卷 33, 编号 1 (2025)

Almost the entire Cambrian interval was uncovered in the Khantaysk-Sukhotungusskaya-1 well. Five Formations have been established in the well: Chopkо, Ust-Brus, Shumnaya, Krasnoporozhskaya, Sukharikhа. Their deposits belong to the lower Tukalandian, Mokuteian and Omnian Region Stages of the Upper Cambrian (corresponding to the lower part of the Aksaian Stage and the Saksian Stage), to the Glyptagnostus stolidotus Zone, Layers with Tomagnostella sulcifera, Layers with Lejopyge, Layers with Anomocarioides, Layers with Linguagnostus of the Middle Cambrian and Layers with Pagetiellus porrectus of the Lower Cambrian. The G. stolidotus Zone established in the well is a paleontological subdivision directly underlying the stratotype of the Omnian Region Stage, which is located in the natural section of the Chopko River. Five new Middle Cambrian trilobite species have been found: Ammagnostus minutus sp. nov., Parasolenopleura siberica sp. nov., Onchonotellus arealis sp. nov., Pseudanomocarina falcata sp. nov., Toxotiformis tchopkiensis sp. nov.

The results of comparative morphological and ontogenetic analyzes of the ostracods Bathoniella Tesakova (East European Platform (EEP) and Northern Germany, Bathonian–lower Callovian) and Parabathoniella Tesakova (Scotland, lower–middle Bathonian) suggest their origin from representatives of the genus Glyptocythere Brand et Malz with reticulate sculpture (Europe, Bajocian–Bathonian). West European Parabathoniella originates from G. comes Br. et Malz, while East European Bathoniella originates from G. tuberosa (Khabarova). Both ancestral taxa are derived from the West European G. concentrica Br. et Malz, which in the late Bajocian migrated to the EEP with the formation of allopatric species G. tuberosa. According to the priority rule, the replacement name G. pseudotuberosa Tesakova, nom. nov. was proposed for the species G. tuberosa Br. et Malz from the lower Bathonian of Germany.

The development of sculpture and linear dimensions in the lineage of reticulate Glyptocythere demonstrates a complete cycle of morphogenesis with paedomorphosis and magnification in Bajocian species and subsequent gerontomorphosis and minification in Bathonian representatives and their descendants Bathoniella in the Bathonian and early Callovian.

The stratigraphic closure of successive species made it possible to establish new lineage zones in the EEP: G. tuberosa in the terminal upper Bajocian–lower Bathonian (Michalskii–Besnosovi zones), B. prima in the terminal lower Bathonian–upper Bathonian (Ishmae Zone–lower part of the Calyx/Infimum Zone), B. milanovskyi in the upper Bathonian (presumably the upper part of the Calyx/Infimum Zone)–lower Callovian (Elatmae Zone), B. paenultima in the lower Callovian (Subpatruus Zone, biohorizons C. surensis, C. subpatruus, C. uzhovkensis) and B. ultima in the lower Callovian (Subpatruus Zone, Ch. saratovensis biohorizon–Calloviense Zone). Additionally, the B. milanovskyi Zone is distributed in Northern Germany. The species Parabathoniella elongata (Wakefield) from the lower and middle Bathonian of Scotland appears to have been the only member of the West European genus. Its homologous acquisition of bathoniella sexual dimorphism at the same time as B. prima Tesakova allows to draw a pan-European correlative level based on the first appearance of these species in the chronicle.

For the first time, magnetostratigraphic data have been obtained for the Klyuchevskaya member and the lowermost of the Lower Syzran subformation, which make up the lowermost Paleocene (Danian stage) in the north of the Volga Right Bank region near Saratov. In the stratotype section of the Klyuchevskaya member near the village of Klyuchi and in the section near the village of Tyoplovka, magnetozones were identified as the analogues of chrons C29n, C28r and C28n, due to which the Klyuchevskaya member can be compared with zones NP2–NP3 for calcareous nannoplankton, estimates of the sedimentation rate and time of sediment formation were obtained. Based on the results of a detailed magnetostratigraphic correlation of sections, with the use of geochemical data, the presence of differentiated tectonic movements at the beginning of the Paleocene in the study area was substantiated, and based on the anisotropy of magnetic susceptibility, an assumption was made about a gentle slope of the bottom of the Early Danian basin to the southwest.