Stable isotopes of black carbon and their implications to paleoclimate in the eastern Tethys during the PETM

Abstract

The Paleocene-Eocene Thermal Maximum (PETM; ca. 56 Ma) was marked by a significant rise in global temperatures due to rapid and sustained carbon emissions. As a result of the induced warming, extreme precipitation, widespread wildfires, and enhanced physical and chemical weathering have been reported from many locations globally. However, the eastern Tethys, a key subtropical site for heat and moisture transport, has not been thoroughly investigated. In this study, we analyze the stable carbon isotopes of black carbon, a product of incomplete combustion of vegetation or fossil fuels, to assess the role of climate change in driving the perturbation to the organic carbon cycle during the PETM. The carbon isotope excursion documented in black carbon from the sedimentary record of the Kuzigongsu section in the Tarim Basin, eastern Tethys, suggests enhanced mobilization of aged petrogenic organic carbon driven by extreme seasonal precipitation during the PETM. The oxidation of petrogenic organic carbon may have acted as an additional carbon source, contributing to the sustained warming of the PETM.