title: Mid-Cretaceous carbon cycle perturbations and Oceanic Anoxic Events recorded in southern Tibet.
abstract: The organic carbon isotope (δ13Corg) curve for ~1.7-km-thick mid-Cretaceous strata of the Chaqiela section in Gamba area, southern Tibet is presented in this study. C-isotopic chemostratigraphic correlation combined with biostratigraphic constraints show that the Chaqiela section spans early Aptian through early Campanian period, and that almost all of the carbon cycle perturbations and Oceanic Anoxic Events during the mid-Cretaceous period are well recorded in the continental margin area of the southeastern Tethys Ocean. Significantly, two levels of methane-derived authigenic carbonates were identified at the onset of OAE1b near the Aptian-Albian boundary. We suggest that an increase in methane release from gas hydrates, potentially driven by sea-level fall and bottom water temperature increase, may have contributed to the large negative δ13Corgexcursions and global warming during OAE1b.
authors.affiliation: School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Kefan
authors.initials: K
authors.lastname: Chen
authors.affiliation: School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Dongping
authors.initials: D
authors.lastname: Hu
authors.affiliation: LPS, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jingeng
authors.initials: J
authors.lastname: Sha