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This paper presents a description of the Olenekian–Anisian sections in South Primorye, Far East Russia, containing reptile remains. The paper describes important ammonoid Flexoptychites cf. rifunus (Yabe et Shimizu), as well as Flexoptychites cf. compressus (Yabe et Shimizu), which are stratigraphically significant. New Anisian reptile remains were discovered from four stratigraphic levels in South Primorye: (1) the upper part of the middle Anisian Acrochordiceraskiparisovae Zone (Ichthyopterigia indet. A), (2) the middle part of the upper Anisian Flexoptychites cf. rifunus Beds (Reptilia indet. cf. Ichthyopterygia A), (3) the upper part of the upper Anisian Flexoptychites cf. rifunus Beds (Ichthyoterygia indet. B), and (4) the uppermost part of the upper Anisian Flexoptychites cf. rifunus Beds (Reptilia indet. cf. Ichthyopterygia B). The Anisian stage is marked by an abundance of medium- to large-sized ichthyopterygians and a comparatively limited number of gigantic forms, particularly in the eastern Panthalassic and western Tethyan provinces. Our recent discovery has unveiled the presence of medium- to large-sized reptiles, seemingly ichthyopterygians, in the western Panthalassic province during the late Anisian (Flexoptychites cf. rifunus Chrone). [ABSTRACT FROM AUTHOR]

A new elasmobranch assemblage including 14 shark taxa, mainly lamniformes (9 taxa), is described from the Lower Eocene (NP 10–11) Kalinino Formation of the Alai River Basin, Baltai District, Saratov Region of Russia. The Nikulinka elasmobranch assemblage may have characterised inner neritic environments of the eastern part of the sub-boreal European paleobiogeographic region, being closely related to assemblages from the south-most sector of the boreal Western Siberian Province (southern Trans-Urals and Turgay straight). The absence of myliobatids in Nikulinka and Trans-Uralian localities may have been caused by the influence of Arctic water masses through meridional straits in early Ypresian. This is the first chondrichthyan assemblage from the Palaeogene of the Middle Volga Region, European Russia. [ABSTRACT FROM AUTHOR]

Brachiopods from the upper part of the Khalpirkian Regional Stage of the Tiryakh–Kobyume section of the Kobyume structural–facies zone in Southern Verkhoyanie have been studied. The collection is dominated by Strophalosia? vollossovitschi (Fredericks) and Cancrinella? sp. Single spiriferids are assigned to Crassispirifer monumentalis Abramov et Grigorjeva and Cr. aff. monumentalis Abramov et Grigorjeva, and, thus, host deposits are referred to the Crassispirifer monumentalis Beds. We found these beds earlier only in the lower part of the Khalpirkian Regional Stage. Reliable findings of the terminal brachiopod assemblage confined to the Khalpirkian of the Upper Permian have been reviewed. The assemblage is dominated by strophalosiids represented by Wyndhamia gijigensis (Zavodowsky), Marginalosia? magna Abramov et Grigorjeva, Subtaeniothaerus lungersgauzeni Solomina, and Strophalosia? aff. vollossovitschi (Fredericks). "Magadania" sp. and Cancrinella? sp. have been identified from linoproductids. Crassispirifer monumentalis spiriferids are an important element of the terminal assemblage. Athyridids of the Khalpirkian Regional Stage, known only in its lower part, are represented by Cleiothyridina nikolaevi Grunt, Cleiothyridina sp., and Bajtugania sp. The studied regional stage also contains findings of terebratulids attributed to Marinurnula? aff. mantuanensis (Campbell) and M.? aff. chivatschense (Zavodowsky). No brachiopods are known at the top of the Khalpirkian Regional Stage, while rhynchonellids Piarorhynchia sp. appear at the base of the Nekuchan Regional Stage. At the beginning of the Khalpirkian, the brachiopod community had an extended natural habitat in the shelf zone of the Verkhoyan Sea along the Angaraland coastline. Subsequently, this area was reduced and initially divided into two independent subareas confined to the East Kharaulakh and South Verkhoyan sectors. In the Late Khalpirkian, the brachiopod community was concentrated only in the Kobyume zone, where it ended up under the end-Permian mass extinction. Some taxa of the identified brachiopod assemblage have been traced in the Okhotsk region, the Ayan—Yuryakh anticlinorium, and the Omolon massif. [ABSTRACT FROM AUTHOR]

A continuous outcrop of the neritic sediments ranging from the Cretaceous/Paleogene to Eocene/Oligocene boundary is exposed along the Kheu R., Kabardino-Balkaria Republic, southern Russia. High calcareous nannofossil abundance and species diversity in Kheu section make possible the application of various standard calcareous nannofossil zonations for the investigated interval. This provides a direct correlation of the biohorizons used as zonal markers in these zonations and recognition of the stage boundaries in this complete succession, which represents the reference Paleogene section of the NE Peri-Tethys. The carbon and oxygen isotope records revealed a series of excursions correlated to peculiar Paleogene paleoecological events on the basis of nannofossil biostratigraphy. The continuous Maastrichtian/Danian transition displays ca. 1 m thick interval containing only scarce Cretaceous survivors between the highest occurrence (HO) of the most Cretaceous nannofossil taxa and the lowest occurrence (LO) of the Paleogene taxa; this interval is characterized by prominent positive δ13C and δ18O excursions. The Late Danian Event (LDE) is identified as minor δ13C and δ18O excursions in the upper Danian. The base of Selandian stage is defined by the 2nd radiation of fasciculiths, followed by negative δ13C and δ18O shifts corresponding to the Danian/Selandian Transition Event. Mid-Paleocene Biotic Event (MPBE), A, B1/B2, C1/C2 and D1/D2 events are pronounced in the upper Paleocene C and O isotope record. Wide expansion of Discoasterales (Fasciculithus, Heliotrochus, Heliolithus, Discoaster), served as a basis for nannofossil zonations, is featured for this time span. The base of Ypresian (lower Eocene) corresponds to the onset of the carbon isotope excursion (CIE) documented at the base of the TOC-rich bed. This 0.6 m thick sapropelitic bed corresponds to the Paleocene–Eocene Thermal Maximum (PETM) and contains specific nannofossil assemblage known as "excursion taxa". The high sedimentation rate and completeness of the early Eocene sedimentary succession allowed to record the evolution of Tribrachiatus bramlettei–T. digitalis–T. contortus–T. orthostylus lineage spanning the interval of NP10–NP12 zones. Multiple δ13C and δ18O excursions, occurred in the lower Ypresian sediments, correspond to the early Eocene hyperthermals E1/E2, F1, F2, G, ETM2, I1/I2 and J. The intercalations of a series of TOC-rich layers in the interval ranging the upper NP12 to lower NP13 zones correspond to ETM3 and individual episodes (L-T) of the Early Eocene Climatic optimum (EECO). Long-term cooling trend in the Caucasian basin begins in the uppermost Ypresian (upper NP13 zone). The middle Eocene δ18O record demonstrates a succession of negative excursions occurred against the background of relatively high values. The hyperthermal C21r–H6 is recognized at the base of Lutetian stage defined by the LO of Blackites inflatus. Two later excursions of this time interval corresponding to the Late Lutetian Event (LLE) and Middle Eocene Climatic Optimum (MECO) occur in the enriched in TOC Kuma Fm. (late Lutetian to Bartonian) and fall at the levels with highest TOC concentrations. Nannoplankton assemblages are widely dominated by eurytopic reticulofenestrids during both events, while Chiasmolithus and Discoaster become oppressed that can indicate lower salinity caused by enhanced humidity. The base of Priabonian is defined by the LO of Chiasmolithus oamaruensis and the base of Cribrocentrum erbae acme. These bioevents are preceded by the negative δ13C excursion and very positive δ18O values, possibly correlated to the Priabonian Oxygen Maximum (PrOM). The relatively warm Priabonian time, characterized by recovery of Chiasmolithus, Discoaster and Sphenolithus, gives way to a new cooling phase known as Late Eocene Event (LEE). The base of Clausicoccus subdistichus acme, approximated to the base of Oligocene, falls at the level ca. 0.5 m below the facial change corresponding to the large-scale sea-level fall and, thus, slightly precedes the accumulation of low-calcareous oil-bearing Oligocene-lower Miocene Maikop Fm. The prominent positive δ13C and δ18O excursions occur at the base of this formation. [ABSTRACT FROM AUTHOR]

The paper studies sediments from Lake Tikozero that have accumulated successively in the littoral of Lake pre‐Imandra, Imandra lagoon, and an open lake isolated from a parental freshwater body. The 'Apatity' bog was concurrently formed on the Lake Imandra coast. Lithological, 14C, pollen and diatom data and findings of previous investigations provide the regional Holocene stratigraphy, which is subdivided into the early (c. 11 550–8200 cal a bp), middle (c. 8200–4000 cal a bp) and late (last 4000 cal a bp) Holocene sub‐stages. In the early Holocene, environments became favourable for diatoms after c. 9700 cal a bp. Birch phytocoenoses and pine forests with birch flourished in the area. In the middle Holocene, the west‐central Kola Peninsula was covered by a pine‐birch forest with alders. Lake Tikozero became shallow and desiccated in a warm and dry climate between c. 6300 and 4000 cal a bp; and a Sphagnum raised bog developed in the adjacent area, provoked by lowering of the water table. Spruce appeared in a pine‐birch forest and indicates a colder and wetter climate in the late Holocene. The flooding of Lake Imandra created a number of new small lakes; and fens occurred along the wet shores. [ABSTRACT FROM AUTHOR]

The results of study of marine and terrestrial palynomorphs in the Lower Kimmeridgian and Middle-Upper Volgian in the Eganovo section (Moscow region) are presented. The section is well characterized by ammonites providing a biostratigraphic control of the palynostratons. Beds with spores and pollen are identified for the Volgian interval and beds with dinocysts are distinguished for the entire section. Certain taxa allow comparison of synchronous successions of dinocysts of the European part of Russia, Siberia, and Western Europe. By spores and pollen, a correlation is possible with coeval rocks of the northern Urals, Western Europe, and Australia. The facies analysis of two palynological groups allowed reconstruction of features of marine algoflora and their interrelation with transgressive–regressive dynamics of the paleobasin, climatic fluctuations, and change in coastal landscapes. The comparative analysis of the lateral distribution of coeval dinocyst assemblages from the Eganovo section and other Boreal regions showed a significant similarity of algoflora of European Russia, the North Sea region, and Bulgaria in the Kimmeridgian, but the lateral differentiation of algoflora increased to the end of the Volgian. At the same time, the diversity of the dinocyst assemblages in the European part of Russia remained high. It is suggested that this was caused by favorable temperature and trophic conditions, which are interpreted using the results of facies analysis of terrestrial palynomorphs. The features of their taxonomic composition are typical of the Euro-Sinian paleogeographic area with a subtropical climate. Gradual cooling in the second half of the Volgian was accompanied by recovery of small climatic maxima, which are also traced in Western Europe, Siberia and the northern Urals. No period of aridization typical of the terminal Jurassic of Western Europe was revealed. Wet conditions led to the formation of specific palynoflora with abundant gleicheniaceous ferns in the European part of Russia and adjacent territories of the Urals and margins of Western Siberia. [ABSTRACT FROM AUTHOR]

The complete sections of the Lower and Upper Vendian of the East European Platform were opened in the boreholes of Belarus. This allows us to consider this region as a stratotype area. In order to update the paleontological characteristics of the Vendian, organic-walled microfossils from the Bogushevsk-1, Bogushevsk-2 (Liozno), and Lepel-1 reference boreholes drilled in the north of the Orsha Depression were studied. The transitive assemblage I with Leiosphaeridia minutissima–Leiosphaeridia tenuissima was recognized in the Lower Vendian Liozno Formation of the Volyn Series and the Upper Vendian Kotlin Formation. The Redkino microfossil assemblages were identified at three stratigraphic levels in the Nizy, Selyava, and Chernitsa formations: assemblage II with Morania zinkovi, assemblage III with Morania zinkovi–Tynnia precambrica, and assemblage IV with Morania zinkovi–Tynnia precambrica–Striatella coriacea, respectively. The Kotlin assemblage V with Vendotaenia antiqua–Primoflagella speciosa was distinguished in the upper part of the Kotlin Formation (Bogushevsk-1 borehole). On the basis of the taxonomic composition, assemblages III and IV are correlated with the first Redkino biota of the Starorusskaya Formation; assemblage V is correlated with the third Kotlin biota of the Vasileostrovskaya Formation of the northwestern part of Russia. Our data show a high biostratigraphic potential of organic-walled microfossils, which should be used to substantiate regional stratigraphic units of the Upper Vendian in the updated stratigraphic scheme of the East European Platform. [ABSTRACT FROM AUTHOR]

Information on latest early Olenekian (latest Smithian) ammonoids is available apparently from only seven regions of the world, including South Primorye. Latest Smithian evidences on this topic are recorded from the West SMID (abbreviation from the Russian name of the quarry: "Building Materials and Details"), East SMID and Golyj Cape areas in South Primorye. This provides additional information on systematic composition of latest Smithian ammonoid, as well as conodont and brachiopod assemblages from the recently identified Shimanskyites shimanskyi Zone, located between lower Olenekian Anasibirites nevolini Zone and upper Olenekian Tirolites subcassianus Zone. There are many common ammonoid species in the Shimanskyites shimanskyi Zone and the underlying Anasibirites nevolini Zone, e.g., Prosphingitoides sp., Arctoceras septentrionale (Diener), Churkites syskoi Zakharov et Shigeta, Submeekoceras? subhhydaspis (Kiparisova), Prionites markevichi Zakharov et Smyshlyaeva, 'Anasibirites' simanenkoi Zakharov et Smyshlyaeva, Xenoceltites? subvariocostatus Zakharov et Smyshlyaeva, and Mianwaliites zimini Zakharov et Smyshlyaeva. The base of the Shimanskyites shimanskyi Zone, marked by a negative δ13Corg excursion in the Kamenushka-2 Section by our previous study, coincides with the FO (first occurrence) of ammonoids Shimanskyites shimanskyi Zakharov et Smyshlyaeva and Glyptophiceras cf. sinuatum (Waagen) and conodont Hindeodella budurovi Buryi. This zone is characterized additionally by some fossils common for the overlying upper Olenekian Tirolites subcassianus Zone: ammonoids of the genus Kamenushkaites, brachiopods Bittnerihyris margaritovi (Bittner) and Lepismatina sp. and conodont 'Neogondolella' (=?Borinella) jubata Sweet. The latest Smithian ammonoids recorded from the Shimanskyites shimanskyi Zone totally consist of 30 taxa belonging to 11 families (Sageceratidae, Ussuiriidae, Aspenitidae, Paranannitidae, Arctoceratidae, Proptychitidae, ?Galfetitidae, Prionitidae, ?Kashmiritidae, Xenoceltitidae and Palaeophyllitidae). The problems of global correlation of uppermost Smithian strata are also discussed. [ABSTRACT FROM AUTHOR]

Erythrosuchid archosauriforms are quadrupedal carnivorous reptiles with a proportionally huge skull. They represent one of the first evolutionary radiations of medium to large predatory diapsids after the Permo–Triassic mass extinction. Erythrosuchids are known from Lower– Middle Triassic rocks of South Africa, Russia, and China, and there have been preliminary reports from the Middle Triassic Yerrapalli Formation of south-central India. Here we describe, compare and figure for the first time these Indian erythrosuchid remains. We erect the new genus and species Bharitalasuchus tapani based on a holotype and paratype that preserve tooth-bearing cranial fragments, at least 17 presacral vertebrae, some ribs and probable intercentra, and partial shoulder and pelvic girdles and hindlimb and allow recognizing a series of autapomorphies and unique combination of character states among erythrosuchids. Our phylogenetic analysis recovered Bharitalasuchus tapani most closely related to Shansisuchus shansisuchus and Chalishevia cothurnata from the late Anisian of China and Ladinian of Russia, respectively. The phylogenetic affinities of this new taxon and a revision of the tetrapod assemblage of the Yerrapalli Formation shed light on the age of this unit. The presence of the Wadiasaurus-Rechnisaurus-Bharitalasuchus association in the Yerrapalli Formation closely resembles the Sinokannemeyeria- Shansisuchus dicynodont-erythrosuchid association of late Anisian to early Ladinian Chinese units. This evidence supports a post-early–middle Anisian age, even possibly early Ladinian, for the Yerrapalli Formation. The presence of possibly one of the last erythrosuchids in India would indicate that the clade still retained both a northern and southern Pangean distribution before its extinction. [ABSTRACT FROM AUTHOR]

An abundant collection of bivalves, belonging to the stratigraphically important genus Retroceramus, has been described for the first time from the Bajocian‒Bathonian beds of the Timan-Pechora region, exposing along the Izhma River and its right tributary, the Dreshchanka River. Totally 7 taxa were found, among which 4 were identified to a species level (and 2 of them are new taxa), and other 3—in the open nomenclature. The earliest retroceramid assemblage occurs below the occurences of the Late Bajocian zonal ammonite index, Arctocephalites arcticus, in the strata lacking ammonites. The assemblage allowed to correlate this part of the section to the Lower (?) Bajocian. Such an assumption is based on the identifications of two retroceramid species, previously reported from the Lower Bajocian of the Asian part of Russia only—R. (R.) elongatus Kosh., 1960 and R. (R.) cf. lungershauseni Kosh., 1962. In its upper part, the ammonite-free interval contains a new species R. (R.) alliensis Zakharov, sp. nov., as well as a new peculiar unionid Mezounio zverkovi Zakharov, gen. et sp. nov., sometimes met as accumulations. The overlying Upper Bajocian Arctocephalites arcticus ammonite Zone yielded a few specimens of R. (R.) startensis Polub., 1992, R. (R.) elongatus Kosh., 1960 and R. (?) inopinatus Zakharov, sp. nov. The above part of the succession which is not characterized by ammonites and probably corresponds to the Bajocian/Bathonian boundary interval contains R. (R.) cf. eximius (von Eichw.). Additionally, a single specimen of R. (R.) sp. indet. was found in the Lower Bathonian Arcticoceras ishmae Zone. [ABSTRACT FROM AUTHOR]

The Kosika locality is situated on the lowest terrace of the Enotayevka River (right channel of the Volga River) near Kosika village, in the Astrakhan region of the Russian Federation. This locality includes several sections, named Kosika 1–4 and Borehole 2 Kosika that are described in detail for the first time. Drilling, sediment descriptions, and sampling were performed during the 2008–2015 field seasons. Application of complex biostratigraphical methods and optically stimulated luminescence (OSL) dates were used to reconstruct the Neopleistocene (Middle-Late Pleistocene) palaeoenvironment in the Lower Volga area. During the Tyurkyan Period (at the early beginning of the Neopleistocene), regression of the Apsheronian Sea began. Lithological features and the presence of freshwater molluscs demonstrate that deposits accumulated in rivers and lakes under humid climatic conditions. Molluscs, ostracods, and dinoflagellates inhabited the Baku Sea. Climate was arid at the beginning of this period and humid during a later phase. Several changes affecting the marine and fluvial environments characterise the Early Khazar period. In particular, the climate oscillated from humid conditions at the beginning to an arid state, then returned to a more humid setting at the end of this period. These changes are indicated by palynological and malacological data. Regression of the Early Khazar Sea occurred during Singil time, when rivers, lakes, and limans (lagoons) existed. Large mammals inhabited plains that were covered by extensive vegetation. The climate during this period was humid and slightly cooler than the present day climate. Late Khazar and Khvalyn transgressions occurred during the Late Neopleistocene. When the Late Khazar Sea retreated from the territory, river valleys became the dominant landscape feature. Floodplains of Late Khazar rivers became sites of deposition of loamy and sandy material emplaced during flood events. At the end of this regressive period, the climate was arid and dry enough to allow for accumulation of anhydrite sediment in shallow lagoons and lakes. Afterwards, the Khvalyn transgression began, as indicated by the occurrence of specific key mollusc species. Fluvial-marine deposits formed geological bodies representative of an undersea delta, which in relief form the Baer Knolls. The modern Volga valley was formed during the Holocene. [ABSTRACT FROM AUTHOR]

The Ordovician Period has emerged as a highly dynamic time in Earth history. Comprehensive work on chrono, chemoand biostratigraphy has resulted in an overall wellconstrained systemic framework, but several local successions around the globe still await detailed analysis in many respects. Herein we perform a highresolution analysis of abiotic and biotic signals in the Lynna River section, a key locality in northwestern Russia. As this section has been pivotal in documenting the temporal evolution of the Great Ordovician Biodiversification Event on Baltica, the macroscopic and microscopic characteristics of the local succession reveal important paleoenvironmental information that ties into the global development during the Middle Ordovician. The results add particularly to the understanding of the characteristics and largescale sedimentary 'behavior' of the Baltoscandian paleobasin. Microfacies vary consistently with the macroscopic appearance of the rocks, with intervals characterized by competent limestone being associated with coarser carbonate textures and intervals dominated by marly beds associated with finer textures. Along with carbonate textures, fossil grain assemblages vary in a rhythmic (~cyclic) manner. The local rocks are commonly partly dolomitized, with the proportion of dolomitization increasing upsection. Regional comparisons suggest that the changes in overall macroand microfacies were strongly related to variations in sea level. New highresolution conodont biostratigraphic data largely confirm previous regional correlations based on lithostratigraphy and trilobite faunas, and enable more robust correlations worldwide. [ABSTRACT FROM AUTHOR]

The lower Eocene sediments from the classical Paleogene section exposed along the Kheu River, northern Caucasus, southern Russia are here studied. This ca. 50m thick succession is lithologically contrasting: the lower and upper parts are composed by soft marls separated by a thick Radiolaria-rich unit of non-calcareous and low-calcareous mudstones with intercalations of compact cherty layers. According to nannofossil and dinocyst biostratigraphy, the unique intercalation of Total Organic Carbon (TOC)-rich sediment (sapropelitic bed) in the lower part of the lower Eocene correspond to the Paleocene-Eocene Thermal Maximum (PETM) and a series of sapropelitic interlayers in the upper marly part of the lower Eocene succession correlates with the Early Eocene Climatic Optimum (EECO). The study of nannofossil and dinocyst assemblages enabled detailed zonal subdivision and first-order calibration of nannofossil and dinocyst bio-events during this time-span. The studied interval of the section embraces the complete succession of nannofossil zones NP9-NP13 of Martini, 1971, CP8-CP11 of Okada and Bukry, 1980 and CNP11-CNE5 of Agnini et al., 2014. By means of dinocyst stratigraphy, the succession of Apectodinium hyperacanthum, Axiodinium augustum, Deflandrea oebisfeldensis, Dracodinium astra, Stenodinium meckelfeldense, Dracodinium varielongitudum, Ochetodinium romanum/Samlandia chlamydophora and Areosphaeridium diktyoplokum zones are identified in the Ypresian part of the Kheu section. [ABSTRACT FROM AUTHOR]

Based on the stratigraphic distribution of benthic foraminifera in the lower bathyal-abyssal sediments uncovered by boreholes drilled under the framework of the Deep Sea Drilling Project (DSDP) and Ocean Drilling Project (ODP) in the Northern and Southern Pacific, the Lower Paleogene biostratigraphic zonal scale based on deep-water benthic foraminifera is proposed. The proposed scale includes eight subdivisions: six zones and two subzones. The boundaries of the zonal subdivisions are determined by biotic events (appearance or disappearance (extinction)) of stratigraphically important taxa and are correlated to the zonal scales based on planktonic foraminifera and calcareous nanoplankton. Most of these events are considered to be subglobal. [ABSTRACT FROM AUTHOR]

The “calcaires à Productus ” of the Montagne Noire (Aude-Hérault, southern France) are carbonate lenses embedded within a thick Carboniferous siliciclastic complex. Foraminiferal assemblages in some of the larger carbonate lenses are typically representative of the late Viséan and Serpukhovian. Eleven new species of foraminifers are described: Hemidiscopsis variabilis , H. pilleae , Planohowchinia rara , P. redondensis , Spireitlina minima , Rectoendothyra japhetensis , Mikhailovella enormis , Cribrospira ? perretae , Pojarkovella occidentalis , Parabiseriella vailhanensis , and Biseriella delicata . Eight foraminiferal biozones are defined; they are based on the first occurrence of some taxa, and could be used for other regions of southern France (e.g., Mouthoumet and the Pyrenees). These biozones are informally named as A to H. Due to the problems with classical biozonations and substages in northern England as well as Belgium and northern France, the biozones established herein are mostly compared with the Russian standard substages. Thus, biozones A and B are correlated with the Mikhailovian, corresponding to the latest Asbian and earliest Brigantian in western Europe; biozones C, D and E are correlated with the Venevian, equivalent to the upper part of the early Brigantian in western Europe. Therefore, biozones A–E form part of the late and latest Viséan. The stratigraphically younger biozones F, G and H contain foraminiferal assemblages correlated with the Tarusian, Steshevian and Protvian, respectively. [ABSTRACT FROM AUTHOR]

The upper Viséan-Serpukhovian strata in the type region for the Serpukhovian Stage is an epeiric-sea succession ca. 90 m in thickness. The predominantly Viséan Oka Group (comprising the Aleksin, Mikhailov, and Venev formations) is dominated by photozoan packstones with fluvial siliciclastic wedges developed from the west. The Lower Serpukhovian Zaborie Group is composed of the Tarusa and Gurovo formations. The latter is a new name for the shale-dominated unit of Steshevian Substage age in the studied area. The Zaborie Group is composed of limestones and marls in its lower (Tarusa and basal Gurovo) part and black smectitic to grey palygorskitic shales in the main part of the Gurovo Formation. The Gurovo Formation is capped by a thin limestone with oncoids and a palygorskitic-calcretic palaeosol. The Upper Serpukhovian is composed of a thin (3-12 m) Protva Limestone heavily karstified during a mid-Carboniferous lowstand. The succession shows a number of unusual sedimentary features, such as a lack of high-energy facies, shallow-subtidal marine sediments penetrated by Stigmaria, the inferred atidal to microtidal regime, and palustrine beds composed of saponitic marls. The succession contains many subaerial disconformities characterized by profiles ranging from undercoal solution horizons to palaeokarsts. Incised fluvial channels are reported at two stratigraphic levels to the west of the study area. The deepest incisions developed from the Kholm Disconformity (top of the Mikhailov Formation). This disconformity also exhibits the deepest palaeokarst profile and represents the major hiatus in the Oka-Zaborie succession. The new sea-level curve presented herein shows two major cycles separated by the Kholm Unconformity at the Mikhailov/Venev boundary. The Lower Serpukhovian transgression moved the base-level away from falling below the seafloor so that the section becomes conformable above the Forino Disconformity (lower Tarusa). The maximum deepening is interpreted to occur in the lower dark-shale part of the Gurovo Formation. The base of the Serpukhovian Stage is defined by FADs of the conodont Lochriea ziegleri and the foraminifer Janischewskina delicata in the middle of the sequence VN2. The Aleksinian-Mikhailovian interval is provisionally correlated with the Asbian (Lower-Middle Warnantian) in Western Europe. Based on FODs of Janischewskina typica and first representatives of Climacammina, the Venevian is correlated with the Brigantian in Western Europe. The Tarusian-Protvian interval contains diverse fusulinid and conodont assemblages, but few forms suitable for international correlation. FADs of the zonal conodont species Adetognathus unicornis and Gnathodus bollandensis at several metres above the Protvian base suggest correlation of the entire Zaborie Group and may be the basal Protvian to the Pendleian. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The basin of Lake Kotokel, located along the eastern shore of Lake Baikal, Russia, has attracted several scientific projects to investigate the climate, vegetation and lake history throughout the Late Pleistocene and Holocene. However, little was known about its basin structure and sediment architecture. Echo sounding and 3.5 kHz single frequency sub-bottom profiling were used to decipher the basin morphology and seismic stratigraphy to a depth of approximately 50 m. The bathymetric map shows a very shallow lake of 4 m mean water depth and an almost flat lake bottom. A distinct elongated small-sized depression of up to 12 m water depth between the north-western coast and a small island developed along an NW-SE-oriented fault line. A total of 46 km of seismic profiles crossing the lake along 12 transects shows that the bottom sediments consist of three different facies, which accords to previously analyzed core sequences. Several distortions of sediment layers at various sites indicate tectonically induced impact, which resulted in up to 3 m vertical offsets of sediment packages at local sites. The offsets indicate a probably still active fault along the western shoreline of the lake. Soft gyttja of the upper 6 m does not show distortions and may have obscured potential younger tectonic activity. The sediments date to the Late Pleistocene. Small updoming features along the boundary between layers I and II may be assigned to degassing processes or to seismic activity. River channel fills along the north-eastern coast are indicative of a lower lake level prior to 15 ka BP. The sediment stratigraphy indicates that suitable coring sites for paleoclimate studies are only located in the southern part of the basin where almost undisturbed sediments can be expected. [Copyright &y& Elsevier]

Abstract: In this study we analyze the importance of new magnetostratigraphic data on the Nordvik section for solving the problem of detailed Tethyan–Boreal correlation around the Jurassic–Cretaceous boundary with a special emphasis on the aspects of interpretation of the paleomagnetic data in magnetostratigraphic studies and the need for the integrated (paleontological and paleomagnetic) approach to recognition of the base of the Berriasian. [Copyright &y& Elsevier]

Abstract: The results of this study were used to identify a reversed polarity magnetozone, referred to as M17r, in Berriasian sections of the Nordvik Peninsula (northern East Siberia) within the normal polarity magnetozone (M18n) from previous studies. The new magnetozone embraces the Volgian–Ryazanian boundary (Chetaites chetae/C. sibiricus zonal boundary). It was also found that the former magnetozone M17r at Nordvik, which includes the C. sibiricus/Hectoroceras kochi zonal boundary should correspond to magnetozone M16r. Using magnetostratigraphic and biostratigraphic criteria proves that the Boreal C. sibiricus Zone is correlated with at least the major part of the Tethyan Tirnovella occitanica Zone, and the Boreal H. kochi Zone is correlated with the lower part of the Malbosiceras paramimounum Subzone of the Tethyan Fauriella boissieri Zone. [Copyright &y& Elsevier]

Diatom algae from the Eocene sediments of the marine Cenozoic section in the Il'pinskii Peninsula, northeastern Kamchatka, are studied. The taxonomic composition of the diatom assemblage is characterized, including rare representatives of oceanic plankton. Correlation with planktonic foraminifer associations found in the section indicates a Middle Eocene (Lutetian) age for the diatoms. These are the first records of Eocene diatoms from the northwestern Pacific rim for which such a correlation has been achieved. [ABSTRACT FROM AUTHOR]

This work presents results of complex research (palynological, macro- and microfaunistic, and paleomagnetic) of Upper Cretaceous deposits, opened by borehole no. 8 in the Russkaya Polyana District (the southern margin of the Omsk Depression, Southwestern Siberia). The paleontological data obtained allowed us to establish the age of deposits. Based on dinocysts, nannoplankton and spore-pollen complexes, the section of borehole no. 8 has been divided into Pokur, Kuznetsovo, Ipatovo, Slavgorod, and Gan'kino Formations. This work gives data on the composition of zonal palynomorphs, nannoplankton, and microfaunistic complexes. Based on the complex data obtained, the magnetostratigraphic section of Upper Cretaceous deposits has been developed. The section consists of three magnetozones: normal and two reversed polarity magnetozones. The Pokur, Kuznetsovo and Ipatovo Formation (Cenomanian-Santonian) belong to the long normal polarity magnetozone; the Slavgorod and Gan'kino Formations (Campanian-Maastrichtian), separated by a stratigraphic break, belong to reversed polarity magnetozones. The magnetostratigraphic section has been correlated with the general magnetostratigraphic and magnetochronological time scales. [ABSTRACT FROM AUTHOR]

Abstract: The presence of one of the oldest records of polycystine Radiolaria in the Lower Cambrian sedimentary sequence of the Ak-Kaya section (Gorny Altai) requires a biostratigraphic dating. The trilobites found recently a few tens of meters below the radiolarian-bearing level belong to Calodiscus resimus Repina, Serrodiscus fossuliferus Repina and Alacephalus aff. contortus Repina; they suggest that this part of the Shashkunar Formation can be correlated with the lower part of the Botomian stage. The absence of eyes in the two former species suggests a mode of life buried in the fine pelagic sediments. Indications of the presence of a strongly developed musculature on the third species point to a palaeoenvironment characterized by a relatively high hydrodynamic regime. [Copyright &y& Elsevier]

The Maastrichtian Koryak flora from the Amaam Lagoon area is comprehensively studied with reference to available data on the stratigraphy of the study area and age assessment of the flora-bearing deposits. In the Koryak flora 32 species of plant fossils are identified and systematically described in the work. The established traits of the Koryak floristic assemblage are used to correlate it with the other assemblages close in age from different localities of Northeastern RNortheastern Russiaussia and Alaska. The results of correlation and taxonomic revision of plant fossils from the upper part of the Prince Creek Formation, Northern Alaska show that in the Anadyr-Koryak and Northern Alaska circum-Pacific regions the Koryak stage of flora development and the respective phytostratigraphic horizon (upper Maastrichtian-Selandian), of key significance for interregional correlation of continental deposits, are distinguishable. Floristic changes recorded in the northern circum-Pacific regions across the Cretaceous-Paleogene boundary suggest that the evolution of vegetation was gradual, controlled by climatic change, evolutionary factors and plant migration. These results are inconsistent with the postulated global significance of the ecological crisis at that time. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides an outline of the lithological characteristics, microfaunal (radiolarian) biostratigraphic ages, and structural and tectonostratigraphic framework of various pelagic chert/terrigenous sedimentary successions of the Nadanhada–Bikin terrane that occur within a Jurassic accretionary prism in the Sikhote-Alin Fold Belt of eastern Russia. According to the present analysis of the available data on radiolarian and conodont microfaunal assemblages, the biostratigraphic ages of several transitional layers of pelagic chert/terrigenous sedimentary rocks that occur within various tectonostratigraphic slices of the Nadanhada–Bikin terrane, are Pliensbachian, Bajocian, and Oxfordian–Tithonian. These results indicate that the Nadanhada–Bikin terrane is composed of at least three specific age fragments of a primary sequence of sedimentary cover that once overlay the paleooceanic plate from which this terrane is derived. Therefore, it is established that the formation of the Nadanhada–Bikin terrane involved the structural emplacement of Jurassic oceanic-crust-derived tectonostratigraphic (volcanosedimentary) complexes of at least three different ages into the Jurassic accretionary prism of the Sikhote-Alin Fold Belt. [Copyright &y& Elsevier]

The thorough study of the Upper Triassic reference section located at the Tikhaya River in the central part of Kotel'nyi Island and characterized by uniform clayey lithology and containing diverse cephalopod, molluscan, and radiolarian assemblages made it possible to specify its structure and paleontological characteristic and establish for the first time the upper Anisian Sirenites yakutensis Zone. It is shown that different Late Triassic faunal groups are represented by mixed dominant Boreal and subordinate Tethyan elements. Such proportions are observable through the entire section beginning from the lower Carnian to upper Norian layers. The peculiar taxonomic composition of Late Triassic radiolarian and cephalopod assemblages provides grounds for attributing the region to an autonomous paleobiochore (New Siberian subprovince). The occurrence of both Siberian and Canadian elements in the Late Triassic faunas emphasizes the specific position of this paleobiochore determined by wide connections between basins at that time. [ABSTRACT FROM AUTHOR]

This work discusses the complex characteristic of the Upper Cretaceous (Turonian-Lower Maastrichtian) section recovered by two boreholes in the southern part of the Volgograd region (right side of the Volga River) in the Gremyach'e potash deposit. Lithological and paleontological data (benthic foraminifers, radiolarians, and dinocysts) suggest several lithological-facies and biotic reorganizations. The analysis of the distribution of these microfossils through the section allowed the ages of the Zakharovo Group, Mozhzhevelovyi Ovrag, Mezino-Lapshinovka, Pudovkino, Zarya, Nalitovo, and Bereslavka Formations to be specified. Benthic foraminifers characterize zones of the Upper Cretaceous high-resolution scale available for the East European Platform and local (facies) units, while radiolarians and dinocysts reveal stratigraphic units in a bed rank. Using complex paleontological characteristics (benthic foraminifers, radiolarians, dinocysts), the defined biostratigraphic units are correlated between each other and with their counterparts in neighboring and remote regions of different paleobiogeographic regions and provinces. The Upper Cretaceous biostratigraphic scale is supplemented by the first defined dinocyst and radiolarian biostratigraphic units of the East European Platform. The new data provides evidence in favor of a three-substage division of the Campanian Stage instead the two-substage system presently accepted in Russia. It is shown that the traditional position of the lower boundary of the Maastrichtian Stage in the East European Platform is close to that of this boundary in the Standard Stratigraphic Scale. Some aspects of environmental and biotic evolution in the Volgograd region through the Late Cretaceous Epoch are considered. [ABSTRACT FROM AUTHOR]

Abstract : The Cambrian section of the western limb of the Chekurovka anticline was studied, with layer-by-layer collection of animal fossils. This permitted us to refine the biostratigraphic division of this section. Four biostratigraphic units (beds) with small shelly fossils were identified: Lapworthella tortuosa, Lapworthella bella, Mobergella radiolata, and Rhombocorniculum cancellatum. They characterize most of the Tommotian and Atdabanian Stages of the Lower Cambrian. The Lower Tyuser Subformation and the Sekten Formation were constrained by small shelly fossils for the first time. Numerous trilobite finds helped to reveal intervals correlating with the Delgadella anabara–Nevadella and Judomia–Uktaspis (Prouktaspis) Regional Zones in the upper Atdabanian. The upper Sekten Formation (black shales) forms the Kuonamka Formation. Within this interval, the following trilobites were found: Triplagnostus gibbus, Tomagnostus sibiricus, Pseudanomocarina sp., Eodiscus oelandicus, Paradoxides sacheri, and Ptychagnostus aff. atavus. They are widespread in the vast territory of the eastern Siberian Platform, within the Kuonamka Formation. Also, Korobovia khorbosuonica, Charaulaspis postprimus, and Hebediscus convexus trilobites were observed, which had been found earlier in the Khorbosuonka River section (Olenek uplift). This permits a detailed correlation between these localities. Similarity was observed between Triangulaspis annio trilobites and young Charaulaspis. This casts doubt upon the fact that the first Triangulaspis annio finds in the northeastern Siberian Platform belonged to the upper Atdabanian. [Copyright &y& Elsevier]

This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to cristatus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4-MN6 zones. The combination of litho- and conodont biofacies supports the distinction between the Sierra Negra and Renanué Subfacies. Conodont biofacies for the studied interval are partially close to the ones from the Compte Subfacies, but lithofacies are clearly different. This faunal similarity fosters accurate correlation between subfacies and stimulates further research aiming at Devonian Pyrenean basin(s) reconstruction. Additionally, this faunal sequence permits direct comparison with regions located in northern Gondwana and in the Russian platform for part of the interval. Comparison with Laurasia, mainly with the Northwest Territories of Canada and the north-western United States, is also provided. Some taxa are also common with eastern and central Asia (China, Siberia, Tadzhikistan, Afghanistan), Australia and western USA (Nevada). [ABSTRACT FROM AUTHOR]

New data on the stratigraphy, structure, isotopic age, geochemistry, and geodynamic characteristics of the lithotectonic complexes of the Baikal-Vitim Fold System are reported. In particular, it is shown that Middle and Upper Paleozoic rocks are widespread along with Precambrian and Lower Paleozoic sequences. The Baikal-Vitim Fold System is characterized by cyclic evolution and comprises four structural stages: Baikalian (Riphean-Vendian), Caledonian (Cambrian-Early Silurian), Variscan (Late Silurian-Early Carboniferous), and Hercynian (Middle Carboniferous-Permian). A specific set of lithotectonic complexes formed in certain geodynamic settings corresponds to each stage. According to the proposed model, the Variscan and Hercynian complexes developed under conditions of progressively changing geodynamic settings of passive (Late Silurian-Middle Devonian), Andean-type active (Middle Devonian-Early Carboniferous), and Californian-type (Middle Carboniferous-Permian) continental margins. The Middle and Late Paleozoic evolution of the Baikal-Vitim Fold System is correlated with that of the Mongolia-Okhotsk Belt (Aga paleooceanic basin). [ABSTRACT FROM AUTHOR]

Abstract: In order to meet the requirements for potential GSSPs in the Cisuralian Series (Early Permian), isotopic chemostratigraphy from the Carboniferous/Permian boundary to middle Artinskian using bulk carbonates was investigated under high-resolution biostratigraphical and new geochronologic constrains from three GSSP candidate sections at Usolka, Kondurovsky and Dal''ny Tulkas in the southern Urals, Russia. A gradually increasing trend in carbonate carbon isotope (δ13C) has been observed in the interval from the base of Asselian to early Sakmarian, which is generally consistent in timing with the increasing development of Glacial III or P1 from the latest Carboniferous to early Sakmarian (Early Permian) which prevailed in southern Gondwana. An excursion with double negative shifts in δ13C value is present around the Asselian/Sakmarian boundary in both the Usolka and Kondurovsky sections, which may have great potential to serve as chemostratigraphical marks for intercontinental correlation. The following highly positive excursion of δ13C in early Sakmarian indicates the maximium expansion of Glacial III or P1. The negative δ13C shift in the middle Sakmarian is possibly related to the quick collapse of Glacial III or P1 on the Gondwanaland. This negative shift is largely correlative with those documented in other areas of Russia, the North American Craton and South China, but further precise biostratigraphical and geochronologic constrains are neccessary to confirm this global signal. The late Sakmarian is characterized by a strong oscillation stage of δ13C, which probably indicates a complex climate transition marked by smaller alternating glacial–interglacial transitions during Glacial P2 superimposed on an overall warming trend. The sharp negative δ13C shift around the Sakmarian/Artinskian boundary at the Dal''ny Tulkus section is difficult to interpret. This is followed by long-term low values (<−10‰) during the most part of Artinskian Stage. We suggest that the deeply depleted δ13C values in the Artinskian at the Dal''ny Tulkas section might result regionally from the enhanced input of organic carbon after the melt-out of ice sheets and the subsequent degradation and isotopic refractionation of the microbial chemosynthetic processes on the buried organic matter. [Copyright &y& Elsevier]

The study of new collections from the Urdyuk-Khaya Cape (Nordvik Peninsula) made it possible to specify the taxonomic composition of belemnites from the Volgian and basal Ryazanian in northern East Siberia. Cylindroteuthis knoxvillensis Anderson, 1945, C. cf. newvillensis Anderson, 1945, and Arctoteuthis tehamaensis (Stanton, 1895) known from northern California, as well as the new species C. venusta sp. nov. and A. britanna sp. nov. are first described from the Arctic region. Belemnite stratigraphy of Jurassic-Cretaceous boundary layers is fundamentally revised, allowing a new refined version of their scale to be proposed as a Boreal standard. Two independent successions of biostratigraphic units are defined in the section interval spanning the uppermost Middle Volgian Substage to the basal Ryazanian Stage: (1) Liobelus russiensis Zone, Lagonibelus gustomesovi and Arctoteuthis porrectiformis beds; (2) Lagonibelus napaensis, Arctoteuthis tehamaensis, and Cylindroteuthis knoxvillensis zones. [ABSTRACT FROM AUTHOR]

The Jurassic-Cretaceous (Volgian-Lower Valanginian) boundary deposits in the lower reaches of the Lena River (near the village of Chekurovka and on the Cape Chucha, North Yakutia) are described bed-by-bed. The taxonomic composition of ammonites and bivalves (mainly Buchia) is determined. The species assemblages are biostratigraphically analyzed and biostratigraphic units of the bed and zone ranks are recognized based on by Buchia and ammonites. Analogues of the Buchia Zones (buchiazones) Unschensis, Okensis, Tolmatschewi, Inflata and ammonite zones Exoticus, Okensis, Sibiricus, Analogus, Mesezhnikowi and ? Klimovskiensis are established in this region for the first time. A correlation of the distinguished buchiazones with the buchiazones of the Nordvik Peninsula, New Siberian Islands (Stolbovoy Island), the basin of the Anyuy River, and Northern California is proposed. The ammonite assemblages constantly contain phylloceratids; some stratigraphic intervals also contain lytoceratids; this is probably connected with a Paleo-Pacific influence. Unlike the ammonite assemblages of the same age of the Khatanga depression, the subzones cannot be distinguished in the Sibiricus and Kochi Zones of the Lower Lena due to differences in the stratigraphic ranges of some ammonite species. Hectoroceras in the Kochi zone is very rare and Praetollia predominates here. [ABSTRACT FROM AUTHOR]

The analysis of all available data on the structure of the Bajocian-Bathonian boundary section in the outskirts of Saratov (Sokur quarry) and the taxonomic composition of its ammonites, belemnites, and bivalves revealed a continuous succession of the Pseudocosmoceras michalskii (Upper Bajocian), Oraniceras besnosovi, and Arcticoceras ishmae (Lower Bathonian) zones. In connection with the critique by Meledina et al. (2009), correlation of Bajocian and Bathonian boundary strata of the Central Russia and Northern Siberia is discussed. The inconsistency of Siberian bivalve and belemnite assemblages with Central Russian ammonite zones is explained by heterochronous invasions of different molluscan groups. [ABSTRACT FROM AUTHOR]

Abstract: The Oxfordian–Lower Hauterivian section of the Nordvik Peninsula (northern Central Siberia) is a reference for developing zonal scales for various fossil groups and improving the Boreal zonal standard. In the middle 1950s–late 1980s, it was studied extensively by geologists, stratigraphers, lithologists, and experts on various fossil groups. These studies yielded rich fossil and microfossil collections and a set of parallel zonal scales for various faunal groups. Recently, a new detailed ammonite zonation of the Oxfordian and Kimmeridgian units of this section has been proposed. These results contradict the previous biostratigraphic data on ammonites, foraminifers, and palynomorphs. In the present paper, all the biostratigraphic data on the Oxfordian and Kimmeridgian units of the Nordvik Peninsula (Cape Urdyuk-Khaya) and northern Central Siberia undergo a comprehensive analysis and comparison with those on the Boreal Realm. The ammonite-constrained stratigraphic position of the lower Upper Jurassic in the Cape Urdyuk-Khaya section is interpreted as Upper Oxfordian or Middle Oxfordian. In our view, this difference in the understanding is due to the misidentification of some Oxfordian ammonite forms. The zones based on other fossil groups (foraminifers, dinocysts) which were distinguished in the Upper Oxfordian and Kimmeridgian sections of the Nordvik Peninsula are well traceable circumarctically. Their stratigraphic position in various regions of the Northern Hemisphere is constrained by ammonites and bivalves. However, if we use the last alternative ammonite zonation of this section part, hardly explicable contradictions will appear in interregional foraminiferal and dinocyst correlations. [Copyright &y& Elsevier]

Abstract: We show the present state of the set of parallel zonal scales for the Siberian Jurassic, based on various fossil groups, and the principles of their construction. We discuss the significance of Siberian biostratigraphic scales for the Boreal zonal standard of the Jurassic units. The stratotype region for this standard must have a typical Boreal (Arctic rather than mixed) fauna. A possible candidate is Siberia (and the Arctic biochorema), which is located in the center of the Panboreal Superrealm, where the set of interrelated scales for various fossil groups is the most complete. The set of parallel zonal scales for the Siberian Jurassic is efficient for the subdivision and correlation of Jurassic units in various Arctic regions (Barents Sea shelf, northeastern Russia, Arctic Alaska, Arctic Canada). [Copyright &y& Elsevier]

Arnold, L. J., Roberts, R. G., MacPhee, R. D. E., Haile, J. S., Brock, F., Möller, P., Froese, D. G., Tikhonov, A. N., Chivas, A. R., Gilbert, M. T. P. & Willerslev, E. 2010: Paper II - Dirt, dates and DNA: OSL and radiocarbon chronologies of perennially frozen sediments in Siberia, and their implications for sedimentary ancient DNA studies. Boreas, Vol. 40, pp. 417-445. 10.1111/j.1502-3885.2010.00181.x. ISSN 0300-9483 The sedimentary ancient DNA ( sedaDNA) technique offers a potentially invaluable means of investigating species evolution and extinction dynamics in high-latitude environments. An implicit assumption of the sedaDNA approach is that the extracted DNA is autochthonous with the host deposit and that it has not been physically transported from older source deposits or reworked within the sedimentary profile by postdepositional mixing. In this paper we investigate whether these fundamental conditions are upheld at seven perennially frozen wetland sites across the Taimyr Peninsula and coastal lowlands of north-central Siberia. Optically stimulated luminescence (OSL) and radiocarbon (C) dating are used to constrain the ages of both the inorganic and organic fractions of perennially frozen deposits from which sedaDNA of extinct and extant species have been recovered. OSL and C age/depth profiles, as well as single-grain equivalent dose (D) distribution characteristics, are used to assess the stratigraphic integrity of these sedaDNA sequences by (i) identifying the presence of primary or reworked organic and inorganic material, and (ii) examining the types of depositional and postdepositional processes that have affected specific sedimentary facies. The results of this study demonstrate that even though DNA preservation and stratigraphic integrity are commonly superior in perennially frozen settings, this does not, in itself, guarantee the suitability of the sedaDNA approach. The combined OSL and C chronologies reveal that certain perennially frozen sites may be poorly suited for sedaDNA analysis, and that careful site selection is paramount to ensuring the accuracy of any sedaDNA study - particularly for 'latest appearance date' estimates of extinct taxa. [ABSTRACT FROM AUTHOR]

The stratigraphy of Paleocene-Eocene rocks based on assemblages of dinocysts, benthic and planktonic foraminifers, nannoplankton, diatoms, and nummulites was refined in the sedimentary sequence penetrated by borehole (BH) 13 in the Gremyach'e potassium salt deposit. The rocks were subdivided into local lithostratigraphic units with refined ages and more substantiated reference to the general and regional scales. In addition to formations of the Volga-Caspian region: Saratov, Kamyshin, Tsaritsyn, Mechetka and Elshanka, for the Paleogene of the southwestern Volgograd region there were used formations of neighbor regions as well: Eisk Formation (Paleocene) in the eastern Donetsk Basin and the Sergeevka, Tishki and Kas'yanovka formations (Middle and Upper Eocene) in the Voronezh Anteclise. The presence of the Oligocene in the section of the Maikop Group has been established for the first time. New biostratigraphic units based on dinocysts and foraminifers were suggested. [ABSTRACT FROM AUTHOR]

The upper Bathonian Ammonites Cadoceras perrarum Voron. and Kepplerites ex gr. rosenkrantzi Spath are reported for the first time from the western coast of Anabar Bay, loosely collected. Both ammonoids represent index species of two biostratigraphic units: the Cadoceras barnstoni Beds and Cadoceras variabile Zone. The occurrence of genus Kepplerites (Kosmoceratidae) in North Siberia is evidence in favor of the migration of that family into the seas of the Arctic region. [ABSTRACT FROM AUTHOR]

Abstract: Cave and terrace localities containing Upper Pleistocene and Holocene deposits have been biostratigraphically investigated in the mountainous part of the Southern Urals, in the latitudinal oriented valley of the Belaya River (Russian Federation). The main fieldwork was undertaken in 1999–2000. Its purpose was to save all the possible geological information before the building of the Yumaguzino reservoir. Nowadays, most of the localities described in the paper are under water. Biostratigraphical and archaeological data were studied at the same time (artefacts from the Late Palaeolitic to the Early Iron Age were found in the caves). The main characteristics of the Upper Quaternary terraces and of the cave deposits as well as the results of the paleontological investigations are given. [ABSTRACT FROM AUTHOR]

Having conducted research in the basins of the Kotuy and Medvezh'ya Rivers, the phenomenon of palaeofloods in the south-eastern part of the Taymyr Peninsula has been identified for the first time. Beginning with the sub-boreal period of the Holocene, approximately 3900 years Before Present (BP), high waters and floods have been a constant occurrence in this region. The evidences thereof are as follows: (1) an absence of plant pollen and spores in the whole 10-meter formation of sediments in the second terrace above the flood plain of the Medvezh'ya River; (2) an absence of plant pollen and spores in the surface samples taken in a larch forest with upland soil near the geological cross-section that was investigated; (3) lithology and biostratigraphy of the investigated geological cross-section; and (4) contemporary hydrological activities and processes in the Kotuy-Medvezh'ya Rivers system. [ABSTRACT FROM AUTHOR]

Abstract: Lake Baikal basin in the continental interior Asia preserved a unique continuous sedimentary archive of the late Cenozoic; large-scale regional environmental changes of the past were recorded in the composition of fossil diatom flora. Here, the Lake Baikal planktonic diatom biostratigraphy is extended over the Plio-Pleistocene transition, it includes 11 new local diatom assemblage zones (LDAZ) for the time interval 1.25–3.6Ma. The comparison of the parallel BDP-96-1 and BDP-98 drill core records allows constructing the complete diatom biostratigraphic record at the time of the inception of the Northern Hemisphere glaciations; diatom biostratigraphic zones around Matuyama/Gauss paleomagnetic reversal are correlated with individual stages of marine oxygen isotope stratigraphy. Contrary to previous assumptions, the period 2.8–2.6Ma in Lake Baikal record was characterized not by a prolonged minimum in diatom abundance but by a distinct maximum in the abundance of small-celled diatom taxa Tertiarius baicalensis and Stephanodiscus binderanus et var. hyalinus, which proliferated in the lake during the interval of relatively warm and humid climate. The Lake Baikal diatom biostratigraphic change at around 1.8Ma occurs only at a species level of the genus Cyclotella. By contrast, around 2.8–2.5Ma, spectacular appearances and extinctions occurred at a high taxonomic level of genera (including the genera of Tertiarius, Thalassiobeckia and Stepahanopsis) making the biostratigraphic changes around Matuyama/Gauss reversal more prominent. At least three distinct biostratigraphic boundaries are observed: at 2.69Ma, 2.65Ma and at 2.46Ma. None of these boundaries, however, coincides with the paleomagnetic reversal at 2.58Ma. Thus the new well-resolved Lake Baikal biostratigraphic record points to the difficulty of assigning a single ‘golden spike’ biostratigraphic boundary around Matuyama/Gauss paleomagnetic reversal in continental Asia. [Copyright &y& Elsevier]

Abstract: The present paper concerns long Upper Pleistocene loess sequences from Eastern Europe with multiple Upper Palaeolithic occupations, rich in charcoal, as well as loess sequences from Central Siberia with abundant wood remains. These complementary records have allowed establishing a high-resolution climatic sequence integrating 24 interstadial episodes between ca 42.5 and 10kyr BP. Here, we discuss the methodology of dating used to fix the chronological framework of this climatic sequence, based on a set of 240 available radiocarbon dates, mainly produced on charcoal and wood remains. Special attention is paid to the strategy of sampling charcoal and wood material in strict accordance with stratigraphy, as well as to the preparation process in the laboratory for extraction, cleaning, identification and selection of the best fragments to date. Careful stratigraphic drawing and detailed positioning of the samples for each geological layer are also considered in order to clarify the relationship of the obtained dates with respect to any sedimentary, pedological or archaeological event to be dated. The reliability and accuracy of the dates obtained from loess sequences are further controlled by the internal consistency with regard to stratigraphy. Palaeoenvironmental implications are also discussed. [Copyright &y& Elsevier]

Abstract: A new fossil microbiota yielding eukaryotic Tappania is described from the Mesoproterozoic Kamo Group of the Central Angara Basin, Siberian Craton. The assemblage also includes Valeria, Satka, Lophosphaeridium, Pulvinosphaeridium, Miroedichia, Osculosphaera, Tasmanites, Obruchevella, Glomovertella, as well as branching and anastomosing filamentous microfossils of putative fungal affinities and peculiar short trichomes, that together substantially increase the biodiversity of the Tappania Association. Stratigraphic position and geochronological constraints indicate a relatively young Late Mesoproterozoic age of the Tappania-bearing sediments. There appears to be a continuity between the Tappania Association and the Neoproterozoic microbiota, the latter being firmly rooted in the Late Mesoproterozoic. [Copyright &y& Elsevier]

Abstract: The paper presents data on Callovian foraminiferal assemblages from several wells in two localities of the West Siberian plain (Shaim oil and gas district, northwestern West Siberia, and Mykhpai field, central West Siberia). The assemblages are compared and studied in terms of space and time changes of their stratigraphy, which can make basis for a more detailed zonal subdivision as more data become available. The taxonomic compositions of the assemblages are summarized in tables for specific wells to highlight their geographic variations. [Copyright &y& Elsevier]

The Ordovician shallow-water shelf deposits rich in benthic fauna are exposed along the Russian part of the Baltic. Ladoga Klint. Graptolites occur only at some stratigraphic levels, being comparatively numerous in marls and clays and very rare in carbonate layers. Since the 19th century graptolites have been collected from exposures of the Pakerort, Hunneberg, Billingen, and Volkhov regional stages (Tremadocian.Dapingian), while in the Uhaku.Idavere stratigraphic interval (Darriwilian.lower Sandbian) rare graptolites have been found in boreholes. Up to now, only some collections have been systematically studied. On the basis of new graptolite finds, recently the Pterograptus elegans Biozone was established in the upper Aseri Stage and the Nemagraptus gracilis Biozone in the lower Kukruse Stage. Detailed sampling of the Shundorovo Formation (upper Idavere Stage) resulted in the discovery of numerous diplograptids at five stratigraphic levels, in association with various dendroids. These diplograptids were provisionally assigned to ?Archiclimacograptus antiquus lineatus Elles & Wood. A systematic description of the late Darriwilian and early Sandbian diplograptids is under preparation. [ABSTRACT FROM AUTHOR]

Abstract: We report new radiocarbon ages, pollen stratigraphy, and botanical composition of an organic sediment sequence from mountains along the northwestern side of Lake Baikal. The calendar age of the peat is ca. 9.5 kyr BP. The pollen spectra between 9.5 and 8.5 kyr ago show vegetation consisting mostly of open larch and spruce-larch forests with minor birch. The interval from 7.5 to 6.8 kyr BP is marked by broad fir spread confirmed also by the peat botanical composition. The climate inferred for the period of fir dominance combines mild winters, cool summers, thick snow cover, and abundant moisture, apparently due to more intense North Atlantic air transport. Fir percentages decrease dramatically after 6.8 kyr BP, when pines begin to spread in the Baikal watershed. The peat record bears imprint of North Atlantic cooling events identified as intervals of ice-rafted detritus deposition and low surface water temperatures. The new data allow a better insight into the regional climate and landscapes, and the reliable age model provides regional and inter-regional correlations of global change events. [Copyright &y& Elsevier]

Abstract: Various opinions on the position of the Middle/Upper Triassic boundary have been concisely reviewed. The lower boundary of the Carnian Stage is accepted at the base of the Trachyceras aon Zone. The recentmost data on biostratigraphy of boundary beds of the Ladinian and Carnian Stages of the Southern Alps, Himalayas, British Columbia, northeastern Asia, Svalbard, and Arctic Canada have been considered and critically analyzed. Using sections of British Columbia with mixed Boreal and Tethyan fauna of Ammonoidea, we compared biostratigraphic schemes of the Middle/Upper Triassic boundary interval of the Boreal and Tethyan regions. On the basis of correlations and paleontological data, the lower boundary of the Carnian Stage in Northeastern Asia is suggested to be drawn at the base of the ammonoid “Protrachyceras” omkutchanicum Zone and its equivalents in other Boreal regions. [Copyright &y& Elsevier]

Abstract: Triassic sections of the Lena lower reaches (northern Yakutia) were studied. Stratigraphy and paleontology of the Triassic deposits were refined and described in detail, and their age was constrained by different fauna groups. The first detailed local Triassic biostratigraphic scheme is reported, which includes ammonoid, nautiloid, and bivalve zones and subzones and foraminifer beds. The scheme is compared with the Canadian Triassic Zonal and Standard (International) Scales. [Copyright &y& Elsevier]

Abstract: Investigations on Late Cretaceous foraminifera and their significance for the biostratigraphy of the West Siberian Plain are presented in this paper. Correlation with data on bivalves has allowed the erection of a revised division of the Upper Cretaceous deposits into local biostratigraphical units that are correlatable with the chronozones of the general stratigraphical scale. Twelve local foraminiferal zones have been established through the section. We have designated type sections for the Lower and Upper Coniacian zones of the plain (boreholes 1r, settlement of Kamyshlovo, and 23k, Beryozovo). The rank of the Beryozovskian Horizon (a regional stage), widely known previously, was promoted to Superhorizon (a regional stratigraphical unit). The Cenomanian–Santonian foraminiferal assemblages differ considerably from those of the Campanian–Maastrichtian, and are similar to coeval assemblages from other provinces within corresponding palaeobiogeographical realms, i.e., Arctic and Boreal-Atlantic. Twenty-two assemblages have been established. They vary in their composition laterally according to facies. Zones and beds containing these assemblages are well based on benthic forms and correlate with separate stages of the General Stratigraphical Scale of Russia. [Copyright &y& Elsevier]

Abstract: [Hasegawa, T., Pratt, L.M., Maeda, H., Shigeta, Y., Okamoto, T., Kase, T., Uemura, K., 2003. Upper Cretaceous stable carbon isotope stratigraphy of terrestrial organic matter from Sakhalin, Russian Far East: a proxy for the isotopic composition of paleoatmospheric CO2. Palaeogeogr. Palaeoclimatol. Palaeocol. 189, 97–115] present highly interesting patterns in stable carbon isotopic ratios based on terrestrial organic matter from Cenomanian—Maastrichtian successions in Sakhalin Island and try to match these with carbonate carbon curves from other parts of the world. Although we agree that this approach is useful and do not doubt their methods or isotopic fluctuation results, we worry about the lack of any detailed stratigraphic scheme in the paper. Our main arguments: (1) Hasegawa et al. do not show Cenomanian/Turonian stage boundary positions in the Naiba section precisely, and, as a result, it seems that the positive spike shown at this boundary might not equate with this level but relate to the upper of two Cenomanian spikes established in Japan; (2) the definition of Turonian/Coniacian boundary is also imprecise and it is difficult to understand at what level in the Naiba section they place this boundary. As a result, it seems that the positive spike which has been shown near the middle of the Coniacian could correspond to the T—C boundary; (3) the imprecise interpretation of the Campanian/Maastrichtian boundary also causes the assumption that the negative spike, which Hasegawa et al. equate with the C—M boundary could be correspond to middle of upper Maastrichtian in the Naiba section. [Copyright &y& Elsevier]