Carboniferous carbonate rocks of the Chukotka fold belt: Tectonostratigraphy, depositional environments and paleogeography

Accepted Manuscript Title: Carboniferous carbonate rocks of the Chukotka fold belt: Tectnostratigraphy, depositional environments and paleogeography Authors: M.I. Tuchkova, S.D. Sokolov, T.N. Isakova, O.L. Kossovaya, T.V. Filimonova, V.E. Verzhbitsky, O.L Petrov, E.V. Vatrushkina, A.V. Moiseev PII: DOI: Reference:

S0264-3707(17)30179-5 https://doi.org/10.1016/j.jog.2018.05.006 GEOD 1572

To appear in:

Journal of Geodynamics

Received date: Revised date: Accepted date:

12-8-2017 14-3-2018 16-5-2018

Please cite this article as: Tuchkova, M.I., Sokolov, S.D., Isakova, T.N., Kossovaya, O.L., Filimonova, T.V., Verzhbitsky, V.E., Petrov, O.L, Vatrushkina, E.V., Moiseev, A.V., Carboniferous carbonate rocks of the Chukotka fold belt: Tectnostratigraphy, depositional environments and paleogeography.Journal of Geodynamics https://doi.org/10.1016/j.jog.2018.05.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Comments/corrections 19.04.2018/MT

Carboniferous

carbonate

rocks

of

the

Chukotka

fold

belt:

Tectnostratigraphy, depositional environments and paleogeography

Verzhbitsky V.E.3, Petrov O.L.1, Vatrushkina E.V.1, Moiseev A.V.1

IP T

Tuchkova M.I.1*, Sokolov S.D.1, Isakova T.N.1, Kossovaya O.L.2, Filimonova T.V.1,

Geological Institute, Russian Academy of Science, Pyzhevsky pereulok 7, Moscow, Russia

2

Federal State Budgetary Institution “A.P. Karpinsky Russian Geological Research Institute”,

SC R

1

Srednii prospect, 74, St-Petersburg, Russia 3

Shirshov Institute of Oceanology, Russian Academy of Science, Nakhimovski prospect, 36,

N

U

Moscow, Russia

* Corresponding author

M

A

*e-mail: [email protected], [email protected]

ED

Abstract

PT

New faunal data from Carboniferous carbonates on Wrangel Island and Chukotka Peninsula (within Kuul, Alyarmaut and Polyarnyui Uplifts) are used to identify stratigraphic sequences and for regional correlations. The facies and geochemical data indicate that Carboniferous sediments

CC E

on Wrangel Island, Kibera Cape and the Alyarmaut Uplift were deposited on a carbonate platform that was part of the passive continental margin of Arctida (the Hyperborean platform). Limestone of the Polyarnyui Uplift was formed on an isolated seamount in the oceanic basin.

A

The geochemical and isotopic characteristics of rocks on Wrangel Island and in the Kuul and in the Alyarmaut Uplifts show the alternation of limestone formed in marine environments and limestone with the characteristics of a freshwater basin. Limestones of the Polyarnyui Uplift formed in a seamount of oceanic marine environment. A new paleogeographic model is proposed based on faunal, isotopic and geochemical characteristics of limestone. In the Early Carboniferous, carbonate platform were located in Chukotka and in the Wrangel Island. In the Late Carboniferous, the area of carbonate sedimentation was reduced and deposits accumulated

in a shallower setting in Wrangel Island and in Kuul Uplift. Correlation of the Carboniferous sequences, sedimentary environments and geochemical composition of limestones on the carbonate platform showed three stages of tectonic activity: i) the boundary between the Visean and Serpukhovian Stages corresponds to regional uplift of the carbonate platform and termination of carbonate sedimentation in the oceanic basin; Tectonic reorganization within the ii) Bashkirian Stage and at the iii) beginning of the Early Permian is expressed only in the

IP T

sequences of the Wrangel Island.

Keywords: Wrangel Island, Chukotka, Carboniferous, carbonates, oxygen (δ13O) and carbon

SC R

(δ18C) isotopes, REE, paleogeography

1. Introduction

Characteristics of the Paleozoic carbonate deposits of Chukotka are known mainly from the results of the geological survey carried out in the 1950s-1970 (Yegorov and Afitskii, 1957;

U

Yegorov, 1962; Sadovskii et al., 1962; Aksyonova, 1966; Sadovskii and Gel'man, 1970).

N

Paleozoic carbonate rocks of the Wrangel Island were studied in the 1950s-1970s- and later

A

(Geology of the USSR 1947, 1970; Lobanov, 1957; Til’man et al., 1964; Byalobzheskii and Ivanov, 1971; Ivanov, 1973; Vasil'eva et al., 1974; Kameneva, 1975, 1977; Kameneva and

M

Chernyak, 1975; Kos’ko et al., 1993, 2003). Based on these studies several editions of paleogeographic maps were produced (Vinogradov et al., 1969; Tkachenko, B.V., Yegiazarov

ED

B.Kh., 1970, 1970; Ustritskii, 1975; Lavwer et al., 2011; Golonka, 2011 and etc). However, paleoreconstructions for the Carboniferous were created only for some areas of the Arctic and

PT

their correlation is often difficult (Bogdanov, Til'man, 1964; Rogozov et al., 1968, 1970; Sizykh

CC E

et al., 1977; Embry, 1993; Kos'ko et al., 2003, 2013).

In the Paleozoic, the Asian region of the eastern Arctic is believed to have been a realm of shelf sedimentation located in close proximity to a continental block that was a source of abundant terrigenous material (Bogdanov, Til'man, 1964, 1992). This continental block is referred to as the

A

Hyperborean platform (Shatskii, 1935; Bogdanov and Til'man, 1964), Arctida (Eardly, 1948; Zonenshain et al., 1990; Vernikovsky and Vernikovskaya, 2001; Vernikovsky et al., 2011) or Crocker Land (Embry, 1993, 2009).

According to Parftenov (1984), Paleozoic deposits of Chukotka are a part of the miogeosyncline zone of the Brooks-Wrangel fold belt and represent the basement of the Chukotka fold belt. All

carbonates were assumed to belong to similar tectonic structures composed of Paleozoic deposits (Gorodinskii, 1963; Parfenov, 1984; Tibilov and Cherepanova, 2001).

In Chukotka, Paleozoic deposits are confined to young uplifts bounded by faults. These uplifts belong to different tectonic structures of the Chukotka fold belt (Fedorovsky and Shilo, 1980; Parfenov, 1984; Tibilov and Cherepanova, 2001; Sokolov et al., 2010) (Fig. 1). The uplifts have nearly longitudinal (Polyarnyui and Alyarmaut) and latitudinal (Kuul, Kuekvun’ and Wrangel

IP T

Island) orientations (Fig. 2).

The detailed structures of these uplifts are complicated and are characterized by numerous

SC R

thrusts and fault slices. Sedimentary rocks are part of these thrust-and-fold structures. As a result, correlation of Paleozoic carbonate deposits of different uplifts is difficult and requires the use of geochemical and isotopic methods along with stratigraphic ones. According to Webb et al. (2000), Tanaka et al. (2003) and Letnikova (2005) geochemical and isotopic techniques can

U

provide reliable data on the genesis of tectonically disturbed and metamorphosed carbonate

A

N

complexes.

This paper presents correlations based on comprehensive studies of Carboniferous carbonate

M

rocks of Chukotka and Wrangel Island and addresses the following problems: (a) Whether spatially separated outcrops of carbonate rocks belong to the northern continental block (the

ED

Hyperborean platform) or not; (b) It is possible to consider if the carbonate of the Polyarnyui Uplift were genetically not related to carbonate of the continental block, as was previously

PT

suggested by Sokolov et al. (2006). Geochemistry, oxygen (δ13O) and carbon (δ18C) isotope composition of Carboniferous deposits of eastern Chukotka were studied for the first time.

CC E

Materail were collected during field work on Wrangel Island (Novosibirsk-Wrangel Fold Belt) in 2006 and 2014, in Anyui-Chukotka Fold Belt- from 2003 to 2010, and in the South-Anyui Fold belt in 2000. Based on new faunal findings and revision of previous studies, the age of Paleozoic deposits is clarified andcorrelation of sequences is suggested. A new paleogeographic model of

A

sedimentation is proposed for the Carboniferous, and the geodynamic setting of Carboniferous deposits is discussed in the context of eastern Arctic tectonic and paleogeographic history.

2. Methods Petrographic investigations included determinations of carbonate composition, quantity and composition of impurities, and presence or absence of organic detritus. Carbonate rocks are

classified after Pettijohn (1975). Composition of carbonates and terrigenous impurities were also studied using powder X-ray diffraction at the Lithology Department of Gubkin Russian State University of Oil and Gas (National Research University) (analyst - D.I. Kudryavtsev). Contents of trace elements in the samples were measured on a Thermo Scientific ICP mass spectrometer at the Institute of Microelectronics Technology and High-Purity Materials (Chernogolovka, Russia). The techniques of sample preparation and analysis are described by Karandashev et al. (2007). Natural rock samples were subjected to acid digestion in an open

IP T

system. The accuracy of measurements was evaluated by analysis of standard samples, which were prepared together with our samples. The contents of elements in the specimens were

SC R

determined using standard solutions based on the multielemental ICP-MS-68 standard.

Oxygen (δ13O) and carbon (δ18C) isotope compositions were analyzed using devices of the Thermo Electron Corporation, including a Delta V Advantage mass spectrometer and GasBench-II, at the Geological Institute of the Russian Academy of Sciences (GIN RAS, Moscow,

U

Russia) (analysts – O.L.Petrov and B.G. Pokrovskii). Samples and standards (KH-2 and NBS-

N

19) were digested in Н3РО4 at a temperature of 50oC. Contents of 13С and 18О are given in

A

mille (‰) relative to V-PDB and V-SMOW standards, respectively.

M

Microfaunas consist of foraminifers and conodonts. The first were identified in thin-sections of carbonate rocks by T.N. Isakova and T.V. Filimonova (GIN RAS, Moscow, Russia).

ED

Conodonts were separated from samples using the technique of Ivanov (1987) and identified by A.A. Aristov and N.V.Goreva (GIN RAS, Moscow, Russia). We did not determine CAI (color

PT

alteration index) of conodonts for this paper. Macrofaunas consist of corals studied by O.L. Kossovaya (A.P. Karpinsky Russian Geological Research Institute, VSEGEI, St. Petersburg,

CC E

Russia).

3. General geological setting The rocks described in this paper belong to the Chukotka fold belt and the New Siberian-

A

Wrangel and Anyui-Chukotka fold belts and South Anyui Fold Belt (South Anyui suture zone) (Parfenov et al., 1993; Kos’ko et al., 1993; Khanchick, 2006; Sokolov, 2010) which are composed of a number of terranes and subterranes (Fig. 1). The Wrangel Island and the Wrangel terrane are a part of the New Siberian-Wrangel fold belt (Til’man et al., 1964; Kameneva, 1975, 1977; Kos’ko et al., 1993). The Wrangel Island is divided into three tectonic zones referred to as the Northern, Central and Southern zones (Fig.4), each of which has distinctive stratigraphic, lithologic and structural features (Sokolov et al.,

2017). The fold-and-thrust structure of the Wrangel Island has northern vergence which resulted from near-longitudinal compression. In addition, in the Northern zone the Upper Silurian-Middle Devonian deposits are folds of sub-latitudinal compression (Verzhbitsky, 2014, 2015). In the Central zone, the deformed Neoproterozoic and Devonian-Carboniferous rocks with northern vergence are inconformably overlain by the undeformed carbonates of the Lower and Upper Carboniferous (Sokolov et al., 2017).

IP T

On the Wrangel Island, most rocks of the Central zone are thrust over those of the Northern zone in the north, and are overthrust by rocks of the Southern zone in the south (Sokolov et al., 2017).

SC R

Carbonate rocks of Krasnyi Flag River area (Central Tectonic zone), they are not folded.

The Kuul Uplift and the Alyarmaut Uplift are a part of the Anyui-Chukotka fold belt: The Kuul Uplift belongs to the Chaun subterrane; the Alyarmaut Uplift – to the Anyui subterrane. (Fig. 1). Ellesmerian deformation of the Kuul Uplift is overprinted by younger structures expressed as

U

northern-northeastern thrusts (Katkov, 2014). Paleozoic and Mesozoic complexes of the

N

Alyarmaut Uplift also have thrust structures with northwestern vergence that originated in the

A

latest Neocomian. In the Aptian-Albian, extension and normal faulting were dominant and accompanied by formation of a metamorphic dome and exhumation of Paleozoic metamorphic

M

rocks (Sokolov et al., 2001; Luchitskaya et al., 2010). The block of carbonate rocks of the Polyarnyui Uplift belongs to the South Anyui suture zone that separates the Chukotka and

ED

Verkhoyansk-Kolyma folded areas. The Polyarnyui Uplift also exhibits fold-and-thrust structures, with Carboniferous strata in the lower plate; these structures are complicated by

PT

younger, post-collisional deformations (Bondarenko, 2004; Sokolov, 2010; Sokolov et al., 2015).

CC E

On the Wrangel Island, Paleozoic rocks are characterized by initial stages of greenshist metamorphism (Kosko, 2003). In the other uplifts, the metamorphic grade generally does not exceed the greenshist stage. However in several outcrops of the Alyarmaut Uplift, rock near the Lyupveem granitoid batholith experienced contact metamorphism was observed. Therefore

A

samples from these units haven't been used for geochemical and isotope analyses. Original faunal and lithologic features are mostly well preserved in the rocks examined for this study.

4. Tectonostratigraphic units (1) The Wrangel terrane, Wrangel Island. Distinct Carboniferous sequences are found in the Central and Southern zones and are here considered separately. The stratigraphic units (D3-C1, C2-P and etc.) are given in accordance with those shown in the geological map of Wrangel

Island (after Kos'ko et al., 2003, Fig. 4). In Fig. 3, the numbers of the described Units and Subunits are indicated; for convenience, this numbering is also presented in the text.

(1-1) The Central tectonic zone. Studied sequences of this type are located in the basins of the Neizvestnaya, Mamontovaya and Krasnyi Flag rivers (Figs. 2 – 5). Carbonate deposits are divided into three units. They consist of: (1-1a) the upper part of the sequence in the DevonianLower Carboniferous unit ((D3-C1), (1-1b) the "lower" Carboniferous and (1-1c) the "upper"

IP T

Carboniferous units. The contact with overlying deposits is tectonic; in some places there is a stratigraphic unconformity.

SC R

(1-1a) Limestone composes the upper part of the Devonian-Lower Carboniferous tectonostratigraphic unit (Fig. 3, 5). The carbonate sequence lies on the argillite member in the Krasnyi Flag River area, and is represented by sub-unit 1.

U

Sub-unit 1. Grey and dark grey limestone interbedded with black lime mudstone. Carbonate

N

consists of wackestone and lime mudstone in beds up to 1.5-2 meters thick with lenses of black

A

nodular chert. Sandy limestone makes up a few beds as well. Rocks are cleaved (Fig. 7) and multiply folded.

M

Previously, the presence of corals (Dibunophyllum turbinatum (McCoy), Canadiphyllum ex gr. knoxi Sutherland, Corwenia ex gr. rugosa (McCoy), Caninia juddiformis Gorsky, Lithostrotion

ED

acolumellata Dobroljubova) and brachiopods (Gigantoproductus sp., Plicatifera aff. plicatilis (Sowerby), Brachythyris cf. gracilis (Phillips)) was interpreted to indicate a Namurian age

PT

(SerpukhovianStage, Reitlinger, 1975) for the rocks that include these faunas (Chernyak and

CC E

Kameneva, 1976).

More recently, this limestone was dated asVisean and Tournaisian-Visean (Kos’ko, 2003). Limestone samples collected in 2006 by the authors contain conodonts (Taphrognathus aff. varians Branson and Mehl) which indicate a Visean age for this sub-unit (sample 06/58,

A

coordinates N 71o14.644; W 179o18.926).

Black and dark grey wackestone and sandy and silty limestone occure in this sub-unit. The latter rocks are characterized by local cross-lamination and rarer convolute lamination and slump folds. Cross bedding measurements indicate a northeastward transport direction. Limestone contains beds and lenses of grey chert (Fig. 5). The limestone is composed of calcite and

dolomite and contains minor quartz grains (size 0.05-0.1mm) in some thin-sections. All samples have micro-lenses and micro-beds of silica.

The lime mudstone is made of calcite with minor dolomite. It is commonly silicified and includes relicts of undeterminable and recrystallized faunas in some samples. Rocks bear disseminated organic matter locally replaced by spherical aggregates and large crystals of pyrite

IP T

(0.01-0.1 mm in size).

Interpretation: Shallow-water shelf deposits near organic buildups (reefs or bioherms). Increasing numbers of carbonate beds from the south to the north in the northeastern area and the

SC R

clastic material transport direction indicate that sources of the terrigenous material were located to the southwest of the Krasnyi Flag River (between the upper reaches of Neizvestnaya, Khishchnikov and Mamontovaya Rivers).

U

(1-1b) The "lower" Carboniferous Unit is composed of two sub-units: limestone with chert (sub-

N

unit 2) and “evaporite” (sub-unit 3) in the sequence of Krasnyi Flag River (Fig. 5). The unit is

A

provisionally attributed to the Lower Carboniferous based on its location within the Central zone, the style of deformation and the similarity with Lower Carboniferous gypsum-bearing

M

deposits elsewhere on the Wrangel Island (Sokolov et al., 2017). The rocks display cleavage and are slightly deformed; beds dip at angles of 30-40о. A direct contact with the underlying deposits

ED

wasn't observed, but we believe that the "lower" Carboniferous Unit discordantly rests on older

PT

strata.

Sub-unit 2. Limestone with chert. Grainstone (calcarenite) and lime and chert mudstone of the

CC E

"lower" unit are grey to dark grey colored rocks with lenses and beds of chert and a few beds of sandy limestone. Sandy limestone is characterized by graded bedding. Calcarenite is composed of sparite and microsparite made up of slightly rounded fragments of limestone and indeterminate faunal remnants, with a few crystals of dolomite, gypsum, Mg-calcite and

A

aragonite present in some samples. Debris is 0.2-1.5 mm in size; cement aggregates are no larger than 0.01 mm (Fig. 7). Sandy limestone is represented by fine grained lithic arenite with quartz and granitoid rock fragments. More common lime mudstone is composed of microsparite with dolomite grains and rare lenses and beds of grey and dark-grey chert.

Interpretation: Sediments formed in a local depression in the inner ramp near a bioherm.

Sub-unit 3. "Evaporite" member (gypsum-bearing limestones). This member is made of interbedded wackestone, packstone and gypsum-bearing rocks; grainstone is rare. The “evaporite" has an unusual bright white color that distinguishes this rock type. The thickness of "evaporite" beds increases upward within the sequence and reaches about 14 cm. Wackestone and packstone are represented by calcilutite with micrite cement and slightly rounded limestone fragments and faunal remnants: debris is 0.2-1.5 mm in size (Fig. 7). Lenticular organic matter aligned parallel to the cleavage direction occurs rarely. Evaporite beds are composed of calcite,

IP T

dolomite, and ≤15-20% gypsum and contain slightly rounded fragments of limestone and macrofaunal debris. Debris is 0.2-1.2 mm in size. In addition dust minerals (size of aggregate < 0.001 mm, ultra-fine clay? or other minerals) are observed in all samples of this unit, therefore

SC R

some geochemical ratios are very high.

Interpretation: Inner ramp lagoon with ramp barrier bar. The presence of thin evaporate beds in

A

N

of the shelf, culminating in formation of a lagoon.

U

the lower part of the sequence that increase in thickness upward, indicates increasing restriction

(1-1c) Rocks of this unit are slightly deformed, contain conglomerate at the base (sub-unit 4) and

M

rest upon Proterozoic rocks with a sharp angular unconformity (the Neizvestnaya River section, Fig. 5). Limestone with abundant fossils (sub-unit 5) overlies the basal conglomerate. In the

PT

consists of limestone.

ED

Krasnyi Flag River sequence, basal conglomerate is absent, and the "upper" Carboniferous Unit

Sub-unit 4. Basal conglomerate is composed of clasts that range from 3-5 to 12-17 cm in size.

CC E

Clast types include basalt, limestone, various types of schist, granite and quartz in a matrix of gravel- to coarse sand-sized grains. The clast composition gradually changes upward: basalt debris (more than 80 %) prevails at the base and quartz debris (from 15 to 50%) occurs in the upper part of the subunit. Individual beds are 0.3-0.5 m thick. In the upper part of sub-unit 4,

A

quartz-bearing gravel and coarse-grained sandstone accumulated. Some quartz grains are coated by a film of ferrugous material and orange ochre.

Interpretation: Shallow-water marine deposits close to eroded intrashelf uplifts. Intensive erosion of uplifted areas resulted in deposition of conglomerate and gravel composed of pebbles of basalt, granite, schist and limestone. Extended exposure of these uplifts is indicated by the

presence of ochre material and ferrugenous rims on some clasts, suggesting erosion and redeposition of weathering crusts.

Sub-unit 5. Limestone: clastic, bioclastic and biogenic varieties. Limestone in this sub-unit contains abundant and diverse fossils (brachiopods, foraminifers, goniatites, bryozoans, corals, crinoids and numerous types of algae). The fauna indicates that the age of this subunit is Bashkirian and Moscovian in age (Chernyak and Kameneva, 1976; Ganelin et al., 1989; Kos'ko

IP T

et al., 2003, Figs. 3, 8).

At the base of a section of limestone alternating with sandy limestone beds, Chernyak and

SC R

Kameneva (1976) found numerous brachiopods (Schizophoria resupinata (Martin), Juresania juresanensis (Tschernyschew), Jakutella sarytchevae Abramov, Echinoconchus cf. fasciatus (Kutorga), Krotovia cf. tuberculata (Moeller), Neospirifer aff. triplicates (Hall), Brachythyrina cf. strangwaysi (Verneuil)), rare goniatids (Stenopronorites uralensis (Karpinsky). Schartymites

U

sp., Verneuilites sp.), and Bashkirian-Moscovian foraminifers (Endothyra cf. bradyi Mikhailov,

N

Eostaffella cf. pseudostruvei chomatifera Kireeva, Novella pulchra Potievskaya, Pseudostaffella

A

ex gr. subquadrata Grozdilova et Lebedeva, Ozawainella eoangulata Manukalova,

M

Profusulinella sp., Schubertella sp., Globivalvulina granulosa Reitlinger).

In the upper part of the limestone sequence at the same location, foraminifera of the Moscovian

ED

Stage such as Pseudostaffella ex gr. ozawai (Dutkevich), P. ex. gr. pseudosubquadrata Manukalova, Profusulinella aff. chernovi Rauser, P. ex. gr. Simplex Safonova, Schubertella aff.

PT

obscura Lee et Chen., were found (Chernyak and Kameneva, 1976).

CC E

New data on conodonts, foraminifers and corals from the "upper" Carboniferous Unit were obtained for this paper. Limestone overlying Proterozoic rocks of the Neizvestnaya River contains conodonts (Declinognathodus marginodosus (Grayson)) indicative of a Bashkirian Moscovian age (collection made in 2006, sample coordinates N 71o15.339; W 179o15.566).

A

Fasciculate colonial corals (Parahetschioides sp.) were found in the River Krasnyi Flag section (collection made in 2014). In the eastern Arctic (Alaska), this species is characteristic of a Bashkirian –Moscovian age (Fedorowski and Stevens, 2014).

The limestone of sub-unit 5 also contains foraminifers (Eowaeringella ex gr. Lata (Thompson), Eowaeringella aff. castigata Solovieva, Eowaeringella aff. pseudomatura (Ross et Tyrrell), Eowaeringella sp., Kanmeraia aff. pseudozelleri Solovieva, Kanmeraia sp., Pseudoendothyra

sp.) which suggest a wider age range in age from Late Moscovian - Early Kasimovian (2014 collection, Figs. 3, 9, 10). Also, debris of the coral Siphonodendron inopinatum (Gorsky) of Late Visean - Early Serpukhovian age (2014 collection, sample 706/7, coordinates N71o15.764; W 178o48.475) was found along with the foraminiferal fauna of the Bashkirian-Moscovian Stages in the sequence of the Krasnyi Flag River. This suggests the redeposition of Lower Carboniferous fossils into younger beds. In addition to foraminifers, algae (?Ungdarella sp., Komia sp., sample 701/1, coordinates N 71o18.208; W 178o50.739) were found in sub-unit 5

IP T

strata.

Sub-unit 5 contains light grey, dark grey, and very dark, almost black limestone. All limestone of

SC R

sub-unit contains abundant variably preserved fossils (corals, crinoids, bryozoans, foraminifera etc.). Faunal debris is often replaced by silica. Limestone is represented by wackestone, packstone, grainstone, redeposited limestone and lime mudstone. Wackestone exhibits lamination expressed as a thin intercalation of sparite and micrite; some sparite beds contain

U

fossils and quartz grains. Grainstone is represented by calcarenite and is mainly composed of

N

calcite (0.05-0.1 in size); Mg-calcite (0.5-1.8 mm in size) is also locally present. Lime mudstone

A

is made of recrystallized sparite and micrite. Redeposited limestone consists of rhythmic beds, 10-12 cm thick, that are graded at the base. They contain redeposited fossil debris (including

M

algae and bryozoans) and limestone clasts and are interpreted as turbidites or storm deposits.

ED

Interpretation: Inner ramp and mid-ramp near an uplift composed of weathered metamorphic rocks and Lower Carboniferous limestone. Sediments deposited in shallow-water and reworked

PT

in surf- and wind-influenced zones. Thin turbidities or storm deposits were derived

CC E

from erosion of this uplift.

(1-2) The Southern tectonic zone. This sequence was investigated in the basins of the Khishchnikov and Somnitel'naya rivers, on V'uchnyi Creek, and at the Uering and Ptichii Bazar Capes. Carboniferous carbonate rocks constitute two tectonostratigraphic units (Fig. 3, 6): (1-2a)

A

the Devonian - Lower Carboniferous (D3-C1) and (1-2b) the Upper Carboniferous (C2) or the Upper Carboniferous - Permian (according to Kos'ko et al., 2003). In contrast to the Central zone, all units show fold-and-thrust structures.

(1-2a) Carbonate composes the upper part of the sequence of the D3-C1 unit (Khishchnikov River and Ptichii Bazar Cape) and consists of 5 sub-units.

Sub-unit 1. Conglomerate, gravel and coarse sandstone. At the base of the Carboniferous sequence, Upper Devonian clay mudstone and siltstone are overlain by beds and lenses of conglomerate and gravel intercalated with coarse-grained sandstone (Fig. 6). The thickness of the conglomerate beds is 0.1-0.3 m. Rock clasts in conglomerate are 0.5-0.7 cm in size. The clasts consist of sedimentary rocks, quartz, and quartzite as well as carbonate, schist, granite and basic volcanic rocks (Fig. 7). Sandstone associated with coarse-grained rocks is lithic arenite

IP T

with sparite, gypsum, and Mg-calcite cement.

Interpretation: Inner ramp. A shallow-water marine setting, with periodic reworking of sedimentary material by surf and storms. Conglomerate composed the front of a coarse-grained

SC R

transgressive delta.

Sub-unit 2. Carbonate with chert. Conglomerate is overlain by sandy limestone, grainstone, and lime mudstone, commonly with lenses and beds of chert (Khishchnikov River). The limestone

U

contains a fauna of Tournaisian-Visean age, including brachiopods, conodonts and corals

A

N

(Chernyak and Kameneva, 1976; Ganelin et al., 1989; Kos'ko et al., 2003).

Coeval carbonate rocks in the upper reaches of the Khishchnikov River that are assigned to

M

subunit 2 consist of thinly interbedded pink-grey lime-dolostone and dolostone containing the Visean corals Amplexus coralloides (Sowerby), Dibunophyllum aff. derbience Sibly,

ED

Clisiophyllum aff. reticullatum (Gorsky), Gangamophyllum sp., Corwenia aff. regularis Gorsky,

PT

and Corwenia aff. socialis Gorsky (Ganelin et al., 1989; Kos'ko et al., 2003).

CC E

Interpretation: Local depression near an uplift on shelf.

Sub-unit 3. Wackestone and calcareous shale. Limestone in this sub-unit contains the Serpukhovian foraminifers Pseudoendothyra aff. ovalis Vdovenko, Archaediscus itineraries Schlykova, A. krestovnikovi koktjubensis Rauser and Planoarchaediscus spirillinoides (Rauser)

A

as well as very rare brachiopods (Meekella cf. thomasi Jan.) (Chernyak and Kameneva, 1976).

Wackestones are dark grey and nearly black rocks with lenses and beds of black or grey chert. Rocks are massive or show graded bedding. At the base of some beds there are horizons with redeposited faunas. Rocks contain from 10 to 30 % quartz grains that are 0.05-0.2 mm in size. Rocks are composed of calcite, Mg-calcite, and dolomite grains 0.1-0.2 mm in size (Fig.7).

Fine-grained rocks consist of lime mudstone and silty mudstone. Mudstone is composed of micrite and cleaved; silty mudstone, despite intensive cleavage, preserves cross bedding.

Interpretation: Inner ramp and mid-ramp. A shallow-water marine setting, a prodelta in a surf zone.

In the Uering Cape area, the Tournaisian-Serpukhovian member of the sequence is represented

IP T

by carbonate with variably colored (grey, black, brown and pink, the Uering Formation, Ganelin et al., 1989). Limestone often contains poorly preserved fragments of small Syringoporidae crinoids, remnants of algal thalli, and fragments of bryozoans and spiriferid shells, among them

SC R

Palaechoristites cf.subgrandis (Rotav.) (Ganelin et al., 1989). In addition to limestone, there are beds and lenses of dolomite (Fig. 6). Rocks of the formation are silicified, and biohermal limestone is replaced by secondary dolomite (Ganelin et al., 1989; Kos'ko et al., 2003). Relicts of a primary organogenic texture are widely preserved. Dolomitic limestone contains impurities of

U

rare quartz grains and rock debris. Calcite grains are 0.1-0.2 mm in size; dolomite grains are 0.1-

A

N

0.3 mm in size. Dolomite grains are commonly overgrown by a ferrous rim.

in a setting of algal plains.

M

Interpretation: A biohermal setting characterized by destruction of buildups by periodiccurrents

ED

Sub-unit 4. "Evaporite" (gypsum-bearing limestones). Carbonate of this member is grey and light grey, with beds of reddish grey limestone or reddish dolomite (Figs. 6 and 7). Some bedding

PT

planes show traces of desiccation cracks; others contain fragments of limestone (limestone breccia), that we interpret as evidence of coeval carbonate redeposition. Calcarenite includes up

CC E

to 15-30 % quartz grains 0.05-0.1 mm in size. Cement is composed of sparite and microsparite, with some crystals of dolomite. Samples of evaporite beds contain gypsum, Mgcalcite and aragonite in different proportions: gypsum from 10 to 15%, Mg-calcite 40-65%, aragonite no more than 25%. Grain size of minerals in these beds is 0.05-0.15 mm. Framboidal pyrite or

A

individual crystals of pyrite are typical of all rocks in this sub-unit.

Interpretation: A setting in an isolated part of a basin (or a lagoon) characterized by periodic drying and flooding of coastal areas in a tidal flat. In wetter periods, fragmental carbonate was reworked and redeposited.

Sub-unit 5. In the Ptichii Bazar Cape and Gusinaya River areas, rocks coeval with those described above in unit 1-2a consist of intercalated grainstone, chert and chert limestone, sandy limestone and lime mudstone. The upper part of the sequence contains bioturbation and vertical worm trails (Fig. 6, sample 492/22). In addition, dessication cracks are observed on the surface of some beds of sandstones (Fig. 6, sample 610/1). In the section on the left bank of the Gusinaya River, the Visean-Serpukhovian brachiopods Derbia carteri Cooper et Grunt, Tubaria rectaurita Sar., Reticularia ivanovi (Lap.), R. uralica (Tschern.), Kutorginella novosemliensis

IP T

Kal., Chaoiella bathycolops (Schellw), Pleurohorridonia carbonaria Kalasch., Marginiferra sp., Sajakella martianovi (Lap.), Flucturia neoundata Miron., Linoproductus coralineatus Nikitin, L. cf.tenuiliratus Step., Purdonella praenikitini Kalaschn., Composita sp., and Ambocoelia

SC R

sp.,(cited after Kos'ko et al., 2003, p. 39).

Interpretation: A lagoon characterized by periodic exposure in the upper part of the

U

sequence.

N

(1-2b) The Carboniferous (C2) or Upper Carboniferous-Permian (C2-P) (according to Kos'ko et

A

al., 2003) Unit is recognized in the basins of the Khishchnikov and Somnitel'naya rivers, the V'uchnyi watershed, and in the vicinities of the Ptichii Bazar and Uering Capes. Partial sections

M

from different outcrops are combined in sub-unit 6; the overall sequence is based on faunal

ED

evidence.

Sub-unit 6. The sequence is composed of grey or dark grey grainstone, rudstone and boundstone

PT

intercalated with grey and brown dolomitic limestone and sandy limestone with subordinate beds of lime mudstones (Fig. 6). On the left bank of the Khishchnikov River, thin beds of limestone

CC E

(5-12 cm thick) in this part of the sequence exhibit cross laminae and convolute laminae. A few measurements of crossbedding show flow direction is to the east.

We correlated partial sections of sub-unit 6 using sedimentological data. Also, faunal data were

A

used - both published data and new findings. Conodonts found in limestone in sub-unit 6 are Idiognathoides marginodosus (Grayson) in the Ptichii Bazar Cape section and Idiognathoides cf. marginodosus in the upper reaches of the Khishchnikov River; they indicate an age corresponding to the Early-Middle Moscovian Stage (Kos'ko et al., 2003). A Bashkirian age for part of sub-unit 6 is confirmed by Bashkirian foraminifers in some sections of the Southern zone, described by (Chernyak and Kameneva, 1976). Foraminifers are Eostaffella aff. pseudostruvei Raus. et Bel., Endothyranella aff. donbassica Reitl., Millerella elegantula Raus., Archaediscus

aff. magnus Schlykova., Neoarchaediscus aff. collatatus Sossipatrova, Tetrataxis aff. digna Grozdilova. et Lebedeva, Ozawainella sp., Tetrataxis eominima Lee et Chen (Chernyak and Kameneva, 1976). New data on corals and foraminifers from the Somnitel’naya River area and the V'uchnyi watershed were obtained by the authors in 2014; fossils from the upper reaches of the Somnitel'naya River indicate a Bashkirian or younger age. New fossils from V’uchnyi watershed

IP T

consist of the corals Bothroclisia aff. clisiophylloides Fomichev (sample 732/2), Multitecopora sokolovi Vas. (sample 732/2, coordinates N 71o02.043;W179o41.963), and Caninella koscharowi (Stuck.) (Samples 735а and 735/2, coordinates N71o01.418; W179o40.843) and the

SC R

foraminifer Lateenoglobivalvulina spiralis (Morozova) (sample 732/2) and suggest a BashkirianMoscovian, and perhaps Kasimovian age (Figs. 9, 10). Sample 612/6 (Khishchnikov River area, coordinates

N71o04.145;

W179o12.843)

contains

poorly

preserved

conodont

"Streptognathodus" cf. expansus Igo et Koike, that is characteristic of the upper part of the

U

Bashkirian Stage (determined by N.V. Goreva, GIN RAS, Moscow, Russia).

N

Grainstone with abundant faunal remnants (debris of corals, bryozoans, crinoids and

A

foraminifers) contains up to 10 % limestone clasts and quartz grains (size 0.05-0.2 mm); there are also lenses of siliceous material. Both bioclasts and limestone debris are partly rounded and

M

locally replaced by siliceous material. In addition to calcite, rhombic dolomite and gypsum

ED

aggregates occur; Mg-calcite and anhydrite are rare.

Interpretation: Sedimentation in this part of the sequence took place in a dissected submerged

PT

shelf near a large coral reef. At the base of the section, clastic flow deposits transported eroded

CC E

reef fragments onto an algal plain. Bedforms indicate a gentle shelf slope.

(2) The Kuul Uplift. The Kibera Cape. Carbonate rocks of the Kuul Uplift (the Kibera Cape, Pegtymel and Kus'veem rivers) belong to the Chaun subterrane of the Chukotka terrane of the Anyui-Chukotka fold belt (Figs. 1 and 2). Carbonate is exposed in coastal cliffs and belongs to

A

two formations: (2a) the Yunona Formation of the Devonian-Lower Carboniferous (TournaisianSerpukhovian Stages) and (2b) the Kibera Formation (Bashkirian-Moscovian Stages) (Gorodinskii, 1959; Rogozov et al., 1968; 1970; Solovieva, 1975; Tibilov and Cherepanova, 2001, figs. 3 and 6). Deposits are variable in facies and have been folded and thrust-faulted. The overlying Permian-Triassic deposits rest on the Carboniferous deposits without visible angular unconformity. Tibilov and Cherepanova (2001) suggest a stratigraphic contact exists between deposits of the Kibera Formation and Permian-Triassic strata.

(2a) The Yunona Formation is represented by lime mudstone and limestone. Gravel and sandstone with subordinate conglomerate at the base of the section unconformably overlap different horizons of the Devonian. Corals and brachiopods (Amplexus sp., Dibunophyllum sp., Dictyoclostus sp., Rotaja subtrigona? (Meek et Worthen)) in limestone beds intercalated with coarse-grained rocks indicate an age of Tournaisian through Serpukhovian (Rogozov et al.,

IP T

1970; Tibilov and Cherepanova, 2001).

The thickness of gravel and sandstone beds, with minor beds and lenses of conglomerate, varies from 2-3 cm to 0.3-0.5 m (Fig. 11). Conglomerate is polymictic and oligomictic, and clast size

SC R

increases upward within the sequence. Rogozov and Vasil'eva (1970) noted that the size of pebbles in conglomerate of the formation increases from the southeast (Kus'veem Creek) to the northwest (Kibera Cape). Polymictic conglomerate is composed of rounded and slightly rounded pebbles of quartz and granite as well as clay mudstone, sandy limestone and gneiss. Oligomictic

U

conglomerate contains clasts of either granite or schist, clasts are rounded. Both types of

A

N

conglomerates are cemented by calcite or dolomite-calcite.

Sub-unit 1. This subunit consists of conglomerate and gravel beds intercalated with lime

M

mudstone and grainstone, and with sandy limestone in the upper part of the Formation. Lime mudstone locally contains microlenses of siliceous material. Grainstone is represented by

ED

calcarenite rich in clasts (up to 15-20 %) of quartz, limestone, feldspar and granite with a calcite matrix (Fig. 14). Sandy limestone (or quartzite with calcite cement) contains poorly rounded and

PT

rounded sand-sized clasts of quartz, limestone, feldspar, granitoid, and schist. Orientation of pebbles in conglomerate beds show significant currents derived from the north or northeast.

CC E

Grain size of pebbles increases in the upper part of the section, and reverse grading is noted. Upper horizons of this sub-unit include beds dominated by quartz clasts.

Interpretation: The presence of beds and lenses of coarse-grained rocks bearing debris of

A

oligomictic composition indicates input from temporary streams that originated in and eroded adjacent local land masses. The increase of clast size upward within the sequence suggests continuous growth of the uplifted land mass and its intensive erosion during the Serpukhovian Stage. It is assumed that coarse-grained rocks were deposited in a near coastal marine setting close to a rapidly growing and eroded uplift (or uplifts) composed of granite, schist and limestone. The presence of non-rounded feldspar debris in limestone indicates rapid burial of sediments without much transportation of clastic material. Quartz sandstone that overlies the

coarse-grained deposits suggests erosion of the weathering rind of granites on the adjacent landmasses.

Sub-unit 2. The upper part of the Yunona Formation is represented by lime mudstone, sandy and silty limestone and limestone. Limestone in the basin of the Kus'veem River (Umkuvaamkai Creek) and along Yunona Creek includes beds with the foraminifers PseudoendotyraArchaediscus? cornuspiroides and Eosigmoilina explicata – Eostaffellina paraprotvae of the

IP T

Serpukhovian Stage (Solovieva, 1975).

In the basin of the Kus'veem River (Umkuvaamkai Creek) beds with Pseudoendothyra-

SC R

Archaediscus? (= Betpakodiscus) сornuspiroides were studied. Foraminifera are represented by 18 genera. These include different species of Pseudoendothyra (Pseudoendothyra concinna (Schlykova), Ps. aff. probata (Durkina), Ps. aff. umbonata (Rauser), Ps. cf. propinqua (Vissarionova), Ps. struvei (Moeller), Ps. kyrtajolis (Durkina), Ps. luminosa (Ganelina), Ps.

U

ornata (Brady), Ps. aff. kremenskensis Rosovskaya) and species characteristic of the

N

Serpukhovian Stage (Endostaffella parva (Moeller), Loeblichia minima Brazhnikova,

A

Planoarchaediscus absimilis Sossipatrova, Neoarchaediscus sp. and others) (Solovieva, 1975).

M

Stratigraphically higher beds in limestone of the Yunona Creek basin contain Eosigmoilina explicata - Eostaffellina paraprotvae of the Serpukhovian Stage. Seventeen genera of

ED

foraminifers are found in these beds, including the first appearance of the Serpukhovian zonal marker Eostaffellina paraprotvae. and other typical Serpukhovian species such as Eostaffella

CC E

1975).

PT

umbilicata (Kireeva), E. mirifica typica Brazhnikova, Loeblichia sp. and others (Solovieva,

Sub-unit 2 is dominated by calcarenite with abundant clastic material (about 50 %). Clasts 0.2-0.4 mm in size consist of quartz, feldspar, schist, and chert as well as granitoid and micrite

A

limestone.

Interpretation: The accumulation of marine carbonate with abundant fossils indicates a shallow-water shelf setting. Siltstone beds and significant admixture of clastic material in limestone suggest a nearby landmass or an erosion of shelf uplifts.

(2b) The Kibera Formation is composed of biogenic limestone (Rogozov et al., 1970). The Formation occurs locally in the vicinity of Kibera Cape and in the Keveem-Pegtymel' interfluve.

Thickness varies in individual outcrops from 15 to 150 m. The lower part of the Formation contains Bashkirian corals and brachiopods (Neospirifer sp. indet., Amplexus sp., Dibunophyllum sp., Dictyoclostus sp., Rotaja subtrigona? (Meek et Worthen), Choristites ex. gr.bisulcatiformis Semich.), as well as Bashkirian foraminifera (Rogozov et al., 1970; Vasil'eva et al., 1974; Samorukov and Matveenko, 1984). The upper part of the sequence is dominated by limestone and is dated by foraminifers.

IP T

Beds with foraminifera are accepted as an auxiliary biostratigraphic unit, and their finding of the sequence indicates Bashkirian-Moscovian age (Solovieva, 1975; Rogozov et al., 1968; Tibilov and Cherepanova, 2001). Bashkirian foraminifers that were identified include Planoarchaediscus

SC R

stilus – Eostaffella pseudostruvei and Eolasiodiscus donbassicus – Ozawainella. BashkirianMoscovian foraminifers that were identified include Profusulinella – Pseudostafella, including the lowest appearance of the genera Shubertella, Profusulinella and Fusiella, all of which are

U

characteristic of the Moscovian Stage (Solovieva, 1975).

N

In general the Kibera Formation consists of a rhythmic alternation of grey- and dark-colored

A

biogenic limestone with sandy beds of grainstone, wackestone, sandy limestone and lime mudstone. Grainstone in the lower part of the Formation is mainly calcarenite with debris of

M

granitoid and schist; debris of limestone, chert, quartz and feldspar is found in some samples. Wackestone is composed of micrite with minor dolomite and ankerite and contains clasts of

ED

limestone, schist and granitoid. Lime mudstone is rare; it is composed of micrite and

PT

microsparite; microlenses of chert are found in some samples (Fig. 14).

Grainstone in the upper part of the Formation is associated with reddish green dolomitizied

CC E

limestone and biosparite. The grainstone is calcarenite rich in non-rounded or slightly rounded fossils including algal fragments. Limestone in this part of the sequence contains chert beds that are 15-25 cm thick. Chert microlenses occur in some samples of calcarenite and biosparite.

A

Interpretation: A shelf margin characterized by periodic input of clastic debris onto an algal plain. Redeposited material was mainly terrigenous in the lower part of the sequence and synsedimentary limestone in the upper part.

(3) The Alyarmaut Uplift. Basins of the Pogynden and Lyupveem rivers, and the Prokhladnyi and Yagelnyi creeks. Paleozoic sedimentary complexes of the Anyui subterrane of the AnyuiChukotka fold belt together with Mesozoic deposits form a thrust structure with western

vergence that was created during the Neocomian. Rocks are metamorphosed and deformed; they constitute a united Upper Devonian-Lower Carboniferous (D3-C1) complex and can be divided into two Formations of different ages made up of schist/shales and carbonate. Relationships between the formations as well as those with overlying deposits aren't clear in all locations. Divergent interpretations of stratigraphic relationships have been published (Yegorov and Afitskii, 1957; Yegorov, 1962; Sosunov and Til’man, 1960; Sadovskii, Syrkin and Teplykh, 1962; Aksyonova, 1966; Sadovskii and Gel'man, 1970; Bondarenko, Luchitskaya, 2003; Katkov

IP T

et al., 2010). Some authors suggest that the shales overlie the limestones (Sadovskii et al., 1962), and other authors suggest- that the limestones overlie the shales (Yegorov and Afitskii, 1957; Yegorov, 1962). In this study, we assume that the base of the Paleozoic section is the Lyupveem

SC R

Formation (schist/shale) of Late Devonian-Early Carboniferous (D3-C1) age, which is overlain by the carbonate Vernitakaiveem Formation of Early Carboniferous age (C1) (Figs. 3, 9). In some outcrops on the Lyupveem River, the contact between the Lyupveem formation (D3-C1) and the overlying light grey limestone of the Lower Carboniferous (C1) is tectonic (Katkov et

N

U

al., 2010).

A

Corals (Lonsdaleia cf. floriformis Mart., L. cf. longiseptata Gorsky, Favosites sp., Fletcheria sp. indet., Syringopora sp., Zaphrentis sp.indet.) and brachiopods (Spirifer sp. indet.) occur in

M

limestone of the Vernitakaiveem carbonate complex shown in the R-58-XXIX-XXX geological map and indicate aTournaisian-Visean age for these rocks (Sadovskii and Gel'man, 1970;

ED

determinations of G.A. Andianovskaya and A.F. Efimova). The occurrence of Lonsdaleia cf. floriformis Mart. and Lonsdaleia floriformis septentrionalis Gorsky at a locality 6,1 km to the

PT

west suggests the same age for these deposits (Belik, Sosunov, 1969). Unfortunately, the faunal data is very old and it is difficult to link the listed fauna to the units. Based on the stratigraphical

CC E

age of the fauna, we showed its location in the unit presumably (Fig. 12). During field work in 2004, fragments of the colonial coral Siphonodendron irregulare Phillips were found (Figs. 3, 12, sample 04JT20, coordinates N68o54’29.1; E165o55’41.6), indicating a Late Visean age for

A

strata at this site.

In all locations, sections of the Vernitakaiveem complex change upwards from black to white limestone (from sub-unit 1 to sub-unit 4).

Sub-unit 1. The lower part of the formation overlying schist/shale of the Lyupveem Formation is metamorphosed and deformed black metalimestone/limestone with local siltstone beds. The black color of the limestone results from high contents of bituminous organic matter (Fig. 14).

Limestone is composed of sparite containing micro-lenses of siliceous material, rare gypsum crystals and organic matter along the cleavage.

Sub-unit 2. Black metalimestone of sub-unit 1 grades up into intercalated black and grey beds (wackestone and grainstone). Most beds are calcarenite composed of sparite and slightly rounded schist debris, with local gravel-sized grains of quartz. This sub-unit also contains beds of quartz

IP T

sandstone.

Sub-unit 3. Intercalated grey and white limestone beds containing lenses and beds of chert comprise this sub-unit. Microlenses of siliceous material occur in calcarenite composed of

SC R

sparite and rarer microsparite; no terrigenous admixture occurs in these beds.

Sub-unit 4. At the top of the sequence, marble with beds of quartz sandstone occurs. The marble is free of terrigenous impurities and is composed of sparite and microsparite; single grains of

N

U

Mg-calcite can be present. Quartzite consists of sand-sized quartz grains cemented by calcite.

A

Interpretation: Rare single colonies of corals and brachiopods, lack of other macrofauna indicate the deep shelf environment. Perhaps the lower part of the sequence made up of dark

M

metalimestone was deposited on a shelf margin at the beginning of a transgression. A voluminous supply of nutrients from the nearest landmass resulted in an active growth of

ED

microfauna followed by its mass extinction. This explains why dark-colored limestone is replaced by light-colored rocks upward in the sequence. A low supply of terrigenous material

PT

from land and gradual development of a carbonate platform created conditions for light grey and white limestone deposition. Carbonate at the top of the sequence formed in a shallow-water

CC E

setting. A periodic supply of reworked material (possibly the weathering rind of a metamorphic complex) produced beds of quartz sandstone.

(4) The Polyarnyui Uplift. The Polyarnyui Creek. Carbonate rocks of the Polyarnyui Uplift are

A

included in the South Anyui suture zone (Figs. 1 and 2). Rocks of the uplift constitute the Lower Carboniferous Polyarnyui complex, which is divided into two units (Sizykh et al., 1977; Sokolov, 2010; Sokolov et al., 2015). The lower unit is basalt, chert and carbonate and the upper unit is composed of subvolcanic rocks of intermediate and felsic composition with blocks and boulders of limestone (Fig. 13). Corals (Faberophyllum sp., Turbophyllum sp. and Caninophyllum sp. indet.) found in limestone boulders (Fig. 3) indicate a Visean age (determination of Yu.P. Onoprienko, cited after Sizykh et al., 1977). Relations of limestone with

the volcanic rocks are disputed. According to (Bondarenko, 2004) the contact is stratigraphic. In contrast, Lychagin (1997) noted clasts of volcanic rocks in limestone. In addition, some bodies of limestone form redeposited horizons in younger volcanic rocks (Sokolov et al., 2015).

At the base of the carbonate sequence there are horizons of limestone breccia composed of slightly rounded debris of limestone cemented by limonite that has replaced calcite (Fig. 13). In the lower part of the sequence grainstone is light grey and partly replaced by limonite. Upward in

IP T

the sequence, light grey grainstone grades into grey fragmental rocks, cut by red and brownish red veinlets, that contain recrystallized detritus of brachiopods, bryozoans, crinoideans and

SC R

corals cemented by clotty calcite. The amount of detritus varies from 10-15 to 30 %.

Further upward in the sequence there is grey pelitomorphic wackestone (Fig. 14). These rocks are calcarenite, with clasts of lime mudstone and volcanic rocks of undetermined composition; the rock texture is clotty. Some samples contain chaotically distributed fragments of crinoids and

U

other echinoderms. Clasts of mudstone are fractured, and numerous micro-fractures are filled

N

with microcrystalline calcite. In this part of the sequence there are rare beds of grey, black and

A

greenish chert up to 1-2 mm thick (Sokolov et al., 2015).

M

Interpretation: Carbonate deposition on basalt and presence of limestone debris in volcanic rocks suggest their synchronous formation in an oceanic island setting. Limestone is fragmental and

ED

contains fossil remnants which indicate detritus supplied by framework builders.

PT

5. Chert and siliceous beds in limestone On the Wrangel Island and in the Kuul (the Kibera Cape) and the Alyarmaut Uplifts similar

CC E

nodular chert occurs in limestone of different ages. Chert forms beds or lenses; as a rule, chert beds are nearly parallel to the overall bedding. Bed thickness is commonly 5-6 mm and rarely 10-12 mm. Chert is generally grey or dark grey; variously colored (grey, black, brown and pink) chert is confined to the Uering Cape and the Wrangel Island. Normally chert is free of

A

fragmental admixtures and is composed of irregularly shaped quartz aggregates of 0.01-0.1 mm in size. In addition to quartz aggregates, chert contains rhomboids of dolomite of 0.1-0.2 mm in size. Some chert samples contain poorly preserved faunal remnants. Chert samples may also contain authigenic mica along cleavage planes, and single crystals and spherical aggregates of pyrite.

Chert of the Polyarnyui Uplift is represented by two types: i) bedded chert associated with limestone; and ii) cryptocrystalline chert associated with basalt.

i) Bedded chert forms concretions, beds and lenses up to several centimeters long within massive limestone. Chert is grey-green (sample 9969/3) and is composed of fine-grained quartz with minor disseminated opaque minerals. Bedding (in fractions of a mm) results from the alternation of poorly fibrous and spherolitic chalcedony. The latter contains rare poorly preserved

IP T

radiolarians.

ii) Some cryptocrystalline chert is brick red and contains small, poorly preserved radiolarians;

SC R

other samples are phthanite-like varieties associated with basalt (sample 9969/2с). Chert is composed of cryptocrystalline quartz aggregates with local admixtures of hydrous iron oxides and aggregates of Fe-chlorite. A spotty texture results from the local presence of larger quartz

U

aggregates. The age of this chert is unknown (Bondarenko, 2004).

N

6. Geochemical data

A

In publications focused on the geochemistry of limestone, studied trace element contents have been normalized to a number of standards, including chondrites, the North American Shale

M

Composition (NASC) and the post-Archean Australian Shale (PAAS). However, Anders and Grevesse (1989) have shown that normalization to С1 chondrite contents is the most informative

ED

method. In this paper, we use normalization to the C1 chondrite standart, as used in other publications on the geochemistry of limestones (Kawabe et al., 1991; Tanaka et al., 2003;

PT

Masumdar et al., 2003).

CC E

Carbonate and non-carbonate phases. In order to know the amounts and composition of noncarbonate phases in our limestone samples, the samples were examined by XRD. In addition, XRD was used to refine our identification of carbonate minerals. The results are shown in Table

A

1.

Salinity. The value of the Sr/Ba ratio in limestone is an important index of sea-water salinity, as it shows the setting of a limestone formation (Bernat, 1972; Wang, 1996; Maslov, 2005; Meng et al., 2017). Near the coast, barium interacts with SO42- and is precipitated from sea-water. In contrast, Sr is not precipitated in the coastal part of a basin and is transported to its distal parts. Because of this, the value of the Sr/Ba ratio is below 1 in basin with freshwater input and above 1 in fully marine basins.

Layers with high and low Sr / Ba ratios intercalated in the Upper and Upper Carboniferous limestone of Wrangel Island, this suggests frequent changes in the amount of fresh-water input that occurred during sedimentation (Fig. 15). The Lower Carboniferous limestones of the Alyarmaut and the Polyarnyui Uplifts have high Sr/Ba values (above 1), indicative of their sedimentation exclusively in a marine setting (Table 2). Low Sr/Ba values are typical of the

IP T

Kibera Cape and suggest the input of fresh water (Table 2).

Rare Earth Elements (REE). The analysis of REE for characterizing the impurity composition in carbonate rocks used in many publications (Kawabe et al., 1991; Zhang and Nozaki, 1996;

SC R

Tanaka et al., 2003 etc). Marine carbonate phase generally contain significantly less REE than detrital clays and heavy minerals (Piper, 1974; Palmer, 1985; Ballanca et al., 1997). The lowest contents of REE are found in the Lower Carboniferous limestone of the Alyarmaut and the Polyarnyui Uplifts and the Bashkirian-Moscovian limestone of the Central tectonic zone of the

U

Wrangel Island (Fig. 16). REE spectra similar to that of the PAAS are characteristic of the

N

Lower and Upper Carboniferous limestones of the Kibera Cape and the Southern zone of the

A

Wrangel Island. Samples from the Krasnyi Flag sequence exhibited anomalous contents of some

particles transported from land.

M

elements (Co, Y, Er, Table 2). The anomalous values probably resulted from the addition of dust

ED

Limestones of the Lower and Upper Carboniferous of the Southern zone of the Wrangel Island and the Kibera Cape show REE distributions similar to that of the PAAS shale normalized to the

PT

C1 chondrite (Fig. 16), which indicates a pronounced influence of terrigenous admixture and suggests close proximity to land. The Upper Carboniferous limestone of the Central tectonic

CC E

zone of the Wrangel Island and the Lower Carboniferous limestone of the Alyarmaut and Polyarnyui Uplifts demonstrate low REE, which can suggest sedimentation in a marine setting, but near surface seawater (Fig. 16, diagram Y/Ho-Y/Yb; Table 2).

A

The diagram of Co/Th versus La/Sc (Fig. 16) demonstrates terrigenous sediment composition and allows distinction of felsic and basic rock sources. The samples studied exhibit the ratios typical of products of the erosion of felsic rocks with value similar to the average composition of the continental crust. The limestone of the Polyarnyui Uplift, however, shows high Co/Th ratio indicating erosion of basic rocks. Some Lower and Upper Carboniferous samples of the Wrangel Island (from the Krasnyi Flag and the Khishchnikov river sections, respectively) were also influenced by erosion of basic rocks, but ratio of Co/Th in these samples is very large (see table

2).We assume these sections received abundant input of fine-grained material derived from the Neoproterozoic basalts.

In summary, the limestones belong to two geochemical types: (1) limestone with flat REE spectra, negative Eu anomalies, and ratios of Co/Th versus La/Sc indicative of carbonate sedimentation in a passive continental margin setting with a predominantly felsic rock detrital source, and (2) limestone with enrichment in heavy REE, a small negative Eu anomaly, and high

IP T

Co/Th values typical of the samples of the Polyarnyui Uplift and indicative of basic rocks as the detrital source.

SC R

Ratios of light REE (LREE) to heavy REE (HREE) are indicative of the paleogeodynamic setting of carbonate sedimentation. Patterns in REE ratios were demonstrated for carbonate rocks in the southern part of the Siberian platform (Letnikova, 2003, 2005). The LREE/HREE ratio in limestone of the Polyarnyui Uplift is 2.9-3.9 (Table 2) and corresponds to that in sediments of

U

oceanic islands. The values of this ratio are 6-10 for the limestone of the Alyarmaut Uplift, 7-12

N

for the Lower Carboniferous limestone of the Southern zone of the Wrangel Island, and 4-10 for

A

the limestone of the Central zone. These ratios suggest that these limestones were deposited in a passive continental margin setting. The value of this ratio reaches 12-20 in the Upper

M

Carboniferous limestone of the Wrangel Island and in Lower and Upper Carboniferous limestone of the Kibera Cape; these high values are due to a high amount of a terrigenous admixture typical

ED

of settings close to land. The LREE/HREE ratio is 3-4.2 in the Bashkirian-Moscovian deposits of the Krasnyi Flag River area of the Wrangel Island, however, which suggests deposition in an

CC E

PT

isolated carbonate platform setting.

7. Isotope composition of oxygen and carbon The least recrystallized limestone samples with the least terrigenous admixture were used for

A

isotope investigations. Prior to isotope data analysis, the consequences of post-sedimentary processes on the isotope composition of the studied deposits were assessed. For this purpose, the Mn/Sr ratio was used (Brand, Veizer, 1980; Denison et al., 1994; Gorokhov, 1996; Kuznetsov et al., 2012). In spite of intensive deformation, the Mn/Sr values are very low—thousandths of a percent and less (Table 2), which suggests no secondary carbonitization and an insignificant impact of post-sedimentary processes on the isotope composition of the studied carbonates.

Carbon. In marine basins, the value of δ13С varies from –2 to +2‰ (Veizer et al., 1999; Prokoph et al., 2008; Semikhatov et al., 2004). High values of δ13С are interpreted as typical of shallow-water marine settings having a high bioproductivity in an arid climate. High values of δ13С are also characteristic of settings such as evaporite basins associated with a carbonate platform. Light (low) δ13С isotope values are typical of carbonate in fresh-water basins. Low values of δ13С can also indicate fluctuations of sea level and high temperatures during carbonate

IP T

sedimentation.

High (heavy) isotope compositions of carbon (Table 3) are typical of the Lower Carboniferous limestones of the Alyarmaut Uplift (the average δ13С is 0.69) and the Polyarnyui Uplift (the

SC R

average δ13С is 2.63), the Upper Carboniferous samples of the Central zone of the Wrangel Island (the average δ13С is 4.97), and the sample (M10/11) of the Kibera Cape (δ13С is 4.3) (Fig. 15, Table 3).

U

Lighter isotope compositions of carbon are found in the Lower Carboniferous samples of the

N

"evaporite" member of the Khishchnikov River of the Wrangel Island (δ13С varies from – 8,7 to

A

-2,6‰) and the Alyarmaut Uplift (δ13С varies from –4,4 to –1,9‰). Samples of the Lower Carboniferous of the Ptichii Bazar Cape have low (-4.5 and -3.2) and high (5.4) values (Fig. 15,

M

Table 3).

ED

Oxygen. In marine basins the value of δ18O is about 28‰ (Bruckschen et al., 1999). A value of δ18O that is lower compared to that in normal marine carbonate can indicate lower salinity of the

PT

water in a carbonate basin (Beauchamp et al., 1987; Kuleshov and Sedaeva, 2009). In most of the samples analyzed, the δ18O values are lower than those of normal marine

CC E

carbonates and range from 15-25‰. Two samples (sample 458/5 from the Alyarmaut Uplift and sample М10/17-2 from the Kibera Cape) have δ18O of 28-28,2‰. Carbonates of the Polyarnyui Uplift have values closer to those of normal marine carbonates (22.2-23.9‰).

A

In the sequences of the Wrangel Island, the average values of δ18O decrease in the samples from Lower to Upper Carboniferous deposits. In the samples of the Lower Carboniferous the average values of δ18O range from 18.6 to 23.43 ‰; in the samples of the Upper Carboniferous they vary from 17.27 to 21.88 ‰ (Table 3). These data suggest an increasing influx of isotopically light river water that reduced the salinity of the basin in the Late Carboniferous.

The values of δ18O significantly differ between the sequences of the Southern and Central tectonic zones of the Wrangel Island. The limestones of the Southern zone show δ18O values that range from almost normal marine (max δ18O 24.8 ‰) to very light (δ18O 14.1-12,2‰, Fig. 15, Table 3). This suggests an unstable setting on a shallow-water shelf characterized by periods of desalinization and salinization. Limestone of the Central zone exhibits less variable δ18O values, ranging from 18.2-26.4 ‰ in Lower Carboniferous rocks, and from 19.4-25.2 ‰ in the

8. Settings of sedimentation and paleogeographic reconstructions

IP T

Upper Carboniferous deposits.

Despite many years of investigations of Chukotka’s stratigraphy, the Carboniferous fauna of this

SC R

region is still not clearly understood. However, new studies undertaken in the last few years have helped to elucidate the fauna and the stratigraphic sequences of Carboniferous in different tectonic elements. Faunal determinations and their locations are shown in Figure 3, and include

U

both published data and new findings of the authors from field trips made in 2004-2014.

N

Carbonate sedimentation in some parts of our study area lasted from the Tournaisian Stage to

A

the Moscovian Stage, and probably into the Kasimovian Stage. The period of carbonate sedimentation was significantly shorter in the south (Polyarnyui Creek) than in the north (the

M

Wrangel Island). Based on these stratigraphic data, two paleogeographic maps for the Eastern

were compiled.

ED

Arctic in the Tournaisian-Serpukhovian (Fig. 17a) and in the Bashkirian-Moscovian (Fig. 17b)

PT

The Early Carboniferous

Wrangel Island. In the beginning of the Early Carboniferous, a shallow-water shelf with local

CC E

organogenic buildups and intrashelf uplifts (Sokolov et al., 2017) existed in the Central tectonic zone of present-day of the Wrangel Island (Fig.14a). These uplifts (or a land mass) were eroded and the products of this erosion (sandy and silty limestones) were deposited around the uplifts. A single measurement ofcross-bedding indicates that clastic material was transported from the

A

southwest to the northeast. We interpret that this current direction indicates that the uplift was situated near the middle part of the present-day Neizvestnaya River.

Organogenic edifices were mainly composed of corals, brachiopods and microfauna, with algae also present. Fauna of this type is commonly confined to the outer carbonate platform and shallow shelf margin. In the Southern tectonic zone of the Wrangel Island, biohermal buildups

formed on a shallow-water shelf in front of an "ephemeral" delta during arid episodes characterized by no supply of terrigenous material.

At the end of the Early Carboniferous, inner ramp lagoonal sedimentation settings were dominant. Shallow-water areas periodically became hypersaline. Evidence of these conditions is found in strata on the upper reach of the Krasnyi Flag River (the Central tectonic zone) and in the Southern tectonic zone near the Ptichii Bazar Cape and the Khishchnikov River (Fig. 17a). It

IP T

is about beds of evaporates in the carbonate sections. The depositional setting in these areas consisted of coastal marine zones that experienced periods of exposure and flooding. During exposure periods, the accumulated sediments were subjected bioturbation and drying with

SC R

forming desiccation cracks (Fig. 6). During wetter periods, limestones were reworked and redeposited by the action of storms and waves and formed fragmental limestones.

Kibera Cape. To the south, in the vicinity of the Kibera Cape, layers and lenticular horizons of

U

coarse-grained deposits that increase upward in grain size throughout the section accumulated on

N

a shallow-water shelf in the Tournaisian-Visean Time. Conglomerates accumulated in shallow-

A

water conditions near a source composed of schist and granite. Thin beds of different compositions suggest a source made up of small, diverse uplifted areas that

M

were rapidly eroded. It is probable these sources were located at the margin of a carbonate platform characterized by periodic supply of terrigenous material and fresh water input from the

ED

nearest land mass. Geochemical data show REE distributions and negative Eu anomalies very similar to those of the limestones of the Wrangel Island, and support the interpretation of a

PT

passive continental margin setting.

CC E

On the basis of measurements of cross-bedding and pebble imbrication, we suggest that clastic material was transported from the north and the northeast (Fig. 17a). According to Rogozov et al. (1968, 1970), pebble size increases from the southeast to the northwest of the Kuul Uplift. So,

A

the eroded source was located to the North of the modern uplift.

Alyarmaut Uplift. Further to the south, in the Alyarmaut Uplift, limestones accumulated on a shallow-water zone dipping toward the continental slope. Marine conditions in this area weren't disturbed by any influxes of fresh water with terrigenous material. The upward change from dark, almost black limestone to light grey limestone and then sugary-textured, white varieties suggests that conditions became more and more typically marine.

The Lower Carboniferous limestones on the Wrangel Island and in the Kuul and the Alyarmaut Uplifts formed in marine settings. The sequences exhibit evidence for periodic influxes of fresh water. This is suggested by analyses of the salinity index (Sr/Ba) and isotopic data (δ18O, δ13C). REE distributions imply that carbonate accumulated adjacent to a continental land mass. Beds with low and high amounts of terrigenous admixtures alternate in the sequence and indicate that the carbonate accumulated near land, wich was a periodic source of clastic material. Analyses of the REE and trace-element ratios indicate that the Lower Carboniferous carbonates contain

IP T

detrital material derived from reworked felsic rocks. In addition, isotopic data indicate that the marine basin became less saline in the end of Lower Carboniferous and we suggest that the

SC R

shallow-water shelf experienced a transgression at the end of the Early Carboniferous.

Polyarnyui Uplift. Limestones of the Polyarnyui Uplift accumulated in a fundamentally different setting; these limestones rest on oceanic basalts. The carbonates accumulated on an isolated seamount with no influx of fresh water. The isotopic data (δ18O, δ13C) are consistent

U

throughout the sequence and are typical of a stable marine setting. Limestones are enriched in

N

heavy REE; the Co/Th ratios indicate input of detritus derived from mafic igneous rocks. Deeper

A

water conditions are suggested by the types of chert found in these limestones. Both types of chert in the Polyarnyui Uplift differ from those seen elsewhere; the presence of radiolarians in

M

these cherts is consistent with their interpretation as deeper water strata.

ED

The Late Carboniferous

At the end of the Early Carboniferous or the beginning of the Late Carboniferous, carbonate

PT

sedimentation ended in the Alyarmaut and Polyarnyui Uplift areas (Fig. 17b). A hiatus is recorded in the shallowest water settings of the Central tectonic zone of the Wrangel Island prior

CC E

to the deposition of Upper Carboniferous strata; conglomerates and gravels constitute the basal Bashkirian Stage deposits (Fig. 3). These coarse-grained rocks have a thin thickness and varied in composition, suggesting small local sources. The overlying biogenic-fragmental limestones formed in a shallow water setting that received reworked debris from banks and

A

bioherms. However, no coeval bioherms, banks or reefs are preserved in this area.

The Southern tectonic zone of the Wrangel Island shows evidence for shallow water shelf settings. The boundary between Lower and Upper Carboniferous carbonates is marked by a faunal change. Upper Carboniferous strata include biohermal buildups made up of bryozoans, with lesser brachiopods, algae, and cyanobacterial mats; rock types include boundstone and rudstone. Algal plains developed in depressions adjacent to the bioherms; thin turbidites were

derived from erosion of the bioherms. Newly recognized foraminifers in the limestone of the Wrangel Island have a wide age range. They are known in Moscovian-Asselian (Middle Pennsylvanian-Lower Permian) deposits of Arctic Canada (Pinard and Mamet, 1998), but they are especially characteristic of Moscovian-Kasimovian deposits in this region. These forms are typical and for Cisuralian deposits, for example, for upper part of the Treskelodden Beds in Spitsbergen (the Asselian-Lower Artinskian Stages of the Cisuralian Series of the Permian System) (Blazejowski, 2009); they also occur in Artinskian deposits of the Kotel'nii Island and in

IP T

the Gzhelian-Asselian of the Pechora basin in Russia. In the middle part of the Urals, this fauna is confined to the Kungurian Stage of the Cisralian Series (Filimonova, 2016). Thus, this foraminiferal fauna is widely present in Carboniferous and Permian deposits of the Arctic. The

SC R

joint presence of this fauna with Lower Pennsylvanian corals in our study area, allows us to interpret a Bashkirian-Moscovian age for our rocks. Megafossils, and in particular the occurrence of coral colonies, indicate warm-water conditions during deposition of the Carboniferous strata of the Wrangel Island; a near-equatorial setting was suggested by Kos'ko et

N

U

al. (2003).

A

The carbonates of the Kibera Cape, like the limestones of the Wrangel Island, accumulated in depressions within shelf areas to which terrigenous material was periodically supplied. The

M

geochemistry of these rocks is similar to that of the carbonates of the Wrangel Island (Table 2).

ED

Facies and isotope characteristics of Upper Carboniferous rocks on the Wrangel Island and the Kibera Cape indicate a shallow-water shelf setting. Fully marine conditions alternate with

PT

hyposaline ones, as shown by changes of Sr/Ba ratios in the sequence. The Upper Carboniferous deposits contain more terrigenous material than the Lower Carboniferous deposits. This suggests

CC E

an increase in terrigenous material supplied from an adjacent continental landmass and therefore tectonic uplift of the terrigenous material source. Geochemical data indicate that the terrigenous material was derived mainly from felsic rocks. The only exception is the carbonates of the

A

Central zone of the Wrangel Island, which contain material derived from basic rocks.

9. Discussion The existence of the Hyperborean platform (or the paleocontinent of Arctida) is documented in numerous publications (Shatskii, 1935; Zonenshain and Natapov, 1987; Vernikovsky, 1996; 2011; Embry, 1993, 2009; Khain and Filatova, 2009; Lobkovsky et al., 2011; Laverov et al., 2013). According to these studies, fragments of the Neoproterozoic Arctida craton are exposed along the continental margin of the Arctic basins in the Novaya Zemlya Archipelago, the

Severnaya Zemlya Archipelago, the De Long Islands, Taimyr and Seward Peninsulas, the Brooks Range, the Canadian Arctic Archipelago, in Chukotka, the New Siberian Islands and the Wrangel Island. Recently obtained data indicate that central parts of the Arctic Ocean basin are also fragments of the ancient continent of Arctida (Laverov et al., 2013; Lobkovsky et al., 2011).

In Chukotka, Devonian-Permian sedimentary rocks with abundant and diverse faunas was accumulated in a shallow-water shelf setting that received terrigenous material transported from

IP T

the north (Bogdanov and Til'man, 1964, 1992; Rogozov et al., 1968; Ustritskii, 1975; Zonenshain et al., 1990; Golonka, 2011). Stratigraphic studies indicate that the most complete sequence of carbonate rocks is preserved in the Southern Tectonic zone of the Wrangel Island.

SC R

The stratigraphic interval of carbonate sedimentation decreases to the south (from two series Missisipian and Pennsylvanian in the Wrangel Island to the Visean Stage in the Polyarnyui Uplift, Fig. 18).

U

Our comprehensive analyses of biostratigraphy, lithology and geochemistry indicate that

N

Carboniferous sedimentation on the Wrangel Island and in the Kuul and Alyarmaut Uplifts took

A

place in a carbonate platform setting on a passive continental margin. In the Polyarnyui Uplift of the South Anyui suture, LREE/HREE ratios indicate that limestone was accumulated in a

M

deepwater oceanic seamount setting (Fig. 16E).

ED

Unfortunately, we can only assume the size of the carbonate platform, since the position and distribution of facies in the modern structure of Chukotka are obscured by intense deformations.

PT

The current distance between the most widely spaced sections (those of the Alyarmaut Uplift and the Wrangel Island) is about 600 km. We suggest that this distance was

CC E

originally greater prior to fold-and-thrust deformation.

Extensive carbonate sedimentation during the Early Carboniferous became less widespread during the Late Carboniferous. This change was accompanied by an increase in terrigenous input

A

into the carbonate depositional settings of the Southern tectonic zone of the Wrangel Island and the Kibera Cape and these settings became shallower (Fig. 17a and b). These data indicate uplift of the carbonate platform and the terrigenous source areas during the Late Carboniferous, which resulted in increased supply of terrigenous material to the platform.

The Upper Carboniferous carbonates of the Central tectonic zone of the Wrangel Island contain dust particles. The low terrigenous content in the sequences of the Central tectonic zone of the

Wrangel Island is attributed to a position behind a barrier, formed during accumulation of the "lower" carbonate unit, which stopped input of clastic material. This barrier originated as an uplifted zone within the basin and and is made up of Devonian and Neoproterozoic rocks. It produced material transported from the northeast and east, as indicated by measurements of cross bedding.

Conglomerates at the base of the Yunona Formation of the Kuul Uplift (the Kibera Cape) can be

IP T

related to formation of an intrabasin uplift composed of granite. The geochronology data available for pebbles from conglomerate and for granite of the Kibera Cape (Luchitskaya et al., 2015; Lane et al., 2015) indicate U-Pb zircon ages of 355-361 and 359±3 Ma for granite pebbles

SC R

and 351.4±5.6 and 353±5 Ma for the Kibera Cape granite. This granite probably experienced rapid exhumation and erosion; the Early Carboniferous age of this granite corresponds to the timing of the Ellesmerian orogeny tectonic event (Trettin, 1991; Verzhbitsky et al., 2012; 2015;

U

Hadlari et al., 2014), (Fig. 18).

N

According to the latest geochronological time scale (Cohen et al., 2013), exhumation took place

A

during the Tournaisian and can be correlated with the unconformity in the Central zone of the Wrangel Island, which resulted in cessation of terrigenous sedimentation in this area and

M

wasaccompanied by local uplifts on the shelf. The Ellesmerian orogeny in the Arctic margin of Chukotka was first distinguished in the Wrangel Island (Verzhbitsky et al., 2012; Verzhbitsky et

ED

al., 2015). Newly obtained data significantly expand these previous suggestions.

PT

An unconformity at the base of the Serpukhovian Stage is assumed because of the termination of carbonate sedimentation at this time in the Polyarnyui and Alyarmaut Uplifts. On the Wrangel

CC E

Island Mississippian units are Tournaisian-Visean-Serpukhovian in age (Kos'ko et al., 2003). The relationship between different units is not always clear, so they are difficult to correlate with each other. U-Pb ages of detrital zircons from the Carboniferous sandstones of the Southern tectonic zone of the Wrangel Island (the Ptichii Bazar Cape and the Khishchnikov River)

A

indicate the erosion of rocks dated at 420-490 Ma and 500-800 Ma; populations older than 800 Ma are dominant and constitute 50-60 % of total analyzed zircons (Miller et al., 2010).Similar zircon populations were found in Carboniferous samples from the Neizvestnaya River area (2006 collection) by the authors.

A stratigraphic unconformity marked by a basal conglomerate within the Bashkirian Stage is found only in the Central tectonic zone of the Wrangel Island. Beds of conglomerate are thin,

contain debris of underlying rocks, and were derived from intrabasin uplifts composed of Neoproterozoic basalt and granitoid as well as Silurian-Devonian slate and limestone. The Neoproterozoic ages of basalt and granotoid are proved by U-Pb dating (Sokolov et al., 2017). The biogenic and bioclastic limestones overlying the conglomerates include numerous fossils of Late Carboniferous age as well as coral debris derived from older (Lower Carboniferous and Silurian) deposits (Sokolov et al., 2017).

IP T

One more unconformity marked by conglomerate is found at the base of the Middle-Upper Permian deposits of the Wrangel Island. These conglomerates look similar to those of the Bashkirian Stage but differ in microfauna (Sokolov et al., 2017). In Chukotka, the hiatus in

SC R

sedimentation corresponds to the Late Carboniferous and the Early Permian.

Thus, three unconformities were distinguished in the Carboniferous and the Permian. The correlation of these events is shown in Fig. 18, which illustrates the main sedimentologic and

N

U

tectonic events in the region.

A

The first local tectonic event is related to the Ellesmerian orogeny. The age of this event is constrained by the U-Pb zircon ages of the Kibera Cape rocks and it is correlated with the end of

M

terrigenous sedimentation in the sequences of the Central zone of the Wrangel Island. Carbonate sedimentation ended on the outer carbonate platform (the Alyarmaut Uplift) and in the oceanic

ED

basin (the Polyarnyui Uplift) in the beginning of the Serpukhovian Stage. Evaporites in shallowmarine environments ceased sedimentation at about Mid Visean (Southern zone of the

PT

Wrangel Island) and Late Visean (Central zone of the Wrangel Island). This is all the consequences of Ellesmerian orogeny, which began in the Late Devonian (Verzhbitsky et al.,

CC E

2015; Sokolov et al., 2017).

Local tectonic reorganization is marked by the formation of conglomerates and gravels at the base of the Bashkirian limestones of the Wrangel Island. A weathering rind was produced by the

A

prolonged exposure of the basement metamorphic rock complex in this area. Mature components (rounded debris of quartz and quartzite) derived from this crust of weathering are found in these coarse-grained rocks, together with basalt, limestone and granite.

In the Late Carboniferous to the Early Permian, Arctida, as part of Euro-America, approached Siberia. This movement resulted in the closure of the Uralian Ocean and the formation of the Taimyr orogenic belt and the South Anyui oceanic gulf (Vernikovsky, 1996; Zonenshain,

Natapov, 1987, Zonenshain et al., 1990, Laverov et al., 2013). During the Permian-Middle Triassic, following the closure of the Uralian Ocean, the Proto-Arctic Ocean narrowed and transformed into a gulf of the Pacifica Ocean. The continued tectonic history of the region reflects deformation related to the collision of the active continental margin of the North Asian continent and the Chukotka microcontinent. In the Late Mesozoic-Cenozoic, the break-up of Arctida resulted from the consecutive opening of the Amerasian and Eurasian basins.

IP T

10. Conclusions 1. Facies and geochemical data indicate that Carboniferous deposits of the Wrangel Island, the Kibera Cape and the Alyarmaut Uplift originated on a carbonate platform that was part of the

SC R

passive continental margin of Arctida (the Hyperborean platform). Limestone of thePolyarnyui Uplift was formed on an isolated seamount in the oceanic basin.

2. Limestones of the Wrangel Island, the Kibera Cape and the Alyarmaut Uplift have similar

U

geochemical and isotopic compositions and accumulated in a marine basin at a significant

N

distance from major land masses. The isotope composition is consistent and indicates marine

A

conditions.

M

3. In the Early Carboniferous, the shallowest areas of the carbonate platform were located in present-day of the Wrangel Island (the Krasnyi Flag and Neizvestnaya rivers) and the Kibera

ED

Cape. In the Southern tectonic zone and in the Alyarmaut Uplift, carbonate accumulated in areas more remote from land and characterized by uneven topography. In the Late Carboniferous, the

PT

area of carbonate sedimentation was reduced and deposits accumulated in a shallower setting.

CC E

Sedimentation was completely terminated in the south, in the Polyarnyui and Alyarmaut Uplifts.

4. A new paleogeographic model of sedimentation for the eastern Arctic is proposed based on the correlation of carbonate rocks in the studied sequences and analyses of their isotopic and geochemical characteristics. The shallower water shelf setting that existed in the Mississippian

A

became even shallower in the Pennsylvanian. Carboniferous sequences are transgressive. Biohermal/reef buildups formed during arid periods in front of “ephemeral” deltas when terrigenous material wasn’t supplied.

5. The faunal assemblages indicate warm-water conditions prevailed during carbonate sedimentation, as seen elsewhere in coeval carbonate deposits of the Arctic.

6. Three stages of tectonic activity affected sedimentation on the carbonate platform. The boundary between the Visean and Serpukhovian Stages corresponds to regional uplift of the carbonate platform and termination of carbonate sedimentation in the oceanic basin. Tectonic reorganization within the Bashkirian Stage and at the beginning of the Early Permian is expressed only in the sequences of the Wrangel Island. Future investigations may recognize them in other localities.

IP T

Acknowledgements This study was supported by the Russian Science Foundation (project No 16-17-10251). Field works were financed by the RFBR grant and by the contract No 0441414/0115Д (Wrangel

SC R

Island) between GIN RAS and Rosneft’ company “RN-Shelf-Far East” in 2014.We are very grateful reviewer Julie Dumoulin whose polishing work and constructive comments have greatly improved our manuscript; comments of anonymous reviewer were also very useful.

N

U

References

A

Aksyonova, V.D., 1966. The main regularities of the placement of gold mineralization in the Central part of Anyui zone. Chukotsky TGF. [in Russian]. http://geo.mfvsegei.ru/200k/r-58/r-58-

M

35,36/Download/Zap_R-58-XXXV,XXXVI.pdf

ED

Anders, E., Grevesse, N., 1989. Abundances of the elements: Meteoritic and solar. Geochim.

PT

Cosmochim. Acta. 53, 197–214.

Beauchamp, B., Oldersham, A.E., Krouse, H.R., 1987. Upper Carboniferous to Upper Permian

CC E

13C-enriched primary carbonates in the Sverdrup Basin, Canadian Arctic: comparisons to coeval Western North American ocean margins. Chem. Geol. (Isotope Geoscience Section) 65, 391– 413. In: Isotopes in the Sedimentary Cycle, N. Clauer and S. Chauhuri (eds.). Matched ISSN :

A

0009-2541 https://www.sciencedirect.com/science/article/pii/0168962287900169

Belik, G. Ya., and G. M. Sosunov, 1969, Geologic map of USSR: Northeastern Geological Directorate, Anyuisko-Chaunskaya Series R-58-XXIX, XXX, scale 1:200,000, 1 sheet. [in Russian].http://www.geokniga.org/maps/4877

Bellanca, A., Masetti, D. and Neri, R., 1997. Rare earth elements in limestone/marlstone couplets from the Albian-Cenomanian Cismon section (Venetian region, northern Italy):

assessing REE sensitivity to environmental changes. Chem. Geol. 141, 141–152.

Bernat M., Church Th., Allegre C.J., 1972. Barium and strontium concentrations in Pacific and Mediterranean sea water profiles by direct isotope dilution mass spectrometry. NorthHolland publishing company. Earth Planetary Sci. Lett. 16, 75-80.

Blazejowski, B., 2009. Foraminifers from the Treskelodden Formation (Carboniferous Permian)

IP T

of south Spitsbergen. Polish Polar Research 30, 193-230. Doi: 10.4202/ppres.2009.10.

Bogdanov, N.A. and Tilman, S.M., 1992. Tectonics and Geodynamics of Northeastern Asia

SC R

(Explanatory Notes to the Tectonic Map of Northeastern Asia on a Scale of 1: 5000000)(Inst. of Lithosphere, Moscow), 54. [in Russian].

Bogdanov, N.A., Tilman, S.M., 1964. General features of the development of the Paleozoic structures of the Wrangel Island and the western part of the Brooks Range (Alaska). In: Muratov

U

M.V., Ed., Folded regions of Eurasia (Materials of the meeting on problems of tectonics.

A

N

Moscow. Nauka, 219-229. [in Russian].

M

Bondarenko, G. E., 2004.Tectonics and geodynamics of evolution of the Mesozoic in northern framework of the Pacific Ocean, Doctoral Dissertation in Geology and Mineralogy. Moscow Univ.,

Moscow. [in

Russian].

ED

State

http://www.dissercat.com/content/tektonika-i-

PT

geodinamicheskaya-evolyutsiya-mezozoid-severnogo-obramleniya-tikhogo-okeana

Bondarenko, G. E. and Luchitskaya M. V., 2003. The Mesozoic tectonic evolution of the

CC E

Alyarmaut Uplift, Western Chukotka. Byull. Mosk. O-va. Ispyt. Prir., Otd. Geol. 78 (3). 25– 37 [in

Russian].

http://docplayer.ru/amp/53422935-Bondarenko-g-e-luchickaya-m-v-

vniipromgaz-moskva-geologicheskiy-institut-ran-moskva.html

A

Brand, U., Veizer, J., 1980. Chemical diagenesis of a multicomponent carbonate system -1: Trace

elements. Jour.

Sediment.

Petrol. 50, 1219-1236. Matched

ISSN

:

0022-4472

https://www.ncbi.nlm.nih.gov/labs/journals/j-sediment-petrol/

Bruckschen P., Oesmann S., Veizer J., 1999. Isotope stratigraphy of the European Carboniferous. Proxy signals for ocean chemistry, climate and tectonics. Chem.Geol. 161, 127163.

Byalobzhesky, S. G. and Ivanov, O. N., 1971. Thrust structures of Wrangel Island. Mesozoic Tectogenesis. Proceedings of the 7th Session of Scientific Council on Tectonics of Siberia and Far East (Northeastern Interdisciplinary Res. Inst. Magadan), 73–80. [in Russian].

Chernyak, G.E., Kameneva, G.I., 1976. Carboniferous and Permian strata of Wrangel Island.

IP T

Doklady Akademii Nauk SSSR 227, 954–956. [in Russian].

Cohen, K.M., Finney, S.C., Gibbard, P.L. & Fan, J.-X., 2013; (updated). The ICS International Chronostratigraphic

Chart. Episodes 36, 199-204.

SC R

URL:http://www.stratigraphy.org/ICSchart/ChronostratChart2015-01.pdf Matched ISSN : 07053797

Denison, R.E., Koepnick, R.B., Fletcher, A., Howell, M.W., Callaway, W.S., 1994. Criteria for

U

the retention of original seawater 87Sr/86Sr in ancient shelf limestones. Chem. Geol. 112, ½,

A

N

131-143. https://www.sciencedirect.com/science/article/pii/0009254194901104

M

Eardly, A.J., 1948. Ancient Arctic. Journal of Geology. 56, 409-436. Embry, A., 1993. Crockerland — the northern source area for the Sverdrup Basin, Canadian

ED

Arctic Archipelago. In: Vorren, T., Bergsager, E., Dahl-Stamnes, O., Holter, E., Johansen, B., Lie, E., Lund, T. (Eds.), Arctic Geology and Petroleum Potential. Norwegian Petroleum Society Publication

2,

pp.

205–216.

PT

Special

https://www.sciencedirect.com/science/article/pii/B9780444889430500186

CC E

Embry, A., 1993. Crockerland – the northern source area for the Sverdrup Basin, Canadian Arctic Archipelago. In: Vorren, E. Bergsager, O. Dahl-Stamnes, E. Holter, B. Johansen, E. Lie and T. Lund (Ed.), Arctic Geology and Petroleum Potential. Norwegian Petroleum

A

Society. Spec. Publication. 2, 205–216.

Fedorowski, J., Stevens, C. H. 2014. Late Carboniferous colonial Rugosa (Anthozoa) from Alaska. GeologicaActa. 12. 3, 239 - 267. http://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2014.12.3.6

Fedorovsky, V.S. & Shilo, N.A. (eds.), 1980. Tectonics of the continental margins of the Northwestern Pacific Ocean. Moscow. Nauka, 285. [in Russian].

Filimonova, T.V., 2016. A new Pennsylvanian (Late Carboniferous)-Permian foraminiferal genus (Lateenoglobivalvulina nov.gen., Biseriamminoidea) and its paleobiogeographic distribution. Revue de micropaleontology. 59. 188-199.

IP T

https://www.sciencedirect.com/science/article/pii/S0035159816300034?via%3Dihub

Ganelin, V.G., Matveev, A.V., Kropacheva, G.S., 1989. Upper Paleozoic of Wrangel Island.

SC R

Leningrad. VSEGEI. [in Russian].

Gromov, L.V., Kiryushina, M.T., 1947. Wrangel Island. In Geology of the USSR. Geology. XXVI. Islands of Soviet Arctic Region. Gos. Izd. Geol. Lit., Moscow. Nedra, 388-406.[ in

U

Russian].

N

Golonka, J., 2011. Phanerozoic palaeoenvironment and palaeolithofacies maps of the Arctic

A

region. In: Spencer, A. M., Embry, A. F., Gautier, D. L., Stoupakova, A. V. & Sørensen, K. (eds) Arctic Petroleum Geology. Geological Society, London, Memoirs, 35, 79–129. 0435-

M

4052/11/$15.00 # The Geological Society of London 2011. DOI: 10.1144/M35.6.

ED

Gorodinskii, M.E., 1963. Geological sketch of central regions of Chukotka. In: Materials on

PT

geology and mineral deposits of USSR North-East. 16, 56-66. (in Russian).

Gorodinskii, M.E., 1959. Scheme of Stratigraphy of Mesozoic deposits in the western part of

CC E

Chaunsky district. In: Proceedings of the interdepartmental meeting on the development of unified stratigraphic schemes of the North-East of the USSR, 1957 (reports), Magadan, 242-245. (in Russian).

A

Gorokhov, I.M., 1996. Diagenesis of carbonate sediments: geochemistry of dispersed elements and strontium isotopes. Lithology and paleogeography. 4, 141-164. (in Russian).

Hadlaril T., Davis W.J., Dewing K., 2014. A pericratonic mod- el for the Pearya terrane as an extension of the Fran- klinian margin of Laurentia, Canadian Arctic // Geol. Soc. Amer. Bull. 126. 3–4. 182–200. http:/dx.doi.org/10.1130/B30843.1.

Harrison, J.C., St-Onge, M.R., Petrov O.V., Stelnikov, S., Lopatin B., Wilson, F., Tella, S., Paul, D., Lynds, T., Shokalsky, S., Hults, C., Bergman, S., Jepsen, H.F., and Solli, A. 2008. Geological map of the Arctic; Geological Survey of Canada, Open File 5816, Scale 1:5 000 000, Sheet 1 of 5. Geology.

Henderson, S.M., Cecil, M.P., Harrison, J.K., 1991. Carboniferous conodonts of the Wrangel Island. In: Geology of the folded frame of the Amerasian sub-basin. St. Petersburg.

IP T

VNII Okeangeologiya, 70-77. (in Russian).

Ivanov, K.S., 1987. Methods of searching and separation conodonts. Method. Recommendations.

SC R

Sverdlovsk: UNSC of the USSR Academy of Sciences, 118. (in Russian).

Ivanov, O.N., 1973. Stratigraphy of Wrangel Island // Izvestia AN SSSR. Series geology. 5, 104-

U

114. (in Russian).

N

Kameneva, G.I., 1977. On the question of the tectonic position of Wrangel island and its

A

structural ties with Alaska in the Paleozoic. In: Tectonic of Arctic, folded basement of shelf

M

sedimentary basins. 1. Leningrad. NIIGA, 122-131. (in Russian).

Kameneva, G.I., 1975. Structure of the Central part of Wrangel Island. In: Geology and mineral

PT

300-325. (in Russian).

ED

deposits of New Siberian Islands and Wrangel Island. Collection of papers. Leningrad: NIIGA,

Kameneva, G.I., Chernyak, G.E., 1975. Carboniferous and Permian deposits of the Wrangel

CC E

Island. In: Upper Paleozoic of the Northeast of the USSR. Leningrad. NIIGA, 76-79. (in Russian).

Karandashev, V.K., Turanov, A.N., Orlova, T.A., Lezhnev, A.E., Nosenko, S.V., Zolotareva,

A

N.I., Moskvina, I.R., 2007. Application of massspectrometry with inductively coupled plasma to elemental analysis of environmental objects. Zavodskaya Laboratoriya. Diagnostika Materialov 73 (1), 12–22.

Katkov, S.M., 2014. Analysis of the deformation events of the Paleozoic-Mesozoic strata of Cape Kiber (Central Chukotka). In: Gold & Technology. 4 (26). 50-53. (in Russian).

Katkov, S.M., Miller, E.L., Toro, J., 2010. Structural assemblies and age of deformation in the Western sector of the Anyui-Chukotka Fold system, Northeastern Asia. Geotectonics. 5, 424442.

Kawabe, I., Kitahara, Y., and Naito, K., 1991. Non-chondritic yttrium/holmium ratio and lanthanide tetrad effect observed in pre-Cenozoic limestones. Geochemical Journal. 25, 31-41.

IP T

Khain, V.E., Filatova, N.I., 2009. From Hyperborean platform to Arctida: to the problem PreCambrian Craton of the Central Arctic. Dokladi Academii Nauk Rossii. 428. 2, 220-224.

SC R

(In Russian).

Khanchuk, A.I., Ed. 2006. Geodynamic, Magmatism, and Metallodeny of the Eastern Russia. Vladivostok. Dal'nauka. 1, 572. (in Russian).

U

Kos’ko, M.K., Sobolev, N.N., Korago, E.A., Proskurnin, V.F., Stolbov, N.M., 2013. Geology of

Russia.

Neftegasovaya

geologia.

Teoria

I

practica.

8.

2,

1-36.

A

of

N

Novosibirskian island – a basis for interpretation of geophysical data on the Eastern Arctic shelf

M

http://www.ngtp.ru/rub/5/17_2013.pdf (in Russian).

Kos’ko, M. K., Avdyunichev, V. V., Ganelin, V. G., Opekunov, A. Yu, Opekunova, M. G.,

ED

Cecile, M. P., Smirnov, A. N., Ushakov, V. I., Khandozhko, N. V., Harrison, J. C., and Shul’ga, D. Yu., 2003. The Wrangel Island: geological structure, mineragenesis, environmental geology

PT

Saint Petersburg. VNII Okeangeologia. 137. (in Russian): Kos’ko, M. K., M. P. Cecile, J. C. Harrison, V. G. Ganelin, N. V. Khandoshko, and B. G. Lopatin, 1993. Geology of Wrangel

CC E

Island, between Chukchi and East Siberian seas, northeastern Russia: Geological Survey Canada Bulletin. 461, 101.

Kuleshov, V.N.,Sedaeva,K.M., 2009. Geochemistry of isotopes (δ13c and δ18 O) and

A

depositional environment of the upper kazanian carbonate sediments in the volga-vyatka interfluves. Lithology and mineral resources. 44. 5, 465-481.

Kuznetsov, A.B., Gorokhov, I.M., Semikhatov, M.A., 2012. The Sr isotope composition of the world ocean, marginal and inland seas: Implications for the Sr isotope stratigraphy. Stratigraphy and Geological Correlation. 20. 6, 501-515.

Lane, L.S., Cecile, M.P., Kos’ko, M.K., Layer, P.W., Parrish, R.R., 2015. Geochronology and structural setting of Latest Devonian – Early Carboniferous magmatic rocks, Cape Kiber, northeast Russia. Can. J. Earth Sci. 52, 147-160. http://dx.doi.org/10.1139/cjes-2013-0184.

Laverov, N.P., Lobkovsky, L.I., Kononov, M.V., Dobretsov, N.L., Vernikovsky, V.A., Sokolov,S.D., Shipilov, E.V., 2013. Geodynamic model of Arctic basin and adjacent territories development for Mesozoic and Cenozoic and outer boundary of Russian continental shelf.

IP T

Geotektoniks. 1, 3-35. (in Russian).

Laverov, N.P., Lobkovsky, L.I., Kononov, M.V., Dobretsov, N.L., Vernikovsky, V.A., Sokolov,

SC R

S.D., Shipilov, E.V., 2012. Basic model of Arctic tectonic evolution as a foundation for preparation of renewed application of Russia to U.N.O Commission for establishment of outer boundary of continental shelf. Arctic. 2 (6), 4-19. (in Russian).

U

Lavwer, L.A., Gahagan, L.M., Norton, J., 2011. Palaeogeographic and tectonic evolution of the

N

Arctic region during the Palaeozoic. In: Spencer, A. M., Embry, A. F., Gautier, D. L.,

A

Stoupakova, A. V. & Sørensen, K. (Ed.) Arctic Petroleum Geology. Geological Society

http:/dx.doi.org/10.1144/M35.5.

M

London, Memoirs. 35, 61–77. 0435-4052/11/$15.00 # The Geological Society of London.

ED

Letnikova, E.F., 2005. Geochemical types of the carbonate deposits within different geodynamic

PT

settings of north-eastern part of Paleoasian ocean. Lithosphere. 1, 70-81 (in Russian).

Letnikova, E.F., 2003. REE-Distribution from Different Geodynamic Types Carbonate Deposits

CC E

on the Example of Siberian South Folded Frame. Dokladi Academii Nauk Rossii. 2003. 393. 2, 235-240. (in Russian). Lobanov, M.F., 1957. Geology of Soviet Arctic. Trudy NIIGeologia Arctic. М.:

A

Gosgeoltekhizdat. 81, 504-519. (in Russian).

Lobkovsky, L.I., Verzhbitsky, V.E., Kononov, M.V., Shreider, A.A., Garagash, I.A., Sokolov, S.D., Tuchkova, M.I., Kotelkin, V.D., Vernikovsky, V.A., 2011. Geodynamic model of the evolution of the Arctic region in the Late Mesozoic - Cenozoic and the problem of the outer boundary of the continental shelf of Russia. Arktika. Ecology and economics. 1. 104-115. (in Russian).

Luchitskaya, M.V., Sokolov, S.D., Bondarenko, G.E., Katkov, S.M., 2010. Composition and Godynamic setting of the Granitiod Magmatism in the Alyarmaut Uplift Western Chukchi Peninsula. Geochemistry International. 48. 9, 891–916.

Luchitskaya, M.V., Sokolov, S.D., Katkov, S.M., Kotov, A.B., Natapov, L.M., Belousova, E.A., 2015. Late Paleozoic granitic rocks of the Chukchi Peninsula: Composition and location in the

IP T

structure of the Russian Arctic. Geotectonics. 49. 4, 243-268.

Lychagin, P. P., 1997. Volcanic associations of the South Anyui Fold Zone. In: Magmatism and

SC R

Mineralization in the Northeast of Russia .Knizhnoe Izdatel’stvo Magadan, 17–33.

Maslov, A.V., 2005. Sedimentary rocks: methods for studying and interpreting the data obtained.

U

Ekaterinburg. Ural State Mining University, 289. (in Russian).

N

Mazumdar, A., Tanaka, K., Takahashi, T., Kawabe, I., 2003. Characteristics of rare earth

A

element abundances in shallow marine continental platform carbonates of Late Neoproterozoic

M

successions from India. Geochemical Journal. 37, 277 – 289.

McLennan, S. M., 1989. Rare earth element in sedimentary rocks: Influence of provenance and

ED

sedimentary processes. In: Lipin, B. R. and McKay, G.A., (Ed.), Geochemistry and Mineralogy

PT

of Rare Earth Elements. Mineral Society of America. 21, 169–200.

Meng Y., Zneng D., Li M., 2017. Geochemistry evidence for depositional setting and

CC E

provenance of Jurassic argillaceous rocks of Jiyuan Basin, North China. J.Earth Syst. Sci, 126, 14, 1-4. http:/dx.doi.org/10.1007/s12040-016-0782-y.

Miller, E. L., G. E. Gehrels, V. Pease, and S. Sokolov, 2010. Stratigraphy and U-Pb detrital

A

zircon geochronology of Wrangel Island, Russia: Implications for Arctic paleogeography: AAPG Bulletin. 94. 5, 665–692.

Nichols, G., 2009. Sedimentology and Stratigraphy, second edition. Wiley-Blackwell, 419.

Palmer, M.R., 1985. Foraminifera tests. Earth Planet. Sci. Lett, 73, 285-298.

Parfenov, L.M., 1984. Continental Margins and Island Arcs in the Mesozoides of Northeastern Asia, Novosibirsk: Nauka, 192. (in Russian).

Parfenov, L.M., Natapov, L.M., Sokolov, S.D., Tsukanov, N.V., 1993. Terrane Analysis and Accretion in Northeast Asia, The Islands Arc. 2, 35–54.

IP T

Pettijohn, F.J., 1975. Sedimentary rocks. Harper & Row. New York, 628.

Pinard, S., Mamet, B., 1998. Taxonomie des petits foraminifẽrs du Carbonifẽre supẽrieur Permien infẽrieur du basin de Sverdrup, Arctique canadien. Palaeontographica Canadiana 15,

SC R

253.

Piper D.Z., 1974. Rare earth elements in sedimentary cycle: a summary. Chem. Geol., 14, 285-

U

304.

N

Prokoph, A., Shields-Zhou, G.A., Veizer, J., 2008. Compilation and time-series analysis of a

A

marine carbonate δ 18O, δ 13 C, 87Sr/86Sr and δ 34S database through Earth history, Earth-

M

Science Reviews. 87, 113-133.

Qi Y.-P., Lambert L.L., Nemyrovska T.I., Wang X.-D., Hu K.-Y., Wang Q.-L., 2015. Late

ED

Bashkirian and early Moscovian conodonts from the Naqing section, Luodian, Guizhou,

PT

South China // Palaeoworld. http:/dx.doi.org/10.1016/j.palwor.2015.02.005.

Reitlinger, E.A., 1975."Namurian Stage" in the stratigraphic scale of the USSR (European part).

CC E

In: Stratigraphy and biogeography of the seas and land of the Carboniferous period in the territory of the USSR. Vishcha school publishing house. Kiev State University. Kiev, 39- 49. (in Russian).

A

Rogozov, Yu.G., Vasil’eva, N.M, Solovieva, M.F., 1968. Stratigraphy and lithology of the Devonian and Carboniferous deposits of Western Chukotka (Report on the theme "Lithology and stratigraphy of Paleozoic deposits of the coast of the Chukchi Sea"). Leningrad. NIIGA funds. (in Russian).

Rogozov, Yu.G., Vasil’eva, N.M., Solovieva, M.F., 1970. Stratigraphy and lithology of the Devonian and Carboniferous deposits of Cape Kiber (Contractual thematic work with Chaunskaya RayGRU SVGU). Leningrad. NIIGA funds. (in Russian).

Sadovskii, A.I., Syrkin, P.P., Teplykh, V.I., 1962. Report on the work of the Kitep geological survey party at the scale of 1: 200 000. Seimchan settlement funds.

IP T

Sadovskii, A. I. and Gel’man, M. L., 1970. Geologic map of USSR. Directorate, Anyui– Chaunskaya series. Sheet R-58-XXVII, XXVIII: scale 1: 200000. Explanatory Report.

SC R

Leningrad. VSEGEI. (in Russian).

Samorukov, N.M., & Matveenko, V.T., 1984. Geologic map of USSR. Directorate. AnyuiskoChaunskaya series. R-59-XXIII, XXIV: scale 1:200,000, 1 sheet. Leningrad. VSEGEI. (in

U

Russian).

N

Semikhatov M.A., Kuznetsov A.B., Podkovyrov V.N., Bartley J.K., Davydov Yu.V., 2004. The

A

Yudoma group of stratotype area: C-isotope chemostratigraphic correlations and Yudomian-

M

Vendian relation // Stratigraphy and Geological correlation. 12, 5, 435-459.

Shatskii, N.S., 1935. Geology and minerals of the North of the USSR. Leningrad.

ED

Glavsevmorput’, 149-165. (in Russian).

PT

Sizykh, V. A., Ignat’ev, L. D., Shkol’nii, D. G., Berlimble, V. P., Fomin, R. S., Redyuk, and Sukhina, R. S., 1977. New data on stratigraphy and tectonics of the left-bank Malyi Anyui area.

CC E

In: Proceedings on Geology and Mineral Resources of the Northeastern USSR. Book 1. 23, 29– 34.

Sokolov, S.D., Tuchkova, M.I., Moiseev, A.V., Verzhbitsky, V.E., Malyshev, N.A., Gushina,

A

M.Yu., 2017. Tectonic zonation of Wrangel Island (Arctic). Geotectonics. 1, 3-18.

Sokolov, S.D., Tuchkova, M.I., Ganelin, A.V., Bondarenko, G.E., Layer P., 2015. Tectonics of the South Anyui Suture, Northeastern Asia. Geotectonics. 49. 1, 3-26.

Sokolov, S. D., 2010. Tectonics of Northeast Asia: An Overview. Geotectonics. 44. 6, 493-509.

Sokolov, S. D., Bondarenko, G. Ye., Morozov, O. L., Ganelin, A. V., Podgorny, I. I., 2001. Nappes tectonics of the South Anyui suture zone (western Chukotka), Dokladi Academii Nauk Rossii. 376. 1, 80-84. (in Russian).

Sokolov, S.D., Bondarenko, G.E., Tuchkova, M.I., Layer, P., 2006. Tectonic Setting and Origin of Sedimentary-Volcanic Deposits of the Polyarnyui Uplift (South Anyui Suture, West

IP T

Chukotka). Dokladi Academii Nauk Rossii. 410. 6, 784-789. (in Russian).

Solovieva M.F., 1975. Biostratigraphic based on foraminiferas Lower and Middle Carboniferous deposits of Kotel'nyui, Wrangel islands and Chukotka. In: Upper Paleozoic of USSR. Leningrad.

SC R

Nauka, 42-53. (In Russian).

Sosunov, G.M., Til’man, S.M., (Ed.) 1960: Geologic map of USSR: Directorate, AnyuiskoChaunskaya series. Sheet R-58-XXXV, XXXVI: scale 1:200,000, 1 sheet. Leningrad. VSEGEI.

N

U

(in Russian).

A

Tanaka, K., Miura, N., Asahara, Y., and Kawabe, I., 2003. Rare earth element and strontium isotopic study of seamount-type limestones in Mesozoic accretionary complex of Southern

M

Chichibu Terrane, central Japan: Implication for incorporation process of seawater REE into

ED

limestones. Geochemical Journal. 37, 163 -180. Tibilov, I.V., Cherepanova I.Yu., 2001. Geology of northern part of Chukota – modern condition

PT

and problems. Мoscow. GEOS, 94. (in Russian).

CC E

Til’man, S.M., Byalobzhesky, S.G., Chekhov, A.D., 1964. Geological Structure of Wrangel Island. In:Trudy SVKNII. Magadan. 11, pp. 53-97. (in Russian).

Tkachenko, B.V., Yegiazarov B.Kh., 1970. Geology of the USSR, Islands of Soviet Arctic.

A

USSR. Geology. XXVI. Moscow. Nedra, 548. (in Russian).

Trettin H.P., 1991. Late Silurian-Early Devonian deformation, metamorphism, and granitic plutonism, Northern Ellesmere and Axel Heiberg islands. Trettin H.P. (ed.). Geology of the Innuitian orogeny and Arctic platform of Canada and Greenland. Geol. Surv. Canada. Geology of Canada. 3. 295–309.

Ustritskii, V. I., 1975. Geological history of the Arctic Region in Paleozoic Time. In: Upper Paleozoic of North-East of USSR. NIIGA. Leningrad, pp. 54–75. (In Russian). Vasil’eva, N.M., Rogozov, Yu.G., Solovieva, M.F., 1974. Stratigraphy of Devonian deposits of Chukotka and Wrangel Island. In: Precambrian and Paleozoic of USSR North-East. Abstracts of inter-departmental stratigraphical conference. Magadan, 88-89. (in Russian).

IP T

Veizer, J., Ala, D., Azmy, K., Bruckschen, P., Buhl, D., Bruhn, F., Carden, G.A.F., Diener, A., Ebneth, S., Godderis, Y., Jasper, T., Korte, C., Pawellek, F., Podlaha, O.G., Strauss, H.,

SC R

1999. Chemical Geology. 161, 59-88.

Vernikovsky, V. A., Metelkin, D. V., Vernikovskaya, A. E., Matushkin, N. Yu., Lobkovsky, L.I., Shipilov, E. V., 2011. Early evolution stages of the arctic margins (Neoproterozoic-Paleozoic) and plate reconstructions. ICAM VI: Proceedings of the International Conference on Arctic

U

Margins VI. Fairbanks. Alaska. Published by: A.P. Karpinsky Russian Geological Research

A

N

Institute (VSEGEI). Copyright 2014. VSEGEI, 265-285.

Vernikovsky, V.A., Vernikovskaya, A.E., 2001. Central Taymyr accretionary belt (Arctic Asia):

M

Meso-Neoproterizoic tectonic evolution and Rodinia breakup. Precambrian Research.

ED

110, 127-141.

Vernikovsky ,V. A., 1996. Geodynamic Evolution of the Taimyr Fold Region. OIGGM.

PT

Novosibirsk, 202. (in Russian).

CC E

Verzhbitsky, V. E., Sokolov, S. D., Tuchkova, M. I., 2015. Present-day structure and stages of tectonic evolution of Wrangel Island, the Russian Eastern Arctic region. Geotectonics. 49, 165–192.

A

Verzhbitsky, V. E., Malysheva, S.V., Sokolov, S.D., Tuchkova, M.I., Khafizov, S.F., 2012. Problems of tectonics and hydrocarbon potential of Russian sector of Chukchi Sea. Neftyanoe khozyastvo. Geologia and geologo-razvedochnye raboty. 8, 8-13. (in Russian).

Vinogradov, A.P., Nalivkin, V.D., Posner, V.V. Eds. 1969. Atlas of lithologic-paleogeographic maps of the USSR. Volume II. Devonian, Carboniferous and Permian periods, scale 1 7 500 000. 2. Aerogeological Trust. Moscow.

Wang, A.H., 1996. Discriminant effect of sedimentary environment by the Sr/Ba ratio of different existing forms, Acta Sedimentol Sin 14, 168–173.

Webb, G.E., Kamber, B.S., 2000. Rare earth elements in Holocene reefal microbialites: A new shallow seawater proxy. Geochimica et Cosmochimica Acta. 64. 9, 1557–1565.

IP T

Yegorov, D. F., 1962. Geologic map of USSR. Directorate, Anyuiskoe Gosudarstvennoe GornoGeologicheskoe Predpriyatie, report. Sheet Q-58-V-VI, between the Anyui and Chaun

SC R

Rivers: scale 1:200 000. Leningrad. VSEGEI. (in Russian).

Yegorov, D.F., Afitskii, A.I., 1957. Stratigraphy of the eastern part of the Anyuisk folded zone and the Lyupveem River basin (Summary report on the work of the Malo-Anyui

U

stratigraphic party for 1956). (in Russian).

N

Zonenshain L.P., Kuz’min M.I., Natapov L.M. Tectonics of lithospheric plates of USSR

A

territory. Book 1. М.: Nedra, 1990. 328. (in Russian).

M

Zonenshain, L.P., Natapov, L.M., 1987. Tectonic history of Arctic. In: Actual problems of

A

CC E

PT

ED

oceans and continents tectonics. Мoscow. Nauka, pp.31–57. (in Russian).

Figure captions Fig. 1. Map of schematic tectonic structure of Northeastern Russia (after Sokolov et al., 2010) and location of young uplifts within which Paleozoic carbonate rocks are exposed, and box showing location of Figure 1.1: New Siberian-Wrangel Fold Belt, Wrangel Island, 2: Anyui-Chukotka Fold Belt: An Anyui subterrane, Ch Chaun subterrane, 3: South Anyui Fold Belt, 4: Kolyma Loop, 5: Okhotsk-Chukotka volcanic belt, 6: Location of Paleozoic limestone sequences.

A

CC E

PT

ED

M

A

N

U

SC R

Wrangel Island, 2: Kuul Uplift, 3: Alyarmaut Uplift, 4: Polyarnyui Uplift.

IP T

Numbers on the map show locations of the studied Paleozoic carbonate rocks: 1:

Fig. 2. Simplified geological map of the Arctic, modified from the Geological Map of the Geological Survey of Canada, (2008) with areas of detailed maps seen in figs. 4-6 and

A

CC E

PT

ED

M

A

N

U

SC R

IP T

8-10 shown in boxes. Legend is used in figs 4-6 and 8-10.

Fig. 3. Correlation between sections of Carboniferous carbonates from Wrangel Island and the Chukotka region and faunal data: published (black text) and new, this paper

A

CC E

PT

ED

M

A

N

U

SC R

IP T

(red text). The legend will be used in Figures 4-11.

Fig.4. Geological map of Wrangel Island, after Kos’ko et al., (2003), legend for map is in

A

CC E

PT

ED

M

A

N

U

SC R

IP T

fig. 2.

Fig.5. Sections of carbonate sequence of Wrangel Island, Central Tectonic Zone. A: Lithology and location of sample points, legend in fig. 3; on the left side of the lithologic column are the units (black text) and sub-units (red text); sample numbers in red on the right side of the column; B: Outcrop/hand sample photos, sample location is shown by big red point: Sub-unit 1, sample 700/4 - intercalation of white silty limestone and gray cherts; Sub-unit 3, sample 705/3 - limestone and white beds of evaporite; Sub-unit 5, sample 496/2 – limestone alternating with massive sandy limestone, sample 706/2 –

IP T

clastic and bioclastic limestone, contains diverse fossils and algae, sample 656/1 –

A

CC E

PT

ED

M

A

N

U

SC R

bioclastic imestone with faunal fragments.

Fig. 6. Sections of carbonate sequence of Wrangel Island, Southern Tectonic Zone. A: Lithology and location of sample points, legend in fig. 3; on the left side of the lithologic column are the units (black text) and sub-units (red text); sample numbers in red on the right side of the column; B: Outcrop/hand sample photos, sample location is shown by big red point: Sub-unit 2, sample 601/11-1 - beds of grey chert in reddish limestone, Somnitel'naya river, Unit C1-C2, sample 720/1 – limestone with variously colored chert, Uering Cape (the Uering Formation, after Ganelin et al., 1989), sub-unit 5, sample

IP T

492/22 – beds of limestone and lime mudstone with bioturbation and vertical worm trail, Ptichii Bazar Cape, sample 610/1 - desiccation crack on the top of sandy limestone bed,

Khishchnikiv River; Sub-unit 6, sample 492/24, deformed fragment of unit, presented by

SC R

limestone intercalated with dolomitic limestone and sandy limestone with lime

mudstone, color of rocks are grey, dark grey and brown, Ptichii Bazar Cape, sample

A

CC E

PT

ED

M

A

N

U

616/1 - intercalated dolostone (reddish) and limestone (gray) beds, Khishchnikov River.

Fig. 7. Thin-sections of typical samples of carbonate units of Wrangel Island. In the left: Southern Tectonic zone. Sub-unit 1, sample 602/8 – sub-rounded quartz and metamorphic rocks with muddy and limy matrix, there are dissolution effect; Sub-unit 2, sample 601/11-1 – mudstone and lime mudstone with stylolithe, related to overbuden loading. Note the equant uniform cristals; Sub-unit 4, sample 605/3 – thin-section of evaporite bed in limestone unit, small grains of gypsum, calcite and anhydrite with aggregates of piryte; Sub-unit 5, sample 612/4 – limestone with rare rounded quartz

IP T

grains, there are cleavage with organic matter; Sub-unit 6, sample 732/2 – clastic muddy limestone with fragments of fauna and lithoclasts of mudstone; Sub-unit 6,

sample 614/1.– biclastic limestone with fragments of fauna and lithoclast of quartz. All

SC R

clasts are overgrowth by selectively original material (quartz by quartz, fauna by calcite). In the right: Central Tectonic zone, Sub-unit 1, sample 700/4 – Organic-rich, silty limstone with scattered fine-sand grains, organic matter is along cleavage; Sub-unit 3, sample 705/3 – gypsum and calcite cemented by compact calcite, there are dissolution

U

of all grains; Sub-unit 4, sample 649/1 – Coarse-grained quatzite with calcite and

N

dolomite cement. Quartz grains are manifest dissolution effect, essentially between

A

quartz grains; Sub-unit 5, sample 706/1 – bioclastic limestone with fragment of corals, intersceletal pore are filled with calcite cement.

A

CC E

PT

ED

M

On the microphotos: Qtz – quartz, Dol – dolomite, Gyp – gypsum, Ca – calcite.

Fig. 8. Carboniferous corals from the Wrangell Island. 1-3: Bothroclisia aff. clisiophylloides Fomichev. Specimen 732/2, oblique transverse section, , 1-x3, 2x2,5; 3 x3. V’uchnyi Kreek, Moscovian Stage N 71o02.043; W 179o41.963; 4 - Paracherichioides? cf. kosvensis (Gorsky) Specimen 601-9 x2. Khischnikov River, Bashkirian stage; 5-9: Caninella koscharowi (Stuckenberg). Specimen 735-2/2, 5 x 4; 6-7 x 2,5;8x2; 9- longitudinal section x 2; V’uchnyi Kreek, Moscovian Stage (probably upper part). The species also occurs in Kasimovian, N 71o01.418; W 179o40.853; 10-11: Paracherichioides sp. Specimen 706-07, Krasnyi Flag River,

IP T

Bashkirian –Moscovian. Scale bar 2 mm. N 71o15.764; W 178o48.475; 12-13: Skolecophyllum sp., Specimen 504-1, 12 x4, 13x2, Somnitelnaya River. The encrustations of cyanobacterial calciteprismatic layer are visible around the transverse section of corals. The genus is known

A

CC E

PT

ED

M

A

N

U

SC R

from the Moscovian of Donetz Basin;

Fig 9. Foraminifera, samples of Wrangel Island, Plate 1, the scale ruler is 0.1 mm for 1-4, for all others – 1 mm. 1 – 4: Lateenoglobivalvulina spiralis (Morozova). Sample. 732/02; 5: Neostaffella aff. porrecta Rumjanzeva, sample 706/1; 6-7: Eowaeringella aff. castigata Solovieva, sample 701-1; 8-15: Eowaeringella ex gr. lata (Thompson), sample701-1; 16,17: ?Kanmeraia sp., sample 701-1; 1 oblique lateral section; 2 and 3 axial saggittal sections; 4 lateral section; 5-7, 9, 12 – axial

A

CC E

PT

ED

M

A

N

U

SC R

IP T

sections; 8, 10, 11, 13, 16, 17 – paraxial sections, 14, 15 median sections.

Fig 10. Fusulinides , samples of Wrangel Island, Plate 2, Scale ruler 1 mm. 1, 2, 3: Kanmeraia aff. pseudozelleri Solovieva, sample 701-1; 4, 5, 6: ?Kanmeraia sp., sample

A

CC E

PT

ED

M

A

N

U

SC R

IP T

701-1; 7: ? Eowaeringella sp., sample 701-1; 8-17: Eowaeringella sp., sample 701-1.

Fig. 11. Sections of carbonate sequence of Kuul Uplift, near Kibera Cape. A: Geological map (after Samorukov, Matveenko, 1984), legend for map in fig. 2; B: Lithology and location of sample points, legend in fig. 3; on the left side of the lithological column are the units (black text) and sub-units (red text); sample numbers in red on the right side of the column; C: Outcrop/hand sample photos, sample location is shown by big red point: Sub-unit 2, sample M10/10-2 – rhythmic intercalation of grey and dark grey limestone with quartz grains; Sub-unit 3, sample M10/17-2 – alternating grey and reddish

IP T

limestone; Sub-unit 3, sample M10/20-4, limestone gravel with graded bedding and

A

CC E

PT

ED

M

A

N

U

SC R

faunal debris at the bottom of the layer.

Fig. 12. Sections of carbonate sequence of Alyarmaut Uplift, Lyupveem River, Prokhladnyi and Yagelnyi Creeks. A: Geological map (after Belik, Sosunov, 1969; Sadovskii, Gel’man, 1970), legend for map in fig. 2; B: Relations between the Paleozoic and overlying Triassic formation in the Lyupveem River (photo by M.Tuchkova); C: Lithology and location of sample points, legend in fig. 3; on the left of the lithological column are the units (black text) and sub-units (red text); sample numbers in red on the right side of the column; D: Breccia in the lower part of carbonate section in Prokhladnyi

IP T

Creek; E: Cross-section from granite batholith to Triassic formation (after Bondarenko, 2004); F: Outcrop/hand sample photos: Sub-unit 3, lower part, sample 458/2,

intercalation of white grey and dark grey limestone; Sub-unit 3, sample 458/7 – grey and

SC R

white grey limestone with lenses and beds of grey chert; Sub-unit 4, sample 458/8 –

A

CC E

PT

ED

M

A

N

U

white limestone from the top of the sequence.

Fig. 13. Sections of carbonate sequence of Polyarnyui Uplift, Polyarnyui Creek. A: Geological map (after Yegorov, 1962), legend for map in fig. 2; B: Lithology and location of sample points, legend in fig. 3; on the left of the lithological column are the names of units (black text); sample numbers in red on the right side of the column; C: Crosssections, modified after Sokolov et al., 2006, legend in fig 3; D: Photos of samples: (a) breccia in the lower part of carbonate section, photo by Bondarenko G.E.; (b): Sample 202/1, pebbles of limestone in limonitic cement; (c) Sample 202/3, white clastic

A

CC E

PT

ED

M

A

N

U

SC R

IP T

grainstone with limonite in the cement

Fig. 14. Thin-sections of typical samples of carbonate units of Polyarnyui, Alyarmaut and Kuul Uplifts. In the left: Thin-sections of Polyarnyui Uplift, sample 202/3 – clastic limestone with rare fragments of limestone with fauna, there are different generation of stylolithe oriented in different ways; sample 003/2 – clastic limestone with pores filled by cataclastic calcite. Fragments of limestones are rounded and overgrowth by calcite. In the middle: Thin-sections of Alyarmaut Uplift: Sub-unit 1, sample 406/7 – limestone

IP T

with rare silty (no more than 0.1 mm) rounded quartz grains, there are cleavage with organic matter along cleavage; Sub-unit 2, sample 458/7 – calcarenite ; Sub-unit 3,

sample 406/1 – calcarenite with local silicification, no terrigenous admixture occurs in

SC R

these beds; Sub-unit 4, sample 458/8 –. calcarenite with quartz grains.

In the right: Thin-sections of Kuul Uplift: Sub-unit 1, sample M10/9-1 – cement of coarse-grained polymictic conglomerate. Lithoclasts presented by quartz, feldspar, shist, quartz are rounded and not rounded, feldspar and shist not rounded. All lithoclasts

U

are cemented by calcite; Sub-unit 2, sample M10/10-2 – calcarenite with quartz grains

N

and lithoclasts of limestone, schist and shale. All lithoclasts are overgrowth by calcite;

A

Sub-unit 3, sample M10/17-2 – mudstone with homogenous texture of micrite; Sub-unit 3, sample M10/20-4 – calcarenite with fragments of fauna, grains of quartz and calcite

A

CC E

PT

ED

M

and lithoclasts of muddy limestone. All lithoclasts are overgrowth by calcite.

Fig. 15. Distribution of geochemical parameters: salinity (Sr/Ba ratio); distinction of felsic and basic rock sources (Co/Th ratio), and isotopes δ13С and δ18O in sequences of Paleozoic carbonate: A: Wrangel Island, Central Tectonic Zone; B: Wrangel Island,

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Southern Tectonic Zone; C: Kuul Uplift; D: Alyarmaut Uplift; E: Polyarnyui Uplift.

Fig. 16. C1 Chondrite-normalized REE abundance patterns for Carboniferous limestone samples compared with Post Archean Average Shale (PAAS), A: Mississippian samples, B: Pennsylvanian samples; C: (Y/Ho) vs (Y/Yb) plot for Carboniferous limestone samples; D: (Co/Th) vs (La/Sc) plot, showing different provenances for clastic rocks: I – erosion of rocks close in composition to average upper continental crust – granodiorite composition, II – increasing influence of mafic rocks erosion, III – increasing influence of felsic rocks erosion; E: HREE-LREE plot for Carboniferous

A

CC E

PT

ED

M

A

N

U

SC R

IP T

samples of limestone showing different environments of carbonate sedimentation.

Fig.17. Palaeogeographic maps of Chukotka and the Wrangel Island region for the

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Mississippian (A) and the Pennsylvanian (B) time.

Fig.18. Correlation between sedimentologic, stratigraphic and tectonic events in the

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Chukotka and the Wrangel Island region during the Carboniferous Time.

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Table 1. Foraminifera, samples of Wrangel Island, Plate 1, the scale ruler is 0.1 mm for Figs 1-4, for all others – 1 mm.

Figs.1 – 4: Lateenoglobivalvulina spiralis (Morozova). Sample. 732/02, Fig. 5: Neostaffella aff. porrecta Rumjanzeva, sample 706/1, Figs. 6-7: Eowaeringella aff. castigata Solovieva, sample 701-1; Figs. 8-15: Eowaeringella ex gr. lata (Thompson), sample701-1; Figs 16,17: ?Kanmeraia sp., sample 701-1. Fig.1

oblique lateral section; Fig. 2 and 3 axial saggittal sections; Fig. 4 lateral section; Figs. 5-7, 9, 12 – axial sections; Figs. 8, 10, 11, 13, 16, 17 – paraxial sections, Figs. 14, 15 median sections.

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Table 1 (continuation) Fusulinides , samples of Wrangel Island, Plate 2, Scale ruler 1 mm.

Figs 1, 2, 3: Kanmeraia aff. pseudozelleri Solovieva, sample 701-1; Figs. 4, 5, 6: ?Kanmeraia sp., sample 701-1; Fig. 7: ? Eowaeringella sp., sample 701-1; Figs 8-17: Eowaeringella sp., sample 701-1.

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Table 2 Carboniferous corals from the Wrangell Island.

Figs. 1-3: Bothroclisia aff. clisiophylloides Fomichev. Specimen 732/2, oblique transverse section, , 1-x3, 2x2,5; 3 x3. V’uchnyi Kreek, Moscovian Stage N 71o02.043; W 179o41.963

4 - Paracherichioides? cf. kosvensis (Gorsky) Specimen 601-9 x2. Khischnikov River, Bashkirian stage. Figs. 5-9: Caninella koscharowi (Stuckenberg). Specimen 735-2/2, 5 x 4; 6-7 x 2,5;8x2; 9- longitudinal section x 2; V’uchnyi Kreek, Moscovian Stage (probably upper part). The species also occurs in Kasimovian, N 71o01.418; W 179o40.853. Figs. 10-11: Paracherichioides sp. Specimen 706-07, Krasnyi Flag River, Bashkirian –Moscovian. Scale bar 2 mm. N 71o15.764; W 178o48.475

A

CC E

PT

ED

M

A

N

U

SC R

IP T

Figs. 12-13: Skolecophyllum sp., Specimen 504-1, 12 x4, 13x2, Somnitelnaya River. The encrustations of cyanobacterial calciteprismatic layer are visible around the transverse section of corals. The genus is known from the Moscovian of Donetz Basin.

Table 3. Contents of carbonates and non-carbonate minerals by XRD*

Sample

Location

Minerals

701/3

(1-1c) Wrangel Island, Central Tectonic Zone, Krasnyi Flag R., Unit C2, Moscovian

705/2

(1-1b) Wrangel Island, Central Tectonic Zone, Calcite, Dolomite, Gypsum, Quartz Krasnyi Flag R., Unit C1, Tournaisian-Visean

287/2

(1-1b) Wrangel Island, Central Tectonic Zone, Calcite, Quartz, Dolomite Krasnyi Flag R., Unit C1, Tournaisian-Visean

705/3

(1-1b) Wrangel Island, Central Tectonic Zone, Calcite, Quartz, Dolomite Krasnyi Flag R., Unit C1, Tournaisian-Visean

494/4-2

(1-1b) Wrangel Island, Central Tectonic Zone, Calcite, Quartz Neizvestnaya R., Unit D3-C1, TournaisianVisean

496/2

(1-1c) Wrangel Island, Central Tectonic Zone, Neizvestnaya R., Unit C2, Bashkirian

496/4

(1-1c) Wrangel Island, Central Tectonic Zone, Neizvestnaya R., Unit C2, Bashkirian

Dolomite, Calcite, Quartz, Muscovite

709/4

(1-2a) Wrangel Island, Southern Tectonic Zone, C.Uering, Unit D-C1

Quartz, Gypsum, Chamosite, Zeolite

720/2

(1-2b) Wrangel Island, Southern Tectonic Zone, C.Uering, Unit C1-2

Quartz, Muscovite

IP T

SC R

U

N

A

M

ED

PT

(1-2a) Wrangel Island, Southern Tectonic Zone,Khishnikov R., Unit D-C1

CC E

490/5

Calcite, Quartz

Mg-Calcite, Calcite, Graphite

Quartz, Ankerite, Clinochlore, Muscovite

(2a) Kuul Uplift, Kibera Cape, Yunona Fm., Tournaisian-Serpoukhovian

Ankerite,Quartz, Clinochlore, Carlinite, Anorthoclase

M10/17-2

(2b) Kuul Uplift, Kibera Cape, Kibera Fm., Moscovian

Illite, Quartz, Dolomite, Muscovite

M10/20-3

(2b) Kuul Uplift, Kibera Cape, Kibera Fm., Moscovian

Calcite, Ankerite, Quartz, Muscovite

M10/20-4

(2b) Kuul Uplift, Kibera Cape, Kibera Fm., Moscovian

Calcite, Quartz

458/4

(3) Alarmaut Uplift, Visean

Mg-Calcite, Quartz

A

M10/11-1

458/6

(3) Alarmaut Uplift, Visean

Dolomite, Mg-Calcite

458/8

(3) Alarmaut Uplift, Visean

Mg-Calcite, Dolomite

459/8

(3) Alarmaut Uplift, Yagelny Stream, Visean?Serpoukhovian?

Mg-Calcite, Dolomite, Quartz

003/2a

(4) Polarny Uplift, Visean

Calcite, Quartz

003/2b

(4) Polarny Uplift, Visean

Calcite, Graphite, Quartz

A

CC E

PT

ED

M

A

N

U

SC R

IP T

* the composition of minerals is presented by the decreasing amount of minerals.

I N U SC R

Table 4

Rare earth element composition of samples from Chukotka region (Mississippian) Mississippian

(1-1) Wrangel Island, Central Tectonic Zone

Object

(3) Alarmaut Uplift

(4) Polarnyui Uplift

612/4

612/7

721/2

501/6

М 10/11-1

458/7

458/2

003/2б

202/1

202/3

6

7

8

9

10

14

15

16

17

18

19

19,6

5,2

0,49

5,8

40,9

29,0

1,1

4,1

0,29

0,23

0,28

0,67

0,86

0,29

0,08

0,60

0,67

1,3

0,021

0,084

0,036

0,067

0,062

1,8

3,0

6,0

1,8

0,43

2,6

5,3

7,1

7,7

0,15

0,43

0,58

0,53

0,73

10,8

45,2

70,5

13,5

3,3

21,7

40,8

49,2

41,6

3,8

5,1

4,4

2,7

3,4

700/4

700/5

705/1

697/1

697/2

Element

1

2

3

4

5

Li

3,6

2,5

5,3

7,0

Be

0,44

0,28

0,13

Sc

2,8

1,9

V

33,8

20,1

Cr

29,0

Co

2,1

M

ED

PT

715/1

A

Sample

21,2

5,9

30,5

52,4

12,0

2,3

10,1

32,2

68,2

39,0

2,3

6,6

5,2

4,8

7,3

2,0

3,2

2,8

4,3

2,0

1,1

3,8

4,3

12,6

5,5

0,55

0,76

0,76

< bdl

< bdl

38,4

19,3

8,9

13,0

7,7

8,0

9,2

CC E

Ni

(2) Kibera Cape

(1-2) Wrangel Island, Southern Tectonic Zone

22,6

26,6

28,9

29,8

39,4

8,9

4,2

29,3

33,9

10,3

10,7

3,6

14,2

22,4

3,5

3,5

28,2

15,3

10,8

1,5

1,6

4,7

1,5

1,8

45,2

36,7

13,5

43,6

54,0

20,7

23,6

36,1

71,1

89,4

14,6

108

4,7

7,0

10,6

Ga

2,5

1,1

1,5

2,7

5,9

1,6

0,21

7,5

5,7

8,7

0,10

0,35

0,36

0,14

0,18

As

5,6

26,7

0,0

6,1

2,0

0,0

0,0

5,5

0,0

0,74

< bdl

0,89

4,4

4,0

1,5

Se

<2

< 1,6

0,0

<2

<3

0,0

0,0

0,0

< 0,9

< bdl

< bdl

< bdl

< bdl

<0,8

< bdl

Rb

7,0

5,0

0,65

13,5

38,1

13,9

1,4

19,2

26,5

37,9

81,0

0,31

1,1

2,0

0,90

0,47

Sr

474

482

335

723

820

57,6

390

507

71,9

68,4

210

116

141

212

173

138

Y

15,0

11,5

13,5

10,7

17,4

9,9

7,7

19,6

18,3

16,2

15,9

3,0

3,4

11,8

10,2

7,5

Cu

A

Zn

I 14,3

2,9

22,1

46,2

Nb

1,6

0,89

0,27

2,0

4,0

Mo

1,3

0,70

0,17

2,4

2,2

Rh

0,00

0,00

0,00

0,00

0,00

Pd

0,00

0,00

0,00

0,00

0,00

Ag

0,19

0,20

0,00

0,36

0,42

Cd

0,35

0,36

0,35

0,38

0,36

Sn*

0,38

0,24

0,00

0,53

Sb

0,35

0,62

0,10

Te

0,0

0,0

Cs

0,58

0,42

Ba

560

La

12,3

14,6

1,6

10,6

28,6

187,0

36,6

2,4

3,0

3,2

2,1

1,7

1,3

0,16

1,2

2,9

8,2

3,6

0,19

0,28

0,18

0,10

0,075

0,74

0,00

0,27

0,0

0,059

0,052

0,85

< bdl

< bdl

< bdl

0,00

0,00

0,0

0,00

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,00

0,00

0,0

0,00

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,05

0,00

0,00

0,037

< bdl

< bdl

0,071

0,047

< BDL

< bdl

0,19

0,12

0,24

0,78

0,83

0,22

0,69

0,074

0,18

0,26

0,79

0,22

0,14

0,07

0,73

1,7

< bdl

1,7

< bdl

0,49

0,13

0,71

0,49

0,35

0,48

0,29

0,35

0,50

0,13

0,14

0,23

0,79

0,23

0,0

0,0

0,0

0,0

0,0

0,0

0,0

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,048

0,89

2,7

0,64

0,14

1,2

3,2

2,6

4,4

0,04

0,17

0,10

0,044

0,033

M

ED

PT 221

2110

432

1415

152

19,7

130

257

438

515

9

16

16,4

15,0

9,2

11,3

5,4

10,3

20,5

5,9

4,2

11,0

20,1

19,1

20,8

1,1

2,5

1,8

2,2

2,1

CC E

Ce

N U SC R

20,0

A

Zr

12,4

8,8

3,7

11,0

24,3

7,8

6,6

21,2

22,3

39,7

43,4

0,88

2,4

1,2

0,80

0,76

2,4

2,0

1,1

2,0

3,8

1,3

0,80

2,5

4,1

4,7

4,9

0,15

0,38

0,32

0,39

0,32

10,1

8,2

4,6

8,0

15,2

4,9

3,1

10,3

16,6

18,7

19,5

0,65

1,5

1,5

2,0

1,6

Sm

1,8

1,4

1,1

1,5

2,9

1,0

0,67

2,5

3,2

4,0

3,7

0,12

0,26

0,34

0,42

0,28

Eu

0,4

0,57

0,19

0,32

0,81

0,22

0,24

0,58

0,7

0,88

0,79

0,028

0,062

0,11

0,12

0,082

Gd

2,1

1,6

1,4

1,5

2,8

1,2

0,80

3,1

3,0

3,5

3,3

0,15

0,30

0,60

0,62

0,39

Tb

0,30

0,21

0,22

0,23

0,42

0,18

0,12

0,51

0,44

0,51

0,47

0,026

0,043

0,090

0,10

0,063

Dy

1,7

1,3

1,3

1,4

2,4

1,1

0,70

2,7

2,6

2,83

2,5

0,15

0,26

0,67

0,72

0,46

Ho

0,36

0,28

0,28

0,30

0,52

0,24

0,17

0,51

0,53

0,53

0,48

0,036

0,059

0,17

0,174

0,11

Pr

A

Nd

I 0,83

0,86

0,9

1,6

Tm

0,14

0,11

0,11

0,12

0,22

Yb

0,93

0,74

0,70

0,8

1,5

Lu

0,14

0,11

0,11

0,12

0,22

Hf

0,45

0,29

0,11

0,6

1,4

Ta

0,10

0,053

0,001

0,13

0,26

W

0,21

0,13

0,061

0,3

0,5

Re

< 0,008

< 0,008

0,0

0,018

Ir

0,00

0,00

0,00

Pt

0,0010

0,0010

Au

0,00

0,00

Hg

-

Tl

0,092

0,72

0,49

1,4

1,5

1,6

1,4

0,12

0,19

0,54

0,57

0,36

0,090

0,060

0,16

0,20

0,24

0,20

0,016

0,022

0,077

0,071

0,050

0,60

0,35

0,92

1,4

1,3

1,3

0,093

0,14

0,42

0,47

0,31

0,092

0,048

0,12

0,19

0,23

0,20

0,015

0,022

0,070

0,068

0,044

0,45

0,24

0,4

1,1

4,8

1,1

0,11

0,066

0,066

0,043

0,041

0,048

0,008

0,070

0,30

0,54

0,34

0,12

0,089

0,13

< bdl

< bdl

0,23

0,044

0,23

0,39

1,4

0,97

0,46

0,53

0,15

0,076

0,015

0,0

0,0

0,0

0,0

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,00

0,00

0,00

0,00

0,00

0,00

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,00

0,0010

0,0010

0,00

0,0010

0,00

0,0010

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

0,00

0,00

0,00

0,00

0,00

0,00

0,00

< bdl

< bdl

< bdl

< bdl

< bdl

< bdl

M

ED

PT -

-

-

-

-

-

-

-

-

-

-

-

-

-

0,092

0,008

0,24

0,27

0,076

0,012

0,10

0,17

0,50

0,0037

0,020

0,011

< bdl

0,009

17,0

1,9

5,2

0,91

0,49

0,38

0,68

< bdl

0,049

< bdl

< bdl

< bdl

CC E

Pb

N U SC R

1,1

A

Er

2,7

2,1

0,77

3,7

5,8

2,4

1,8

2,8

2,8

0,064

0,024

0,00

0,043

0,081

0,021

0,018

0,034

0,083

1,5

0,71

0,29

1,8

3,443

1,1

0,26

1,2

4,6

5,5

5,3

0,09

0,19

0,029

0,020

0,017

1,5

1,7

1,1

2,2

1,5

0,71

0,50

1,0

1,0

1,2

0,57

0,39

1,1

0,13

0,20

0,22

LREE/HREE

9,0096

9,52

4,91

9,096

10,19

7,46

8,412

8,075

10,33

12,59

14,62

6,85

10,17

2,906972

3,004

3,93

Sr/Ba

0,847

2,18

0,16

1,67

0,58

0,38

19,81

3,89

0,28

0,16

0,41

13,11

8,79

12,92

11,553

15,09

U/Zr

0,073

0,118

0,4

0,10

0,033

0,049

0,305

0,092

0,035

0,006

0,0162

0,16

0,37

0,04

0,095

0,128

Co/Th

1,410

2,86

10,93

1,52

1,24

1,845

4,40

3,14

0,93

2,31

1,052

6,38

4,01

26,29

Mn/Sr

0,00008

0,00006

0,00002

0,00002

Bi

A

Th U

0,00054

5,5

I N U SC R

Table 4 (Continuation) Rare earth element composition of samples from Chukotka region (Pennsylvanian) Pennsylvanian

Element

20

21

22

Li

0,0

0,28

0,25

0,08

0,033

1,4

1,6

V

0,0

10,7

Cr Co Ni

23

606/1

605/7

24

607/1

616/1

735/1

614/1

25

26

27

28

29

Kibera Cape 492/231

492/23

30

31

500/2

32

М 10/172

М 10/13

33

34

35

M 10-20/8

69,4

13,0

2,5

4,8

1,6

3,6

2,2

33,1

41,8

0,87

0,60

2,8

0,28

0,4

0,1

0,25

0,82

3,0

1,4

0,23

0,0

0,90

14,5

1,9

2,3

0,8

1,0

1,8

12,6

18,9

16,2

15,0

10,0

0,47

1,1

3,8

110

13,0

24,8

3,0

15,1

9,9

81,4

117,0

145,0

90,2

64,2

< bdl

CC E

Sc

649/2

PT

Be

2,8

3,4

13,8

10,3

73,9

14,0

6,2

2,8

14,4

6,9

79,1

101,0

117,0

76,0

67,5

2,4

3,1

3,4

0,22

1,1

5,6

3,0

6,6

1,6

1,4

3,8

11,5

21,0

6,8

11,2

9,4

< bdl

30,5

32,2

8,7

7,9

15,9

20,1

30,3

8,6

8,9

17,7

39,5

51,2

68,2

39,4

40,8

6,4

A

0,13

701/1

A

706/4

M

706/ 2

Sample

(2) Kuul Uplift,

(1-2) Wrangel Island, Southern Tectonic Zone

ED

Point

(1-1) Wrangel Island, Central Tectonic Zone

Cu

2,5

3,5

1,1

6,4

4,1

6,0

7,2

1,9

1,8

3,0

7,3

9,2

1,2

Zn

11,6

16,0

3,2

36,7

18,2

7,0

11,8

14,3

37,4

4,0

120

80,0

35,2

Ga

0,21

0,43

0,0

2,8

19,8

1,3

1,6

0,5

1,1

9,9

17,2

12,9

0,17

As

0,0

4,2

0,0

2,9

1,2

5,1

1,6

4,7

1,4

11,8

10,0

5,8

2,8

Se

0,0

0,0

0,0

0,0

<1

< 1.2

0,0

0,0

< 0.7

0,0

< bdl

< bdl

< bdl

Rb

0,17

0,36

0,41

32,7

188,2

8,8

13,1

1,5

5,8

2,1

172

70,8

1,6

99,9

151,0

155,0

I 68,3

193

711

Y

1,6

1,9

1,8

3,4

16,0

9,5

Zr

0,0

1,3

0,51

7,3

78,4

8,7

Nb

0,087

0,10

0,00

0,87

10,5

1,1

Mo

0,00

0,0

0,00

0,00

0,0

1,0

Rh

0,00

0,0

0,00

0,00

0,00

0,00

Pd

0,00

0,0

0,00

0,00

0,00

Ag

0,00

0,0

0,00

0,18

0,00

Cd

0,99

1,5

0,22

0,65

Sn*

0,00

0,00

0,13

Sb

0,07

0,13

0,08

Te

0,0

0,0

Cs

0,018

0,013

361

662

89,0

22,6

42,6

103

31,9

188

12,3

13,8

4,7

13,0

31,0

34,4

27,4

14,1

7,2

8,7

17,1

7,3

12,4

3,8

209,0

216,0

239,0

77,4

64,3

1,3

1,5

0,48

1,0

0,42

16,5

20,2

18,8

8,5

7,4

0,072

0,52

0,34

0,47

5,2

0,13

0,078

< bdl

0,00

0,00

0,00

0,0

< bdl

< bdl

< bdl

0,00

0,00

0,00

0,00

0,0

< bdl

< bdl

< bdl

0,00

0,001

0,001

0,00

0,00

< bdl

< bdl

< bdl

0,00

0,042

0,001

0,19

0,43

0,043

0,34

0,060

0,81

0,45

2,8

0,26

0,12

0,00

0,23

0,00

2,7

1,5

0,18

2,55

0,49

0,33

0,49

0,39

0,34

1,5

15,0

0,93

0,46

< bdl

< bdl

< bdl

PT 0,0

0,0

0,0

0,0

0,0

0,0

0,0

0,05

1,3

12,8

0,76

1,0

0,10

0,63

0,14

8,9

14,2

11,7

9,1

4,9

0,15

6,8

3,9

8,4

137

474

44

39,0

49,7

68,8

27,5

1240

1530

1380

875

288

18,1

0,41

0,75

0,56

2,1

40,5

9,6

4,0

6,3

5,8

6,4

36,7

44,4

47,3

28,9

18,2

4,6

0,46

0,65

0,26

6,2

85,3

16,7

7,9

6,1

11,2

5,9

75,5

90,5

80,3

58,0

39,2

2,3

A

Ce

713

0,0

CC E

La

N U SC R

34,6

A

141

Ba

578

M

116

ED

Sr

Pr

0,10

0,14

0,11

0,54

10,5

1,9

1,0

1,2

1,4

1,3

9,1

10,5

10,0

7,1

4,5

0,75

Nd

0,16

0,37

0,32

2,0

40,1

7,3

4,6

5,1

5,3

5,2

34,5

40,3

38,8

26,6

17,5

3,4

Sm

0,07

0,10

0,10

0,46

6,9

1,4

1,4

1,0

1,1

1,1

7,4

7,0

6,4

4,7

3,3

0,64

Eu

0,016

0,027

0,023

0,10

1,1

0,39

0,37

0,26

0,21

0,37

1,55

1,52

0,85

1,0

0,57

0,17

Gd

0,10

0,14

0,12

0,45

5,2

1,4

1,7

1,4

0,89

1,6

7,0

7,1

5,8

3,9

2,5

0,82

Tb

0,014

0,076

0,019

0,079

0,68

0,22

0,29

0,21

0,15

0,24

1,02

1,10

0,80

0,52

0,31

0,12

I 0,50

3,2

1,3

Ho

0,024

0,035

0,033

0,11

0,61

0,26

Er

0,088

0,119

0,11

0,35

2,0

0,78

Tm

0,012

0,018

0,017

0,052

0,31

0,10

Yb

0,077

0,11

0,10

0,32

2,3

0,64

Lu

0,012

0,02

0,017

0,049

0,35

0,090

Hf

0,00

0,00

0,00

0,28

3,1

Ta

0,00

0,00

0,0054

0,10

0,97

W

0,0

0,0

0,049

0,23

Re

0,0

0,0

0,0

Ir

0,00

0,00

0,00

Pt

0,00

0,00

Au

0,00

0,00

0,82

1,3

5,7

6,66

4,62

2,4

1,5

0,76

0,40

0,29

0,16

0,28

1,12

1,28

0,95

0,46

0,26

0,17

1,2

0,8

0,47

0,79

3,3

3,7

2,7

1,4

0,8

0,52

0,16

0,11

0,065

0,10

0,50

0,53

0,44

0,22

0,13

0,065

0,93

0,64

0,41

0,65

3,0

3,4

3,0

1,6

1,0

0,44

0,13

0,10

0,063

0,09

0,47

0,53

0,44

0,25

0,15

0,059

0,27

0,47

0,34

0,42

0,16

5,6

6,0

6,1

2,1

1,8

< bdl

0,072

0,059

0,045

0,046

0,001

1,12

1,26

1,15

0,83

0,61

< bdl

1,2

0,18

0,24

0,12

0,11

0,26

1,8

1,0

0,066

0,0

0,0

0,0

0,0

0,0

0,0

0,0

< bdl

< bdl

< bdl

0,00

0,00

0,00

0,00

0,00

0,00

0,00

< bdl

< bdl

< bdl

PT

0,0010

0,0010

0,0010

0,00

0,00

0,0010

0,00

< bdl

< bdl

< bdl

0,00

0,00

0,00

0,00

0,00

0,00

0,00

0,00

< bdl

< bdl

< bdl

-

-

-

-

-

-

-

-

-

-

-

-

-

0,0

0,0

0,001

0,20

1,2

0,16

0,092

0,013

0,055

0,017

1,1

0,95

0,016

0,23

0,99

0,41

4,0

1,7

5,8

3,6

2,0

1,8

1,9

7,2

10,8

2,5

0,057

0,083

< bdl

3,2

4,5

2,1

A

Pb

1,3

0,0010

CC E

Tl

N U SC R

0,11

A

0,136

Hg

1,8

M

0,090

ED

Dy

Bi

0,00

0,00

0,001

0,049

0,071

0,031

0,038

0,001

0,012

0,023

Th

0,00

0,00

0,035

1,5

12,2

1,1

1,4

0,51

1,4

0,50

11,1

13,3

12,4

7,8

6,8

0,14

U

0,080

0,18

0,79

0,14

2,0

1,7

0,61

0,66

5,0

0,60

2,1

2,9

4,2

1,3

1,2

0,61

LREE/HR EE

4,12

4,18

3,69

8,08

20,18

11,43

4,31

6,11

12,09

6,36

11,35

11,74

14,63

19,01

20,94

5,906

Sr/Ba

17,07

35,95

4,11

0,50

0,41

16,04

14,82

14,35

5,25

24,04

0,072

0,015

0,04

0,12

0,11

10,36

U/Zr

79,60

0,14

1,54

0,019

0,026

0,19

0,04

0,090

0,40

0,16

0,009

0,013

0,018

0,016

0,019

I 3395,3

Mn/Sr

0,00006

0,0001

6,23

0,709

0,462

2,765

0,00024

0,0002

N U SC R

3129

4,787

3,03

0,00046

0,00023

A

CC E

PT

ED

M

A

Co/Th

0,98

7,67

1,04

0,00037

0,00019

1,58

0,54 0,00018

1,42

1,39

Table 5. Sample

Isotopic composition of Carboniferous limestones Unit, Age

Location

Lithology

δ13C

δ18О

0

22,3

0,2

18,2

1a. Central Tectonic Zone of Wrangel Island Light gray limestone Krasnyi Flag River

Unit D3-C1, 700/6

Gray limestone

C1tour

Krasnyi Flag River

Unit D3-C1,

Gray limestone

C1tour

Krasnyi Flag River

705/1

Unit C1, C1 ser?

Krasnyi Flag River

Gray limestone

2,2

705/3

Unit C1, C1 ser?

Krasnyi Flag River

White limestone

2,4

26,1

498/3-1

Unit C1, vis-ser

Khrustalnyi Creek

Gray limestone

4,4

23,7

Light gray silty limestone

4,3

23,7

Lenticular light gray silty limestone

3,4

22,9

Silty limestone

4,4

23,7

2,5

23,43

Gray and black limestone

5,5

19,4

Cement of conglomerates, light gray limestone

4,9

20,4

4,1

23,3

4,0

22,6

4,5

24,1

5,6

20,6

SC R

703/4

Khrustalnyi Creek

U

Unit C1, vis-ser

1,3

IP T

700/5

Unit D3-C1, C1tour

Khrustalnyi Creek

498/4-3 Unit C1, vis-ser

Khrustalnyi Creek

M

498/5

A

Unit C1, vis-ser

N

498/4-2

ED

Average

Krasnyi Flag River

Unit C2, C2 mos

496/4-4

Unit C2, bashmos

496/4-3

Unit C2, bashmos

Neizvestnaya River

496/4-2

Unit C2, bashmos

Neizvestnaya River

496/4-1

Unit C2, bashmos

Neizvestnaya River

496/2

Unit C2, bashmos

Neizvestnaya River

A

CC E

PT

706/2

Neizvestnaya River

23,9 26,4

Light gray limestone

Light gray limestone with cherts Gray limestone

Gray limestone

77

496/1

Unit C2, bashmos

Neizvestnaya River

651/2

Unit C2, C2

Neizvestnaya River

655/2

Unit C2, C2

656/1

Unit C2, C2

White silty limestone

21

Light gray limestone

5,4

21,6

Neizvestnaya River

White and gray limestone

5

20,6

Neizvestnaya River

Dark gray limestone

5,6

25,2

4,97

21,88

Average

1b. Southern Tectonic Zone of Wrangel Island

490/5

Unit D3-C1, C1tour-vis

Khishchnikov River

490/5-2

Unit D3-C1, C1tour-vis

Khishchnikov River

490/8

Unit D3-C1, C1tour

Khishchnikov River

500/2-1

Unit D3-C1, C1tour-vis

Somnitelnaya River

501/2-1

Unit D3-C1, C1tour-vis

Somnitelnaya River

501/2

Unit D3-C1, C1tour-vis

715/1

Unit D3-C1, tour

Silty limestone

SC R

0,4

IP T

5,1

19,5

Limestone

0,8

19,2

3,1

23,3

2,6

16,6

1,6

19,6

0,7

14,1

U

White limestone

A

N

Dark gray limestone

M

Gray silty limestone

Light gray limestone

ED

Somnitelnaya River

Dolomitic limestone

3,4

24,5

721/1

Unit D3-C1, tourvis

Uering Cape

Calcareous cherty mudstone

5

23,5

721/2

Unit D3-C1, tourvis

Uering Cape

Gray dolomitic limestone

4,7

24,8

722/1

Unit D3-C1, tourvis

Uering Cape

5

23,6

722/2

Unit D3-C1, tourvis

Uering Cape

5,1

24,6

722/5

Unit D3-C1, tourvis

Uering Cape

4,3

21

605/3

Unit D3-C1, C1vis

Khishchnikov River

-2,6

19,2

A

CC E

PT

Uering Cape

Gray limestone

Lens of limestone

Dolostone

Gray and white limestone

78

Unit D3-C1, C1vis

Khishchnikov River

Mudstone

-8,7

18

612/4

Unit D3-C1, C1vis

Khishchnikov River

Limestone with cherts

4,8

21,6

487/1a

Unit D3-C1, C1vis

Khishchnikov River

Gray limestone

-6,6

18,1

Khishchnikov River

Gray and brown limestone

-4,7

16,7

-6,6

17

487/1b

Unit C1, C1vis

Unit C1, C1vis

Khishchnikov River

Gray and brown limestone

487/3

Unit C1, C1vis

Khishchnikov River

Gray limestone

-8,6

487/4

Unit C1, C1vis

Khishchnikov River

Gray mudstone

0,2

SC R

487/2

IP T

606/1

19,7

0,177

20,11

Unit C2, C2bash

Somnitelnaya River

Gray limestone, calcarenite

1,1

12,2

732/1

Unit C2, C2mos

V’uchny Creek

Gray silty limestone

0,2

17,2

735/1

Unit C2, C2mos

V’uchny Creek

Dark gray limestone

2,4

17,9

492/20

Unit C2,

Cape Ptichii Bazar

Gray silty limestone

-4,5

14,8

492/23-1

Unit C2,

Cape Ptichii Bazar

Gray limestone

-3,2

19

492/24-1

Unit C2,

Cape Ptichii Bazar

Limestone with Fauna

5,4

20,4

489/7

Unit C2, bash

Khishchnikov River

Brown limestone

1,4

19,4

0,4

17,27

A

M

ED

PT

CC E

Average+/-

N

601/11-1

U

Average+/-

17,5

2. Kibera Cape, Kuul Uplift

C1 serp

Kibera Cape

Limestone

4.3

17,9

M10/13

C2 mos

Kibera Cape

Calcareous sandstone

0.9

18,3

M10/17-2

C2 mos

Kibera Cape

Dolomite limestone

1.3

28

2,17

21,4

A

M10/11-1

Average

3. Alyarmaut Uplift 406/1

С1vis

Lyupveem R.

Gray limestone

2,9

21,6

406/4-1

С1vis

Lyupveem R.

Gray and white

0,6

5,7??

79

limestone

406/4-2

С1vis

406/5а

С1vis

Lyupveem R.

Lyupveem R.

Gray and white limestone

3,7

21,1

Gray and white lenticular limestone

1,5

13,4

Gray and black limestone

-1,9

24,4

-2,0

24,1

406/6

С1vis

406/7

С1vis

Lyupveem R.

Black limestone

С1vis

Prokhladnyi Creek., Pogynden R.

Gray limestone

458/2

С1vis

Prokhladnyi Creek., Pogynden R.

Gray and white limestone Gray limestone

458/4

С1vis

Prokhladnyi Creek, Pogynden R.

С1vis

Prokhladny Creek, Pogynden R.

Gray limestone

458/5

458/6

С1vis

Prokhladny Creek, Pogynden R.

458/7

С1vis

С1vis

459/8

CC E

Average+/-

С1tour-vis?

202/2

SC R -3,7

17

3,7

28,2

Gray and white limestone

3,7

20,5

Prokhladny Creek, Pogynden R.

White and gray limestone

4,1

21,5

Prokhladny Creek, Pogynden R.

White and gray limestone

2,7

24,4

Prokhladny Creek, Pogynden R.

Marl slate

5,5

19,3

0,69

18,6

M

A

N

U

15,9

ED

458/8

4. Polyarnyui Uplift

C1vis

Polyarnyui Creek

Gray limestone

2,2

23,9

C1vis

Polyarnyui Creek

Gray and red limestone

2,2

23,5

Red and gray limestone

3,5

22,3

2,63

23,23

202/3

A

16,7

-4,4

PT

458/3

-4

IP T

Lyupveem R.

C1vis

Polyarnyui Creek

003/2 Average

80

A

CC E

PT

ED

M

A

N

U

SC R

IP T

tour – Tournaisian, vis – Visean, ser – Serpukhovian, bash – Bashkirian, mos – Moscovian, kas Kasimovian

81