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

The taxonomic composition and distribution of Boreal Carnian ammonoids from northeastern Asia and Arctic Canada have been clarified, the generic assignment of some species has been revised, and their definitions have been standardized. A qualitative comparative analysis of ammonoid assemblages from northeastern Asia and the Canadian Arctic Archipelago has been conducted for the omkutchanicum, armiger, pentastichus, and combined yakutensis and bytschkovi phases. The presence of ammonoids of the genus Boreotrachyceras in the early Carnian of Arctic Canada has been substantiated. This has allowed for the first comparison of coeval ammonoid assemblages of the omkutchanicum phase from northeastern Asia and Arctic Canada, demonstrating the commonality of the ammonoid generic composition of this time throughout the Boreal Realm. It has been established that the early Carnian ammonoid fauna of northeastern Asia differs from that of Arctic Canada by the presence of Tethyan genera (Trachyceras, Striatosirenites) and families (Arpaditidae). A comparative analysis of the ammonoid fauna of the late Carnian has been conducted for the first time, separately for the formation time of the Arctosirenites canadensis beds, equivalent to the pentastichus phase, and for the formation time of the Jovites borealis beds, equivalent to the yakutensis and bytschkovi phases. As a result, for the first time, with phase accuracy, the time of penetration of Tethyan genera into the paleobasins of the Yukon and Arctic Canada (the time of formation of layers with Jovites borealis) was determined, and the belonging of Arctic Canada to the Tethyan Realm was substantiated.