Upper Devonian and Lower Carboniferous Foraminiferal Facies Associations from the Melekesskian Depression

Abstract

Foraminiferal assemblages are studied in several stratigraphic levels of the Upper Devonian and lower Carboniferous deposits in borehole 1001 Trudoljubovskaya (East European Platform, Volgo–Ural region). The upper Frasnian complex corresponds to slope facies. In the middle Famennian deposits, represented by slope facies and back-reef apron facies, associations of two foraminifer zones, namely Septaglomospiranella primaeva and Eoendothyra communis, are tracked. The Tournaisian deposits, represented by carbonate slope fans, contain one association in the lower Tournaisian and two associations in the upper Tournaisian (the zones Chernyshinella glomiformis–Septabrunsiina krainica–Palaeospiroplectammina tchernyshinensis and Spinoendothyra costifera). In the upper Visean deposits, represented by formations of an open, shallow shelf, foraminifers of two zones are recognised, namely Archaediscus krestovnikovi–Endothyranopsis compressa and Archaediscus gigas. The quantitative and qualitative characteristics of the facies complexes are described.