Tectonic sequence stratigraphy and sedimentary environment evolution ofprototype basin in middle and upper Yangtze Region

In order to promote the exploration and development of shale gas in southern of China,the geological theory of sequence stratigraphy,sedimentary environment and so on was carried out. Through field geological survey,drilling geology research and reference to previous geological data,comprehensive stratigraphy was compared in Sichuan Basin,eastern Chongqing and western Hunan-Hubei,and tectonic sequence stratigraphy was divided and the sedimentary environment of prototype basin of middle and upper Yangtze region was restored in important geological period.The results showed that three tectonic sequences had been divided in the middle and upper Yangtze Region since Sinian. It was the first structural sequence from Sinian to Silurian Period,which formed a complete Wilson Cycle. It was the second structural sequence from Devonian to Triassic,which formed a complete Wilson Cycle. It was the third structural sequence from Jurassic to Neogene,which formed a complete Wilson Cycle. The three tectonic sequences reflected the tectonic evolution history of entire Yangtze Plate. The main controlling factors of tectonic sequence was the expansion and closed movement of oceanic basin between plates and the sedimentary environment of each stage of tectonic sequence depended on the basin’s distance from the master ocean.