Stratigrafiâ. Geologičeskaâ korrelâciâ
"Stratigraphy and Geological Correlation" is the only journal that provides comprehensive coverage of the fundamental and applied aspects of stratigraphy and the correlation of geological events and processes in time and space. Articles are based on the results of multidisciplinary studies and are for the researchers, university professors, students, and geologists interested in stratigraphy and the chronological features of the word's geological record.
The journal is peer-reviewed and is included in the List of the Higher Attestation Commission for the publication of works by applicants for academic degrees. Since 2010, it has been part of the RSCI system.
The magazine was founded in 1993.
Editor-in-Chief
Aleksei B. German, Dr. Sci. (Geol.–Min.), Geological Institute, RAS, Moscow
Current Issue



Vol 31, No 3 (2023)
Articles
Vodorazdelny Granite Massif (Subpolar Urals) and Correlation Problems of the Pre-Ordovician Granitoids and Volcanic Rocks from the Northern Part of the Lyapinsky Anticlinorium
Abstract
Petrogeochemical features of the Vodorazdelny massif granites (Subpolar Urals, Lyapinsky anticlinorium) indicate these rocks are close to I-granites and were formed in suprasubduction environment. The ratios of the key elements (Rb, Ba, Th, Sr, Y, Nb) suggest that the basites of the melting slab and the fluid separated during their dehydration could participate in the granite generation. The U–Pb age of the main population of magmatogenic zircons is 593 ± 4 Ma and corresponds to the Vendian (Ediacarian). It coincides with the age of the granites from the nearby Vangyr massif (598 ± 5 Ма), as well as with the age of zircon cores from the granites of the Kozhim massif located to the north. Values of εHf(t) from –2 to 0 in magmatogenic zircons with an age corresponding to the age of Vodorazdelny granites indicate a heterogeneous source of melts. The zircons of these granites also contain ancient cores with U–Pb ages from 2200 to 700 Ma, where the values of εHf(t) from +0.8 to +13 indicate the presence of a crust component in the substrate (the substance of the ancient platform basement). Petrogeochemical and isotope-geochronological parameters of granites (and their zircons) do not confirm the validity of attributing of Vodorazdelny granite massif (and its analogues – the Vangyr and Kozhim massifs) to the Cambrian Salner-Mankhambo complex. We consider there are the possibility of separating of independent complex (about 598 Ma, Vendian?) during geological mapping. The presence in the Lyapinsky anticlinorium of several stages of granite generation (Middle Riphean–Vendian–Cambrian), accompanied by metamorphism, and complicate composition of ancient metamorphic strata from this structure basement led to varying isotopic parameters characterizing the heterogeneity of the source of melts, on the one hand, and the convergence of a number of geochemical features, on the other.



Lithofacies Peculiarities and Bionomic Specification of the Fossil Remnants Complexes of the Lower Permian in the Yuryuzan-Ai Depression in the Southern Urals (on the Example of the Mechetlino Section)
Abstract
A lithofacies and bionomic study of the boundary Artinskian-Kungurian deposits of the Cisuralian Series of the Permian system in the Yuryuzan-Ai Depression was carried out on the example of the Mechetlino section (Southern Urals). The section was a candidate GSSP of the lower boundary of the Kungurian. In terrigenous-carbonate deposits, eight lithophacial types of rocks – lithofacies – are identified. According to their combination, the section is divided into packages composed of carbonate-terrigenous flysch rocks, carbonate clastic deposits initiated by storms, and blocky underwater landslide deposits. Six ecological complexes of small foraminifera are identified, reflecting sedimentation conditions in the areas of benthic fauna denudation. The mechanisms of mixing and movement of plant remains, benthic, planktonic and nectonic fossils are indicated. A model of the formation of sedimentary complexes of the Lower Permian in the Yuryuzan-Ai depression of the Pre-Ural trough is proposed, reflecting the bionomic specificity of the complexes of organic residues on the border of the Artinskian and Kungurian stages.



Late Albian–Early Turonian Grebenka Flora of the North Pacific: Systematic Composition, Age, Distibution
Abstract
Starting from the mid-Cretaceous and in the Late Cretaceous, the landscape features of the North Pacific make it possible to divide this region into a number of territories called subregions. The earliest Cenophytic (with a significant number and diversity of angiosperms) Late Albian–Early Turonian Grebenka flora and its analogs are known only in three subregions of the North Pacific: Anadyr-Koryak, Northern Alaska and Yuk-on-Koyukuk. In the middle of the Cretaceous these subregions were represented by coastal plains and lowlands periodically flooded by the sea. Cenophytic floras populated the area of terrestrial volcanism of the Okhotsk–Chukotka subregion and the Asian continental interiors of the Verkhoyansk–Chukotka subregion later, in the Turonian–Coniacian, but Mesophytic vegetation with the predominance of Early Cretaceous ferns and gymnosperms continued to exist there at least until the Coniacian. Consequently, the invasion of evolutionarily new Cenophytic vegetation into the continental interiors of North-Eastern Asia was gradual and extended over time. This should be taken into account when studying the Cretaceous nonmarine phytostratigraphy of the North Pacific region.



Taxonomical Diversity of Cenomanian-Turonian Dinocyst in the Northern Hemisphere: Some Aspects of Paleobiogeography and Paleoclimatology
Abstract
Taxonomic typification of dinocyst assemblages was carried out on the basis of a qualitative and quantitative assessment of their generic composition for the Northern Hemisphere in the Cenomanian-Turonian time in order to identify correlation taxa. Three types of dinocyst assemblages were identified in the Cenomanian. Cenomanian dinocyst assemblages are poorly differentiated; a large number of cosmopolitan genera was identified, which is in good agreement with paleobotanical data on a very warm, humid climate. Three types of dinocyst assemblages were established for the Turonian age. The number of cosmopolitan genera of dinocysts decreases, and species endemism sharply increases in individual Turonian basins. The differentiation of assemblages increases and their correlation potential decreases. However, the identified common genera and species of dinocysts in different types of assemblages provide the possibility of interregional correlation of Upper Cretaceous deposits at the stage, substage, and, at some sections, even more detailed levels in different climatic zones.



New Spore and Pollen Data from the Upper Eocene Deposits of the Sambian Peninsula, Kaliningrad Oblast
Abstract
The article presents the results of the study of continental palynomorphs from the amber-bearing Upper E-ocene deposits in the Primorsky quarry (Kaliningrad Oblast, southeastern coast of the Baltic Sea). Three spore and pollen assemblages were identified and calibrated with the dinoflagellate cyst



Discussions
Composition and Age of the Ayanka Flora (Late Cretaceous, Santonian-Campanian) of the Okhotsk-Chukotka Volcanogenic Belt: Response to the Criticism
Abstract
The main critical remarks to the paper by M.G. Moiseeva, A.B. Herman, A.B. Sokolova entitled “On the Stratigraphic Setting and Composition of the Ayanka Flora from the Upper Cretaceous of Okhotsk-Chukotka Volcanogenic Belt, Northeastern Russia” (Stratigraphy and Geological Correlation, 2022, vol. 30, No. 4, pp. 76–99), stated by S.V. Shczepetov in his article “On the Ayanka flora from the Upper Cretaceous of Northeastern Russia” (Stratigraphy and Geological Correlation, 2022, vol. 30, No. 6, pp. 113–120), are considered. Additional arguments are given to confirm the conclusions we’ve made earlier: (1) all three taphofloras from the Obryvistaya River basin came from a single straton; it however was named differently on two separate sheets of the 1:200000 State Geological Map: the Auney Member on the northern sheet and the Makkoveyem Formation on the southern one; (2) according to the composition of the plants of these taphofloras, all of them are about of the same age and can be considered as a single Ayanka Flora; (3) the most probable age of the Ayanka Flora is Santonian-Campanian, since it is undoubtedly the most similar to the Santonian-Campanian floras of Northeastern Russia and Northern Alaska.


