Stratigraphy and Geological Correlation

Nanobacteria, buried in situ, were discovered in the Early Precambrian paraschists (Keivy, Kola Peninsula). It is suggested that occurrence of nanobacteria indicates that a biological factor played a role in the formation of enclosing rocks.

The Permian section situated northwest of Tabas in the Halvan Mountains is studied and fusulinids occurring in the section are described. The Chili, Sartakht, and Hermez formations distinguished in the section are separated by horizons of bauxitic laterite and belong to the Khan Group formerly ranked as a synonymous formation. Fusulinids occur at two levels in the section. The lower one confined to the Chili Formation yields the so-called Kalaktash fusulinid assemblage of the late Sakmarian age. The second late Asselian assemblage has been discovered in pebbles from conglomerate-breccia in the basal laterite of the Sartakht Formation. A brief characterization of fusulinids is presented and three new species are described. The new Benshiella genus is discriminated from the Rugosofusulinidae family. As Skinner and Wilde (1965, 1966) changed the original diagnosis of the Pseudofusulina genus, we suggest, regarding all species, which have been attributed to this genus but do not satisfy the new diagnosis, as representing the new Nonpseudofusulina genus.

A new collection of plant fossils from the Derevyannye Gory Formation of the New Siberia Island collected in 2016 was studied. Thirty species of fossil plants attributed to liverworts, ferns, ginkgoaleans, conifers, and angiosperms were identified and illustrated; 16 of these species were not previously encountered among the New Siberian flora. A new angiosperm species Dalembia (?) gracilis Herman was described. New Siberian flora is characterized by a moderately rich systematic composition, by the predominance of conifers and angiosperms, by the dominance of the large-leaved platanoids and the species of the genus Trochodendroides among angiosperms, by the predominance of dentate-margined angiosperms, by the rarity of entire-margined forms, and by the total absence of cycadaleans and bennettitaleans. The age of the New Siberian flora corresponds to the Turonian–Coniacian interval; most likely, the flora should be dated to the Turonian. Plants of the New Siberian flora experienced a warm-temperate humid climate with warm summer, mild frost-free winter, and insignificant seasonality in precipitation.

Three conodont assemblages characterizing the standard triangularis, crepida, and rhomboidea zones can be defined in lower Famennian sections of the Pripyat Trough. The defined local conodont units include the Icriodus iowaensis, Palmatolepis wolskae-Palmatolepis circularis, Palmatolepis klapperi-Polygnathus semicostatus, Icriodus divergentus, and Palmatolepis subperlobata helmsi beds. The defined conodont assemblages are correlated with their coeval standard counterparts of the East European Platform. New conodont species and subspecies are described: Palmatolepis klapperi biparapetus, Polygnathus barskovi, Po. chegodaevi, Po. semeni, Po. inaequilateralis, Polynodosus nodocostatus productus, Icriodus divergentus, I. pushkini.

The isotopic-geochronological studies of zircons from granites of the Borovoe, Makinsk, and Zhukei massifs located in the eastern part of the Precambrian Kokchetav median massif revealed that they were formed during the relatively brief period from 431 to 423 Ma ago, which allowed them to be united into the Early Silurian Borovoe Complex.

Radiolarian assemblages from the Upper Cretaceous carbonate-cherty deposits of the East European platform are analyzed. Biostratigraphic subdivisions ranked as radiolarian beds are distinguished in sediments of the Moscow syneclise, Voronezh anteclise, and the Ul’yanovsk-Saratov depression. The correlation between biostratigraphic beds established in three tectonic structures and variants of their coordination with radiolarian subdivisions in southern and northern areas of Russia are considered. The key importance of radiolarians for the subdivision and correlation of the Upper Cretaceous cherty deposits is demonstrated.

“Volcanogenic Complex” as a stratigraphic term is substantiated. Also discussed are peculiarities of the volcanic process, the nature and evolution time of the volcanic structures, the complete and incomplete volcanic cycles. Data of comprehensive geological, stratigraphic and paleovolcanologic study are used to subdivide the Kinkil’skii Formation of Paleogene volcanogenic rocks in the northwestern Kamchatka, which has undivided previously, into the Shamanka, Rebro, Bozhedomova, and Geeklen volcanogenic complexes of concurrent or different ages. As a result, two epochs of volcanism (the late Ypresian-Lutetian and late Bartonian-Priabonian) are distinguished. A hiatus separating the epochs was a time of intense scouring and leveling the landforms and of the weathering crust formation. In conclusions, some problems of the paleogeography in Kamchatka and adjacent territories are discussed.

The Jurassic rocks of the area of Kanev glacial dislocations (Central Ukraine) with the Bathonian coastal marine (lagoon) and the Lower Callovian normal marine sediments have been studied, the upper part of which was unknown to the predecessors. The zonal and infrazonal scale of the Lower Callovian of Kanev dislocations are elaborated by ammonites and include four zones, five subzones, and 14 biohorizons: Elatmae Zone (the upper part: P. elatmae and P. vasily biohorizons); Subpatruus Zone (the uppermost part: Ch. saratovensis (G. toricelli) Biohorizon); Koenigi Zone with the Gowerianum (G. metorchum and G. gowerianum biohorizons), Curtilobum (G. indigestum, G. curtilobum, and G. crucifer biohorizons), and Galilaeii (G. galilaeii, s.l. Biohorizon) subzones; Calloviense Zone with the Calloviense (S. khvalynicum and S. kiselevi biohorizons) and Enodatum (C. enodatum planicerclus, C. e. enodatum, and C. e. aeeta biohorizons) subzones. This scale is compared with those of European Russia and Western Europe. It is found that the base of the Proplanulites koenigi Zone, which was distinguished by Karitzky (1887) in the sections of the north Kanev dislocations, biostratigraphically corresponds to the base of the eponymous Zone, which was distinguished by Buckman (1913) in North Yorkshire and used in a standard scale of Europe. The ammonites of the families Cardioceratidae, Kosmoceratidae, Perisphinctidae, and Macrocephalitidae common in the Early Callovian in the East European marine basin are revised and their evolution and biogeography are analyzed. It is shown that, at the beginning of the Callovian, this vast young epicontinental basin was a “pot” of neoendemic evolution of various groups of ammonites, which migrated from Arctic, West European, and West Tethyan biochorems. The western (Dnieper–Donets) marine area of the basin, which also includes the area of Kanev dislocations, was a main way for migration of marine organisms between the West and East European paleobiogeographic provinces. New species are described: Paracadoceras vasily Gulyaev, sp. nov., Sigaloceras fundator Gulyaev, sp. nov., and S. kiselevi Gulyaev, sp. nov.

The refined Quaternary stratigraphic scale of the Cisuralian and Bashkortostan regions, approved by the Commission on the Quaternary System of the Interdepartmental Stratigraphic Committee in 2007, includes the Eopleistocene (with three superhorizons and seven horizons), Neopleistocene (with three superhorizons and 13 horizons), and Holocene (one horizon and three subhorizons). The first defined Holocene Agidel Horizon with three subhorizons, the Middle Neopleistocene Klimovka, and the Upper Neopleistocene Kushnarenkovo Horizon are correlated with the Shuvalov, Gorka, and Mikulino horizons, respectively. New names and reference sections are proposed for all the Eopleistocene units. Local formations are proposed for the horizons, whose stratotypes are located in the northern Fore-Urals. The Quaternary stratigraphic scale is correlated with similar scales of the Urals, the East European Platform, and the Lower Volga region. The scale takes into account all the available data derived from the analysis of original (sediments, faunal and floral remains), published, and archival materials, which make it possible to trace in detail the main Quaternary events that occurred in the Fore-Urals.