Title

L.A. SHMELEVA (Institute of geology Komi UB RAS), T.YU. TOLMACHEVA (VSEGEI)

Carbonate deposits of the Upper Ordovician on the Bolshaya Kosyu River (Northern Urals): sequence characteristic and the first data on conodonts

Katian­Lower Hirnantian deposits of the Upper Ordovician on the Bolshaya Kosyu River in the Northern Urals are subdivided into three lithostratigraphic units: reef massif B. Kosyu, Yaptikshor, and Verhny Ruchei formations. The latter formation has been allocated for the first time. Detailed descriptions of the sequence and its facies characteristic are given. The first data on conodonts from the B. Kosyu River enable to determine the stratigraphic accumulation interval of the sequence, to assess the biogeographical features and biofacies confinement of the studied deposits.
Keywords: local lithostratigraphic units, facies, reefs, Upper Ordovician, Katian Stage, Hirnantian Stage, conodonts, Northern Ural, Bolshaya Kosyu River.