Investigation of palaeotemperature changes trend in Aptian–Albian carbonate deposits of the Zagros Fold-Thrust Belt based on oxygen isotope data

In this study, geochemical (including elemental and stable isotope) data were used for study of climatic changes during the deposition of Aptian carbonate of the Dariyan Formation in the Zagros Fold-Thrust Belt. In order to study palaeotemperature fluctuations, oxygen stable isotope was used as a temperature sensitive proxy. Results of this study show an increasing of temperature at the beginning of early Aptian and two cooling episodes during late early Aptian and late Aptian in the studied deposits. Correlation of Sr/Ca ratio, carbon stable isotope values and temperature fluctuations trend in these deposits with other studies reveal that influx of carbon dioxide in atmospheric-oceanic system via sub-marine volcanism activities is main mechanism for increasing temperature. On the contrary, carbon outlet via burial of organic matter in deposits regarded as most important factor in decreasing temperature. Obtained data are in accordance with other studies and show that during deposition of the Dariyan carbonate deposits greenhouse condition was not dominated throughout the Aptian age , and cooling episodes occurred in some intervals.