Evaluation of Cretaceous Hinterland Weathering and Climate in the Sichuan Basin, SW China

Cretaceous is characterized by high atmospheric CO2 concentration and a resultantly high temperature. Thus, the Earth system, which operated during the greenhouse condition, can be deduced by the investigation of the paleoclimate during the Cretaceous. However, information of paleoclimate from continental inland-basins is scarce compared to that from continental margin marine-basins. In this research, the changes of weathering condition through the whole Cretaceous Period were reconstructed by analyzing the whole-rock chemical composition and clay mineral composition of mudstone samples collected in the Sichuan Basin, SW China. The reconstructed paleoweathering intensity positively correlates with paleotemperature estimate, indicating that Cenomanian-Turonian stages were climatic optimum in the Sichuan Basin as well. Furthermore, the result suggests a Cenomanian-Turonian extremely high amplitude humidity fluctuation.