Maokouan and Upper Permian sedimentary facies in the Jiangsu-Zhejiang-Anhui region

The Maokouan and Permian formations in the Jiangsu-Zhejiang-Anhui region are mostly diachronous. During the Maokouan stage,a vast expanse of Qixian carbonate platforms disappeared,instead the deltas,shallow seas and carbonate platforms were well defined. The debris were mainly derived from the Cathaysian and East Shandong ancient land,and the clear-water benthic organisms were widespread throughout the study area. The distribution of the Lengwu sponge knoll reef microfacies has also discolsed the palaeogeographic features in this area. The variations in biofacies and lithofacies in the Gufeng Formation have reflected the palaeogeographic differences during he early Maokouan. the terrigenous clastics apparently decreased in the Late Permian. There existed two facies belts,i, e. the carbonate platform and continental shelf facies belts,and the boundary between them may be exact position of the Jiangnan fault.