Ammonites of the Collignoniceratinae subfamily in the Turonian stage (upper cretaceous) of Western Siberia and their significance for stratigraphy and palaeogeography

The presence of ammonites of the subfamily Collignoniceratinae has been established in the Turonian Stage of Western Siberia. These findings allowed us to recognize the Collignoniceras woollgari zone in the Middle Turonian of this region, as well as to recognize the peculiarities of ammonite dispersal in the Arctic and clarify the palaeogeography of the Turonian age. Based on the frequency of occurrence of Collignoniceras woollgari regulare in the boreholes in the north of Western Siberia, their penetration into the West Siberian basin through the Arctic from the Western Interiort Sea of North America is most likely. For the first time Collignoniceratinae were determined in the Upper Turonian of the Yangoda River (west of the Yenisei-Khatanga regional trough).