Abstract:

On the basis of the oxide, calcium carbonate and organic carbon contents, and organic carbon stable isotope of the continental strata in the Turpan Basin, Xinjiang, together with the ratio of Fe³⁺/Fe²⁺, the Cretaceous/Paleogene boundary and paleoclimate during this period have been studied. Our studies have revealed that an apparent oscillation of all environmental proxies occurred near the boundary. At the terminal Cretaceous, δ¹³C_org increased significantly, organic carbon, calcium carbonate, SiO₂ and Al₂O₃  contents decreased, while at the beginning of Paleocene, the increasing of SiO₂ and Al₂O₃ contents was accompanied by the decreasing of δ¹³C_org. These changes actually reflected a cool event in the latest Cretaceous. Study of ratio of  Fe³⁺/Fe²⁺ further indicated that the temperature was low in the latest Cretaceous, which is consistent with the result derived from the organic carbon isotope.

Key words: Cretaceous/Paleogene, boundary, organic carbon, isotope, oxide, Turpan Basin, Xinjiang