Home – Home – Jornals – Russian Geology and Geophysics 2018 number Неопубликованное

The study of the spatial distribution of individual groups of marine invertebrates in the geological past and the analysis of the dynamics of their geographical differentiation over time are of great importance both for identifying patters of their evolution and for understanding the history of marine basins. In this work, taking into account modern data on paleontology and biostratigraphy of the Boreal Triassic, the taxonomic composition and distribution of Ladinian ammonoids in different regions of the Boreal Realm are specified. Zonal correlation on ammonoids of the Ladinian deposits of northeastern Asia, British Columbia, Arctic Canada, northern Greenland, Svalbard and Franz Josef Land is carried out, a chronological basis for comparative analysis of coeval ammonoid faunas is obtained. As a result of qualitative and quantitative comparative analysis of ammonoid complexes for different phases of the Ladinian Age, it is established that northeastern Asia was constantly part of the Siberian Province of the Boreal Realm. The separation of the Canadian province of the Boreal Realm occurred at the end of the constantis phase due to the penetration of trachyceratids (genus Protrachyceras) into the paleobasins of Arctic Canada, later, starting from the maclearni phase, its area increased due to the migration of Tethyan forms into the paleobasins of Svalbard. The migrations of trachyceratids, gymnitids and lobitids into boreal paleobasins from the Tethys, as well as boreal tsvetkovitids and nathorstitids into ecotone and Tethyan paleowaters of British Columbia were caused not only by circumpolar currents, but were probably associated with the lifestyle of ammonoids and their habitation in a greater or lesser range of depths of marine basins.