Sedimentology and isotope geochemistry of early Pliocene shallow lacustrine dolomitic succession in the Baklan Basin, Southwestern Türkiye

A multiproxy study of the lower Pliocene (Zanclean) shallow lacustrine succession in the southwestern margin of the Baklan Basin (southwestern Anatolia, Türkiye) provides new insights into the paleoclimatic and paleohydrologic evolution of an extensional basin located at the top of the western Taurides mountain range in the southeastern Mediterranean region. Detailed petrographic, sedimentological, palynological and stable isotope analyses on Mg-rich carbonates were carried out on the dolomitic succession in the Sapaca locality in the basin, indicating a vegetated, quiet to slow-moving, low-gradient, perennial, alkaline shallow lake environment under warm and arid climate conditions. The stable isotopic analysis of the dolomitic carbonates exhibits a narrow range of values (-1.31<δ18O<+5.82‰ and -7.10<δ13C<-2.10‰) and the δ18O–δ13C correlation (r= 0.70) indicates a hydrologically closed lake. Two types of dolomite are identified in the studied section. Type-1 crystals formed mainly as a result of primary precipitation of dolomite in the shallow lake, whereas type-2 crystals probably indicate microbially controlled dolomite precipitation. The palynological record from Sapaca reveals that the early Pliocene paleoenvironment was dominated by steppe and open vegetation with some isolated shrubs. Similar paleoclimatic and paleovegetational conditions are observed in other Anatolian basins and in the southern Mediterranean region. Therefore, the results of this study demonstrate that the shallow lacustrine system of the Baklan Basin serves as a good analogue for understanding early Pliocene warmth and aridity in this region.