About Genesis of the Mokrovolnovakha Series Carbonate Deposits (Lower Carboniferous, Southern Donbas)

Abstract

Lithology, corals and genesis of the Lower Carboniferous carbonate deposits of the Mokrovolnovakha Series in the South Donets Basin are considered. The studied deposits are formed during three eustatic cycles. Composition of carbonate sedi ments depends on sea depth, clay content and content of magnesium, iron, and silica in sea water. Depth of sea and content of clay particles in sea water may produce either photozoic or heterozoic environment of sedimentation. At regressive phases of cycles the anoxic conditions could exist. They form favorable environment for conservation of the organic matter. Sharp changes in the lithology and fauna during Tournaisian/VisJan and Early/Late VisJan times were caused by global events. The domanic deposits of the Styla suite are considered as a result of regional volcanic event.