L. F. Kopaevich

Cretaceous volcanic belts and the evolution of the Black Sea Basin

Deposits in southwestern Crimea that contain Late Albian, Middle Senomanian, and Middle Campanian volcanic material are described and dated. Supposedly volcanic edifices are identified in the Black Sea (the Shatsky Swell) based on seismic data. The Albian, Senomanian, and Campanian volcanic belts are reconstructed for the entire Black Sea Region. The suggestion is made that the Black Sea Basin formed as a back-arc basin that started from rifting in the Albian and finished with spreading of the oceanic crust in the Senomanian-Early Santonian.

Mesozoic to recent geological history of southern Crimea and the Eastern Black Sea region

Abstract We provide a synthesis of stratigraphic data to unravel the history of the geological evolution of South Crimea in the Mesozoic and Cenozoic. The South Crimea Orogen consists of three major mega-sequences: (1) the Triassic–Early Jurassic; (2) the Aalenian–Bathonian; and (3) the Callovian–Eocene. The Late Triassic–Early Jurassic deposits formed in the environment of a forearc basin and a remnant basin. The Aalenian–Bathonian deposits formed above subduction extension and a volcanic belt. Three main Callovian–Eocene tectonic units can be identified in South Crimea: (1) the South Crimean Shelf Basin; (2) the Sudak Deepwater Trough; and (3) the Alchak–Kaya Shelf Basin at the northern margin of the Shatsky Ridge. The Oligocene–Quaternary deposits are considered to be syn-orogenic. A description of the anticipated stratigraphic units on the Shatsky Ridge is suggested for the Middle Jurassic, Callovian–Late Jurassic, Neocomian, Aptian–Albian, Late Cretaceous–Paleocene, Eocene and Maykopian. We propose a model for the geological history of the Eastern Black Sea Basin. Graben formed during the Late Barremian–Albian at the location of the future Eastern Black Sea Basin and a phase of volcanism occurred in the Albian. The main phase of rifting and spreading of oceanic crust took place during Cenomanian–Santonian time. Supplementary material: A Google Earth kmz file of the location of the outcrops and sections is available at http://www.geolsoc.org.uk/SUP18850

Radiolaria, planktonic foraminifera, and stratigraphy of Turonian-lower Coniacian in the Biyuk-Karasu section, Crimea

The first data on the distribution of Radiolaria and planktonic Foraminifera in the section at Biyuk-Karasu River in central part of the Crimean Mountains, are presented. Based on the study of radiolarian findings, the upper Cretaceous deposits of Biyuk-Karasu section are subdivided into the following biostratigraphic units: Alievium superbum-Phaseliforma turovi (middle Turonian), Dactylodiscus longispinus-Patulibracchium (?) quadroastrum (upper Turonian), and Orbiculiforma quadrata-Patellula sp. B (Turonian-Coniacian boundary deposits). The stratigraphic interval of Alievium superbum-Phaseliforma turovi has been previously characterized by the complex of Alievium superbum-Phaseliforma sp. A (middle Turonian, Mt. Chuku section, SW of the Crimean Mountains, and middle Turonian, Mt. Ak, central part of the Crimean Mountains). Based on the study of Foraminifera findings, the following biostratigraphic subdivisions were identified: Whiteinella paradubia (lower-lower part of the middle Turonian), Marginotruncana pseudolinneiana (uppermost middle Turonian), and Marginotruncana coronata (upper Turonian). The complex of beds with Marginotruncana pseudolinneiana and Marginotruncana coronata are comparable to the deposits of zones of same name in the Crimean-Caucasian region.

The Oil and Gas Potential of the Kuma Rocks of the Bakhchisarai Region of Crimea

The oil and gas potential of the Kuma Formation of the Bakhchisarai region (southwestern Crimea) was substantiated on the basis of a lithological and micropaleontological study of the rocks of the section of the formation and geochemical (luminescent-bituminous, gas-liquid chromatographic, pyrolytic, and isotope) studies of the organic matter of the rocks. New regions for study that are favorable for the origination of the oil system in this formation were identified.

The stratigraphic setting of cretaceous volcanic rocks in Crimea and in the North Caucasus

The ages of volcanic activity in the Crimea and North Caucasus are reported in this paper. The age estimation of the described ranges is based on the results of micropaleontological analysis (planktonic Foraminifera) with account for the data on other groups, mostly Ammonites and Inoceramids. Volcanic rocks are related to the Upper Albian (Thalmanninella appenninica Zone), Lower Cenomanian (Thalmanninella globotruncanoides Zone) deposits, boundary deposits of the Lower and Middle Cenomanian (Thalmanninella deeckey Zone), and Middle-Upper Cenomanian (Rotalipora cushmani Zone). Volcanic activity was found for the Campanian Stage (Globotruncanita elevate and Globotruncana ventricosa) as well.

The composition of the sandstone from the Oligocene turbidite of the Tuapse marginal trough

The lower part of the Maykop Group sediments of the Crimea-Caucasus region were studied. Available outcrops of every structure-facies zone were examined and the sandstone composition was determined in thin sections: as a result five main lithologies were distinguished. Sharply discrepant provenance sources for the Kerch Peninsula, Sochi area, and Abkhazia for the Early Oligocene are suggested and those feeding areas are assumed to be variably remote from a sedimentary basin. An updated Rupelian (early Oligocene) palaeogeographic scheme of the Crimea-Caucasus region is proposed.

New bio- and magnetostratigraphic data on Campanian‒Maastrichtian deposits of the classical Nizhnyaya Bannovka section (Volga river right bank, southern Saratov region)

The integral investigation of the upper Campanian‒Maastrichtian section near the settlement of Nizhnyaya Bannovka (Krasnoarmeiskii district, Saratov oblast) included its detailed lithological description and the study of different organic remains (belemnites, benthic and planktonic foraminifers, radiolarian, calcareous nannofossils, dinocysts) with the analysis of their taxonomic composition and stratigraphic distribution and magnetostratigraphic (magnetic polarity and petromagnetic) properties. The belemnite findings indicate the presence of the upper Campanian Belemnitella langei Zone in the section, which comprises sediments previously attributed to the lower Maastrichtian Belemnitella lanceolata Zone. The analogs of magnetic polarity chrons 33n, 32r, and 31n (probably superposed chrons 31n and 30) are established. It is assumed that radiolarians offer the opportunity to define the middle Campanian substage by analogy with the standard (international) stratigraphic scale. On the basis of benthic foraminifers, calcareous dinocysts, and paleomagnetic data, the late Maastrichtian age of sediments previously dated back to the early Maastrichtian is substantiated. A large hiatus corresponding to the terminal Campanian‒early Maastrichtian is revealed in the section. The succession of sedimentological, biotic, and paleogeographic events is outlined for the late Campanian‒Maastrichtian interval. The obtained data make it possible to disclose paleobiogeographic connections between microfaunal communities of the Campanian and late Maastrichtian seas on the East European and West Siberian plates. It is established that the uppermost Maastrichtian sediments are enriched in extraterrestrial matter.

Tectonostratigraphy as a basis for paleotectonic reconstructions

Tectonostratigraphy deals with distinguishing megasequences and their interpretation in terms of tectonic settings. It is closely related to sequence stratigraphy and regional tectonics. Tectonosratigraphic units are distinctly displayed on seismic profiles. Examination of megasequences is a reliable tool for regional-scale research. We discuss, using several specific examples, the process of identifying tectonostratigraphic units in various types of sedimentary basins, as well as their relations to chronostratigraphic units.

The Crimean Eocene nummulite bank

Eocene nummulitic limestones represent potential reservoir rocks for oil accumulations in Central Asia, North Africa, and the Mediterranean region. Examination of their lithology and sedimentation settings is of great practical significance. This communication is dedicated to the characteristics of carbonate facies with Early–Middle Eocene nummulites developed in the Mountainous Crimea. Their best outcrops, which form a narrow band extending W–E, occur in the Mount Inkerman, Krasnyi Mak Settlement, Mount Suvlu-Kaya, Skalistoe Settlement, Simferopol City, Litvinenkovo Settlement (Zuya River), Mount Ak-Kaya, Prolom Settlement, and Nasypnoe Settlement (Feodosiya City) areas (Fig. 1). The rocks were examined with the unaided eye and under a microscope in thin sections. Their petrophysical properties were determined by analytical methods. Classification of carbonate rocks based on their primary sedimentary textures after R.J. Dunham was used when describing the rocks under the microscope [Wilson, 1980]. Based on nannofossils and foraminifers, the nummulite limestones constituting the Simferopol Formation are estimated to be late Ypreasian–early Lutetian in age [Zakrevskaya, 1993].

The Alan-Kyr Coniacian–Campanian section (Crimean Mountains): Biostratigraphy and paleobiogeography aspects

This investigation continues the study of the Alan-Kyr reference section (Central Crimea, Belogorsk Region). The zoned age difference in the stratigraphic scheme of the Upper Cretaceous in the Eastern European Platform is considered according to benthic and planktonic foraminifers, as well as radiolarians in the Alan-Kyr section. This fact can be explained based on the suggestion that stratigraphically important taxa could have appeared in Crimea several million years earlier than on the platform, where they could migrate under the great global eustatic transgression in the Early Campanian. We also considered the influence of paleobiogeographic conditions on the taxonomic composition of the zoned foraminifer complexes, both benthic and planktonic.