Distribution and ages of Cambrian and Ordovician marine red beds in the northern margin of Qiadam Basin, Qinghai Province

According to the field investigation in the northern margin of the Qiadam Basin, Qinghai Province, and previous results, the study discussed the Cambrian and Ordovician marine red beds in this area. Nineteen marine red beds have been recognized in the Cambrian and Ordovician strata in the northern margin of the Qiadam Basin. Among them twelve are Cambrian marine red beds and seven Ordovician marine red beds. Most of them belong to the Shelf Red Beds (SRBs), only four of them are of the Oceanic Red Beds (ORBs) (Shihuigou Formation marine Red Beds of Ordovician). Based on the fossils in marine red beds and the upper and lower layers of the red beds, this paper preliminarily discussed the general ages of the red beds and compared them with the coeval marine red beds in the main blocks of China. This results in this study provide basic data for further research in the distribution pattern and stratigraphic correlation of the Cambrian and Ordovician marine red beds in China and even the world. In addition, the distribution of the Cambrian marine red beds in Tangshan, Hebei Province, and the widespread events of Dapingian to early Darriwilian (Middle Ordovician) marine red beds in South China are discussed. © 2019, Science Press. All right reserved.