The Problem of Dating the Kuyeda-Klyuchiki Section – a Unique Locality of Permian Vertebrates (Perm Region, Russia)

The Kueda-Klyuchiki locality of Permian vertebrates located in the south of the Perm Region in the Kuedinsky District was discovered in 2005 and quickly became known among paleontologists. The locality contains a rich complex of exceptionally preserved plants and vertebrates (fish, amphibians, and reptiles). Their remains are confined to limestones of various textures, which form two bone-bearing beds in the section of the quarry. However, the age of rocks remains a controversial issue. This research aims to analyze and compare various stratigraphic markers and discuss a number of existing stratigraphic inconsistencies in an attempt to arrive at a general conclusion about the age of the locality. According to geological survey data on a scale of 1:200 000, the Buraevo Sequence (Sheshmian Formation, Ufimian Stage) was identified in the territory of the quarry. At the boundary of the Sheshmian and Belebey Formations, a mineralogical “boundary” is observed, which is manifested in a decrease