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Turkish Journal of Earth Sciences

DOI

10.3906/yer-1207-11

Abstract

Isotope geochemistry of lacustrine carbonate represents a powerful tool to reconstruct paleoclimatic and paleoenvironmental conditions. Here, we present a comprehensive set of long-term oxygen (delta^{18}O) and carbon (delta^{13}C) stable isotope records from 5 Chattian to Burdigalian lacustrine sequences distributed over the Central Anatolian Plateau. Field relationships combined with stable isotope geochemistry indicate a relatively humid subtropic Late Oligocene climate with an environment characterized by large, temporally open freshwater lakes. Approximately during the middle Aquitanian, a 4%o-5%o increase in lake delta^{18}O values indicates changes in regional climate including more arid conditions and an increasing dominance of closed saline lake conditions in the central plateau region. This time period was also characterized by frequent climatic fluctuations such as short-lived humid periods, possibly recording the influence of seasonality, topography, and the waxing and waning of aridity. In general, relatively high Oligo-Miocene delta^{18}O lake water values within the modern plateau interior, even for the least evaporative sequences, suggest the absence of significant orographic barriers at both the northern and southern plateau margins prior to 20-16 Ma.

Keywords

Cenozoic, lacustrine carbonates, stable isotopes, ^{40}Ar/^{39}Ar geochronology, Central Anatolian Plateau, Turkey

First Page

793

Last Page

819

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