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The Jurassic-Cretaceous boundary in Boreal Russia : radiolarian and calcareous dinoflagellate potential biomarkers

Vishnevskaya V. S.

Geological Quarterly

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2017

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Vol. 61, No. 3

641--654

EN

The International Berriasian Working Group (ISCS) suggested primary and secondary marker “datums” to fix the basal Berriasian boundary and thus to detine the Jurassic-Cretaceous boundary (Wimbledon et al., 2011, 2013). Two primary markers Calpionella, as well as calcareous nannoplankton, are practically unknown in the Boreal Realm. Testing and calibration of these markers, as well as of fossils of radiolarians and other signals, in the most complete sections, were declared as an important task for the near future. In the Tethys, the Jurassic-Cretaceous boundary based on radiolarians falls inside zone UAZ 13 of Baumgartner et al. (1995), whereas in the palaeo-Pacific it corresponds to the boundary between zones 4 and 5 of Pessagno et al. (2009), and in boreal Siberia it probably falls between the biohorizons of Parvicingula haeckeli and P. khabakovi. The radiolarian events at the Jurassic-Cretaceous boundary in the boreal successions of Russia can be proposed to be used as an additional biomarker to help develop new integrated boundary criteria. Thus, as the first appearance of the zonal species Calpionella alpina, which defines the Jurassic and Cretaceous boundary, coincides with the first occurrence of the calcareous dinocyst zonal species Stomiosphaerina proxima (Reháková, 2000), it is logical to propose a calcareous dinoflagellate, widely represented in the Upper Jurassic-Lower Cretaceous Bazhenovo Formation of Siberia, as a secondary marker.

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Ammonites and ammonite stratigraphy of the uppermost Jurassic (Tithonian) of the Owadów–Brzezinki quarry (central Poland)

Martja B., Wierzbowski A.

Volumina Jurassica

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2016

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Vol. 14, no. 1

65--122

EN

The Tithonian ammonite succession at the Owadów–Brzezinki quarry, central Poland shows the presence of Subboreal ammonites of both NE European (“Volgian”) and NW European (“Bolonian–Portlandian”) affinity, making possible the correlation between the relevant ammonite subdivisions. The former are represented by Zaraiskites – Z. regularis Kutek and Z. zarajskensis (Michalski) as well as an early form of Virgatites – V. gerassimovi Mitta which enable the recognition of the upper part of the Scythicus Zone (the Zaraj¬skensis Subzone) and the lower part of the Virgatus Zone (the Gerassimovi Subzone) of the “Middle Volgian”. The latter are represented by Virgatopavlovia, which enables the correlation with the Fittoni Zone of the uppermost “Bolonian”, and by still younger assemblage of small-sized virgatitids – such as V. pusillus (Michalski), showing similarity to Progalbanites albani (Arkell) of the Albani Zone of the lowermost “Portlandian”. The new species established include: Zaraiskites lewinskii sp. nov. which represents a new member of the virgatitid lineage linking an older Z. pommerania (Arkell) with younger small-sized Virgatites, as well as two species of the genus Virgatopavlovia – V. janeki sp. nov. and V. dembowskae sp. nov. The appearance of ammonites of NW and NE European affinity in central Poland resulted from the opening of the new sea routes possibly related with tectonic activity in northern European areas at the transition from Early to Late Tithonian.

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New stratigraphic and isotope data on the Kimmeridgian-Volgian boundarybeds of the Subpolar Urals, Western Siberia

Rogov M. A., Price G. D.

Geological Quarterly

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2010

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Vol. 54, No 1

33-40

EN

A review and new data regarding the ammonite faunas and biostratigraphy of the uppermost Kimmeridgian-lowermost Volgian of theSubpolar Urals are presented. The combined ranges of almost all ammonite genera in the lowermost Volgian of the Subpolar Urals supports the traditional point of view regarding the equivalence of the Magnum Zone with the two lowermost Bolonian Zones and with thebulk of the Klimovi Zone. This stratigraphic interpretation permits the stable isotope data (carbon and oxygen) derived from associatedbelemnites to be presented in context. The isotopic records from the belemnites suggest that the lower Volgian sediments of the YatriaRiver, Subpolar Ural Mountains were deposited in a warm marine environment consistent with a warm high latitude scenario. If reducedsalinites are invoked apparent temperatures are lowered by ~5°C, but still remain well above freezing and are relatively warm comparedto some recent modelled estimates of Late Jurassic ocean temperatures.

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The foraminiferal assemblages of the uppermost Kimmeridgian-Volgian succession of Western Siberia and their correlation potential 157 INTRODUCTION During the last few decades, the stratigraphy of the uppermost Jurassic-lowermost Cretaceous (scope, sequen

Podobina V., Gabysheva E., Tatyanin G.

Volumina Jurassica

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2009

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Vol. 7, no. 1

157-172

EN

The present study summarizes the data on the continuous stratigraphic sequence of foraminiferal assemblages from the Volgian deposits of the south-east of Western Siberia. Microfaunal analyses of 650 core samples from 18 boreholes of Volgian deposits were performed. Eighty two foraminiferal species, identified from the samples, were combined into the Volgian assemblages. On the basis of these assemblages, four biostratigraphic units were established in the range of foraminiferal zones and foraminiferal beds with characteristic species. These biostratigraphic units correspond to the upper part of the Kimmeridgian/ lower part of the Volgian, the Middle Volgian (lowermost and uppermost beds), and the Upper Volgian. A detailed biostratigraphic analysis of the Volgian beds was carried out, which enabled a correlation scheme to be developed for major regions of Russia. West-Siberian foraminiferal assemblages were correlated with those of Europe and North America within the Panboreal Superrealm. The species composition of foraminiferal assemblages was analyzed, and correlatable species ere established. This provided an opportunity to correlate coeval strata from Western Siberia, East European (Russian) Platform, northern territories of Siberia and Arctic Islands, Canada, Spitsbergen and England. The possibility was established for correlating Volgian-Tithonian deposits of the Panboreal and Tethys-Panthalassa Superrealms through the Dnieper-Donets Basin where faunas of both southern and Boreal-Arctic types are met.

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Upper Jurassic dinoflagellate cyst biostratigraphy of the Shaim petroleum-bearing region (Western Siberia)

Trubicyna A., Ilyina V.

Volumina Jurassica

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2006

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Vol. 4, no. 1

216-217

EN

The results of palynological analysis of the sediments of the Abalak Formation from five boreholes in the Shaim petroleum-bearing region (northwestern part of Western Siberia) allow determining the Late Jurassic (Oxfordian to Volgian) age of the deposites in question. The study of taxonomic composition and stratigraphic distribution of dinoflagellate cyst as well as spores and pollen grains, acritarchs and prasinophyts have provided the basis for a local biostratigraphic subdivision of these deposits. The geosequence of five dinozones has been defined.

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The Volgian Stage and Jurassic/Cretaceous boundary in the Panboreal Superrealm

Zakharov V., Rogov M., Kiselev D.

Volumina Jurassica

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2006

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Vol. 4, no. 1

224-226

EN

Correlation between the Volgian and Tithonian stages has been the subject of controversy for many decades. But comparison of the zonal succession within the single stage also encounters some problems. Here we propose new correlation between the Volgian Stage and Portlandian Stage. The correlation chart shows possible relations between the Volgian and basal Cretaceous zones and these of the different provinces (Fig. 1). Important for correlation records of ammonites are as follows: 1. Paracraspedites sp. and Epivirgatites cf. variabilis Shulg.occur together with E. lahuseni (Nik.) and E. cf. nikitini (Mich.) in Gorodoschi (Kiselev & Rogov 2005). 2. Laugeites sp. nov. aff. parvus Donovan occurs with Subcraspedites sowerbyi Spath, S. cf. preplicomphalus Swinn. in Gorodischi (Kiselev & Rogov 2005). 3. Craspedites okensis (d'Orb.) appears in Russia, Svalbard and Siberia nearly simultaneously. 4. Laugeites cf. planus Mesezhn. co-occurs with Epivirgatites variabilis Shulg. in Nordvik section. 5. Epilaugeites ranges into the upper part of Variabilis Zone of the Nordvik section. 6. Laugeites sp. nov. aff. parvus Donovan is recorded together with Praechetaites exoticus Shulg. and P. tenuicostatus Shulg. in Nordvik. 7. Dorsoplanites maximus Spath and D. gracilis, typical for Subpolar Urals, are known from faunas 42 and 43 of East Greenland (Callomon & Birkelund 1982). 8. Epipallasiceras in the Albani Zone of England and French coast (Wimbledon 1984), includes so-called "Epivirgatites" forms. 9. Crendonites spp. ranges from Glaucolithus to Kerberus zones of England (Wimbledon 1984) and from Anguinus to Groenlandicus zones in East Greenland (Callomon & Birkelund 1982); ammonites close to Siberian Crendonites subleslie are known from the Glaucolithes/Okusensis boundary interval of England (Wimbledon 1984). 10. Epilaugeites vogulicus (Ilov.) was recorded in the Oppressus Zone of England; subsequent ascribing of this ammonite to Okusensis Zone by Wimbledon (1984) seems not well proved. 11. Craspedites pseudonodiger Shulg. occurs in the Taimyrensis Zone of Siberia and in the uppermost Nodiger Zone of Kashpir. 12. Recent records of Volgidiscus in the Yaroslavl region permit to correlate this level with uppermost Volgian of Siberia and uppermost Portlandian. Existence of the detached zone with Subcraspedites above Volgidiscus is in Arctic (Mesezhnikov et al. 1983) and it appears in the basal Cretaceous of the Russian Platform (Mitta 2005) and England (Casey 1973). 13. Praetollia spp. is widely distributed in Arctic (Mesezhnikov et al. 1983) and appears in the basal Cretaceous of the Russian Platform (Mitta 2005) and England (Casey 1973). 14. The key event was a spreading of Boreal Hectoroceras from Siberia through Central Russia to England (Casey 1973) and East Greenland.

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The problem of establishing the Tithonian Stage in Western Siberia

Podobina V., Gabysheva E., Tatyanin G.

Volumina Jurassica

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2006

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Vol. 4, no. 1

205-206

EN

In 1996 the Volgian Stage was withdrawn from the General Stratigraphic Scale and replaced with the Tithonian Stage by the Resolution of the Interdepartmental Stratigraphical Committee of Russia. However, this did not solve the problem of correlation between the Volgian and Tithonian stages. The problem of identifying and mapping the Tithonian Stage within the Boreal deposits becomes unresolved. On this basis the Volgian Stage was retained in the West Siberian Stratigraphical Scale as the terminal Jurassic Stage, owing to the impossibility of the application of the new standard directly to the Boreal sections. The difficulties in comparison between the Regional Scale and the Standard one arise not only for the ammonite zones, but also in correlating the West Siberian foraminiferal zones. Numerous boreholes penetrating Western Siberia and combined studies on core samples enable tracing the continuous sequence of the Volgian foraminiferal zones and beds. The foraminiferal sequence traced through the Nyarginskian type section in the southeast of Western Siberia may serve as an example. There, in the Upper Kimmeridgian – Lower Volgian deposits, the f-beds with the Pseudolamarkina sp. Assemblage were established. The Middle Volgian Spiroplectammina vicinalis-Dorothia tortuosa F-zone was divided into two subzones: the lower Spiroplectammina vicinalis-Saracenaria pravoslavlevi subzone and the upper Dorothia tortuosa subzone The Upper Volgian deposits enclose the Ammodiscus veteranus-Evolutinella volossatovi F-zone. At the Jurassic/Cretaceous boundary, the taxonomy of benthic Foraminifera is essentially different. The phylogenetic succession of numerous foraminiferal genera during the Volgian Age indicates the integrity of the Volgian Stage. A number of genera are characteristic only for the Volgian. Benthic Foraminifera forming the basis for establishing the Upper Jurassic assemblages, and the Volgian ones in particular, showed a wide distribution in the Late Jurassic marine basins of the Boreal belt: Northern Europe (Russia and Poland), Northeast Asia, Northern America (Northern and Northwest Canada, Northern Alaska), islands of the Arctic Region and shelves of northern seas. This wide distribution of the Volgian Foraminifera resulted from the Late Jurassic transgression. The Boreal and Tethyan foraminiferal assemblages differ essentially each other in their taxonomy, which result in significant difficulties in correlation between the Volgian and Tithonian deposits of Boreal and Tethyan belts, respectively. Besides, the distinctive feature of all provinces of the Boreal belt is the absence of planktonic foraminifers or their insignificant development. The direct correlation of the Volgian assemblages is possible only within the Boreal belt, basing on the taxonomical analysis of foraminiferal assemblages and the presence of the species of correlation value. The correlation of the Volgian-Tithonian deposits of the Boreal and Tethyan belts is feasible only at the level of Lower-Middle Volgian substages and the Tithonian. We suppose that at present it is impossible to find direct counterparts of the Upper Volgian Substage.