MOLLUSCAN ASSEMBLAGE AND PALEOECOLOGY OF LOWER MIOCENE SEQUENCES OF MUNZUR MOUNTAINS (EASTERN ANATOLIA, TURKEY)

Abstract

The research subject is the Miocene aged units that located in the Munzur Mountains at the Ovacık district of the Tunceli province. There is a continuous sediment deposits from Paleozoic to Cenozoic at the Munzur Mountains. The neritic limestones of the Miocene Başpınar formation outcropping in the Ovacık district are rich in fossil groups of gastropods and bivalves. In this study, 336 samples from the Başpınar formation have been evaluated. Seven species of Gastropoda (Globularia carlei, Granulolabium plicatum, Granulolabium (Tiaracerithium) thiarella, Tympanotonus margaritaceus, Terebralia subcorrugata, Nassarius erunalae, Cerithium vulgatum,) and four species of Bivalvia (Cardita rusticana, Anadara aquitanica, Cubitostrea digitalina, Ostrea lamellosa) were identifi ed. One more species of Bivalvia was identifi ed by using open nomenclature (Chlamys sp.). The studied fossil assemblage of the Başpınar formation indicates a lower Miocene age. Furthermore, for the fi rst time in this study, paleoecological species diversity is calculated by using the Simpson, Shannon-Weaver, Epilou and Margalef indices for the locations where the fossils were collected. Numerical results are obtained by comparing bivalves and gastropods. According to these results, the Gastropoda specimens shows higher dominance (Simpson index D = 0,82), higher species diversity (Shannon-Weaver index H = 2,53) and higher species richness (Margalef index M = 1,23) when correlated with Bivalvia specimens. The Epilou index value (Ep = 0,9) gives the result that the species numbers in the gastropods are approximately equal to each other.