Tectonic paleogeography of Late Sinian and its significances for petroleum exploration in the middle-upper Yangtze region, South China

WANG Zecheng,JIANG Hua,CHEN Zhiyong,LIU Jingjiang,MA Kui,LI Wenzheng,XIE Wuren,JIANG Qingchun,ZHAI Xiufen,SHI Shuyuan,LI Qi

Fig. 5. Typical petrological characteristics of the Dengying Formation in the middle and upper Yangtze region. (A) Evaporative lagoon, dolomite containing gypsum clumps (Well Wei 117, Deng 1 Member); (b) restricted platform, barite-bearing micritic dolomite (Huize Yinchangpo section, Deng 2 Member); (c ) Restricted platform, siliceous band dolomite (E’bian Xianfeng section, Deng 4 Member); (d) Platform margin, dolarenite (Well Moxi 108, Deng 4 Member); (e) Intra-platform dolomite with algal layers (Xianfeng section of E’bian, Deng 2 Member); (f) micritic dolomite at platform margin (Gaoshi 102, Deng 4 Member); (g) dolarenite inside platform (Well Zitan 1, Deng 2 Member); (h) thin micritic dolomite in platform sag (Yangjiaping section of Shimen, Deng 1 Member); (i) restricted platform, dolomite with algal laminae (Well Moxi 108, Deng 2 Member); (j) platform margin slope, dolomite and layered siliceous dolomite (Zhenba Laoqihe section, Deng 4 Member).