Paleoenvironment of the Early Miocene Akyar Formation: Insights from Stable Isotope Analysis of Benthic Foraminifera

Abstract

This study presents the first stable isotope data of benthic foraminifera and discusses the paleoenvironmental conditions in Lower Miocene deposits (Akyar Formation) from the Yazıhan (N-NW Malatya) and Muşardağı (Baskil, SW Elazığ) areas located in the eastern part of the Taurus-Anatolian Platform, Türkiye. The Akyar Formation is composed of limestone, mudstone, calcirudite, and calcarenite interlayers including rich foraminiferal assemblages. They showed Aquitanian-Burdigalian (Early Miocene) in age. The foraminiferal assemblage, bivalve identified as Hyotissa hyotis, and the abundance of corals indicate a tropical to subtropical warm paleoenvironment from the inner shelf to the slope. δ18O values of foraminifera species have quite negative values between -7.99 and -0.27‰, and δ13C values are from -1.56 to +0.41‰. According to isotopic data and fossil content, paleosalinity was at the normal salinity levels. The obtained paleotemperature data from the δ18O values showed that, the Early Miocene the sea water temperature was extremely high. It is assumed that high temperatures were possibly related to the Yamadağı volcanism, starting from the late Cretaceous to the middle-late Miocene in the northern part of the study area.