Terrestrial records of the Early Cretaceous paleoclimate changes in the Liupanshan Basin, NW China: Evidence from sedimentology and geochemistry

This paper reported geochemical data of the upper member of the Lower Cretaceous Liupanshan Group (Liwaxia, Madongshan and Naijiahe formations) in the Liupanshan Basin (North China) and revealed the evolution of paleoenvironment and paleoclimate recorded in the terrestrial lake. Geochemical indicators revealed a weak weathering and negligible sedimentary recycling. The provenance of the Liwaxia-Naijiahe formations were mainly felsic acidic rocks of the eastern Qilian and western Qinling areas. A series of paleoclimate proxies (such as Th/U, Rb/Sr, etc.) reveal that Liwaxia-Naijiahe formations were deposited in a semiarid- arid and anoxic paleoclimate, and the degree of aridity and paleosalinity increases from the Liwaxia to the Naijiahe period. The extensive paleoclimatic and paleosalinity changes, and organic matter enrichment recorded in northern China were caused by the regional semiarid-arid paleoclimate in the late Early Cretaceous, which was related to ocean anoxic event 1 (OAE 1) under the global hothouse climate.