R. R. Gabdullin

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

Lithological–geochemical, petromagnetic, and paleoecological characteristics of the Campanian–Selandian sedimentation conditions in the Ul’yanovsk–Saratov basin

The results of a complex study of the Upper Cretaceous carbonate section in the quarry of the cement plant of the town of Sengilei (Ul’yanovsk district) are presented. The Lower Paleocene cyclic opoka member is described. The formation conditions of the Upper Cretaceous cyclic and cryptocyclic, as well as Lower Paleocene cyclic, rocks are interpreted for the first time on the basis of lithological, petrographic, petromagnetic, geochemical, and paleoecological methods. The cyclicity was formed due to dilution cycles under climate fluctuation and eustatic variations, which were caused by eccentricity cycles of the Earth’s orbit. These cycles are identified in the cryptorhythmic lanceolata sequence of the Lower Maastrichtian rocks.

Upper Cretaceous sediments in the Russian Plate: Sequence stratigraphy and Milankovitch cycles

The paper discusses integrated sequence-cyclostratigraphic analysis of Upper Cretaceous sediments based on 9 sections in the Russian Plate (the Voronezh Anteclise and the Ulyanovsk-Saratov Basin). Tracts (transgressive and highstand) were for the first time recognized in sections of this region and compared with member-by-member subdivision, bed rhythmites, and Milankovitch cycles indicating their orders. Certain rhythmites and the Milankovitch cycles, which produced them, were tied to the Cyclostratigraphic Scale of the Upper Cretaceous sediments. Data on paleogeographic sedimentation environments, such as sedimentation depth, temperature, sedimentation rate, etc. and paleocoenoses are presented and paleogeographic models of rhythmic structure formation were reconstructed.

The Structure and Formation Conditions of the Bedenekir Formation Deposits (Thithonian Stage) of Mountainous Crimea

The composition and origin of the Bedenekir Formation deposits of Mountainous Crimea are detailed on the basis of our work results and analysis of both published and unpublished data.

Lithogeochemical characterization of depositional environments in the Crimean-Caucasian trough during the Early Jurassic-Aalenian (Kacha Uplift and Krasnaya Polyana)

This study presents the first results of the comparison of depositional environments in the Crimean and Caucasian regions of the Crimea-Caucasus trough during the Early Jurassic and Aalenian using lithological and geochemical methods. In this study we proposed new models for variations of temperature, salinity, and bathymetry in the Early Jurassic and Aalenian.

Astronomo-climatic cycles in the sequence of Upper Cretaceous sediments of the Saratov Volga Region

The composition and genesis of the cyclic sequence of Upper Cretaceous sediments near the town of Volsk (Saratov Region) were first investigated using a series of analytical methods. The results were statistically processed using methods of manual counting, as well as spectral and wavelet analyses. Elementary formation cyclites and cyclic variations in several parameters are correlated with astronomo-climatic Milankovitch cycles.

Lithological-Stratigraphic Characteristics of the Aptian- Cenomanian Sediments of the Abkhazian Zone of the Western Caucasus

For the first time, a complex lithological-stratigraphic and facial study of the Aptian-Cenomanian sediments of the Abkhazian zone of the Northwestern Caucasus was carried in sections of the Mzymta and Khipsta river valleys. As a result, the areas of distribution of potential oil-source rocks in these sediments, which correspond to the events of the OAE-1 and OAE-2 global paleoecological crises, oil reservoir rocks and rocks-caps were defined.

A High-precision planetary stratigraphic correlation of sedimentary Phanerozoic sequences using a combination of methods of event, paleomagnetic, sequence and cyclic stratigraphy

For the first time a high-precision planetary stratigraphic correlation of Phanerozoic sedimentary marine and continental deposits on the level of mark beds and members was produced, using a combination of methods of event, paleomagnetic, sequence and cyclic stratigraphy. Schemes of diachronism of biostratigraphic zones for the Late Maastrichtian are proposed.

Sequence-stratigraphic approach during engineering-geological works

For the first time the correspondence between engineering-geological elements (EGE) and sequence tracts is established. The sequence-stratigraphic approach allows us to upgrade archival data, determine levels of distribution of solid and weak rocks to predict areas of development of karst cavities and possible slippage of drilling tools, as well as to optimize the sampling process.

A paleogeographic model of a Cenomanian-Turonian anoxic event in Central and East Black Sea Regions

The paper presents the sedimentological and geochemical characteristics of the Cenomanian-Turonian oceanic anoxic event (OAE-2) based on eight sections in the Central and East Black Sea Regions. A series of paleogeographic models of the OAE-2 is suggested based on Crimean and Caucasian sections.