PLIOCENE OSTRACODS OF THE CENTRAL AND SOUTHWESTERN REGIONS OF STEPPE ALTAI

Abstract

While studying the ostracods of the upper horizons of the Pavlodar formation near Omsk, T.A. Kazmina identified a volcanic ostracod complex. A complex with characteristic species Cyprinotus vassoevichi (= Cyprinotus baturini) Schneider, Caspiocypris candida (Livental), Cytherissa bogatschovi var. plana Klein, C. hyalina Schneider, Denticulocythere iliensis Bodina, D. tuberculata Negadaev was traced in outcrops and wells of the Omsk and Cherlak Irtysh regions, in the Ishim steppe and further south to Central Kulunda. The novostanic complex correlates with the Ili ostracod complex of Southeastern Kazakhstan in terms of species composition. Later, the novostanic formation was isolated from the Pavlodara formation. In the stratotypic outcrop near the village of Novaya Stanitsa on the Irtysh River south of Omsk, the sediments are represented by dark gray and brown carbonate clays, characterized by the ostracod complex of the same name, the fauna of mollusks and mammals of the Late Miocene ‒ Early Pliocene. Deposits are known in the outcro.