Зональное расчленение сарматского яруса по двустворчатым моллюскам

E.I. Koiumdgieua, N.P. Paramonoua, L.S. Belokrys, S.V. Muskhelislwili. Zonal subdivision of the Sarmatian Stage after bivalvian molluscs. Two zonal sequences after bivalvian molluscs are separated in the Sarmatian Regional Stage in the Paratethys - in coarse sediments (sands, detritic limestones) and in pelitic sediments. The zonal sequence in coarse sediments is: (1) Mactra eichwaldi – Plicatiforma praeplicata Concurrent-range-zone (Lower Volhynian); (2) Mactra eichwaldi – Plicatiforma plicata Concurrent-range-zone (Upper Volhynian); (3) Mactra vitaliana pallasi Interval-zone (Lower Bessarabian); (4) Plicatiforma fittoni Range-zone (Upper Bessarabian); (5) Mactra balcica – Mactra bulgarica Range-zone (Lower and Middle Chersonian); (6) Mactra - Ervilia Barren-interzone (Upper Chersonian).
   The zonal sequence in pelitic sediments is: (1) Abra reflexa Interval-zone (Volhynian) with (1a) Abra reflexa – Chartocardium nigrum Concurrent-acme-subzone (Upper Volhynian); (2) Cryptomactra pseudotellina Range-zone (Lower Bessarabian); (3) Cryptomactra pesanseris Interval-zone (Upper Bessarabian); (4) Mactra timida Range-zone (Lower Chersonian). The correlation between the two zonal sequences is approximative.