and which were

accompanied by igneous injection and extrusion along fault planes. The

earlier Quaternary lavas are basaltic and andesitic-basaltic; the later

Quaternary lavas are amphibolites-biotite-andesite.

        Among the geologists who have studied the peninsula are Grechish, Dvali,

Diakov, Lazarenko, Morozov, Polevoi, and Shcherbakov. Vlodavets, Zavaritski i ,

Ivanov, Meniailov, and Novograblenov have played leading roles in volcanological

studies. Z e a varitski i , Krishtofovich, Tebenkov, Kharkhovich, and S h cherbekov

wrote general geological reports of the area.

        In conclusion, we draw attention to the fact that, from time to time,

general accounts of the geology of all of Siberia have been compiled from

accumulated regional studies, just as general regional studies are based on

a synthesis of detailed local studies .

056      |      Vol_I-0531                                                                                                                  
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---

BIBLIOGRAPHY

1. Arkhangelskii, A.D. Geologicheskoe Stroenie i Geologicheskaia Istoria SSSR.

(The Geological Structure and the Geological History of the U.S.S.R.)

Moscow, Leningrad, 1941. Vol.1.

2. -----, and Shatski, N.S. Kratkii Ocherk Geologicheskoi Struktury i Geologi–

cheskoi Istorii SSSR. (Brief Outline of the Geological Structure

and the Geological History of the U.S.S.R.) Moscow, 1937.

3. Borisisk, A.A. Geologicheskii Ocherk Sibiri. (Geological Sketch of Siberia.)

Petrograd, 1923.

4. Edelshtein, I.S. “Geologicheskii ocherk Zapadno-Sibirskoi ravniny.”

(Geological sketch of the Wst Siberian plain.) Gosudarstvennce Russkoe

Geograficheskoe Obshchestvo, Zapadno-Sibirski Otdel, Omsk, Izvestiia

vol.5, 1925/ 1 2 6.

5. Iavorski, V.I., and Butov, P.I. “Kuznetskii Kamennougolnyi Bassein.”

(The Kuznetsk coal basin.) Russia. Geologicheski Komitet, St. Petersburg.

Trudy n.s., vol.177, 1927.

6. Mazarovich, A.N. Osnovy Geologii SSSR . (The Basic Elements of the Geology

of the U.S.S.R.) Moscow, 1938.

7. Nekhoroshev, V.P. Geherki po Geologii Sibiri . (Essays on the Geology of

Siberia.) Moscow, 1932.

8. Obruchev, S.V. Novaia Orograficheskaia Skhe n m a Severo-Vostochnoi Azii.

(New Orographic Outline of Northeastern Asia.) Leningrad, 1940.

9. ----. Ocherk Tektoniki Severo-Vostochnoi Azii . (Outline of the Techtonicas

of North-Eastern Asia.) Leningrad, 1938.

10. Obruchev, V.A. Geologia Sibiri . (Geology of Siberia.) Leningrad, Akademiia

Nauk, 1935-38. Vol.I: Dokembrii i Drevnii Paleozoi. (Pre-Cambrian

and Lower Paleozoic.) Vol.II: Srednii i Verkhnii Paleozoi. (Middle and

Upper Paleozoic.) Vol.III: Mezozoi i Kainozoi. (Mesozoic and

Cenozoic.)

11. ----. Geologicheskii Obzor Sibiri . (Geological Review of Siberia.) Moscow,

Goe.Izdat., 1927.

12. ----. Geologie von Sibirien . Berlin, Borntraeger, 1926. Fortschritte

der Geologie und Paleontologie . H.15.

13. ----. Istoriia Geologicheskogo Issledovaniia Sibir . (History of the

Geological Exploration of Siberia.) Moscow, Leningrad, Akedemiia

Nauk, 1931-47. Vol.I-V. (Still being published.)

       

V. A. Obruchev