Depositional environment of shales and enrichment of organic matters of the Lower Cambrian Niutitang Formation in the Upper Yangtze Region

Natural Gas Industry B

Liang He¹  Qiuzi Wu¹  Jinchuan Zhang²  Yue Lei³  Liqing Chen⁴  Shijing Chen⁵  Kesu Zhong⁶  Dingyuan Li⁶  Xue Yang⁷ 

[1] Beijing, 100083, China;Corresponding author. No. 83, 1st Section of Jianshe North Road, Chenghua District, Chengdu City, 610051, Sichuan Province, China.;Gasfield Company, Chengdu, Sichuan, 610051, China;Gasfield Company, Mianyang, Sichuan, 621700, China;;Northwest Sichuan Gas Deposit of Petro China Southwest Oil &School of Energy Resources, China University of Geosciences (Beijing);;Shale Gas Research Institute, Petro China Southwest Oil &

关键词: Shale;    Depositional environment;    Organic matter enrichment;    Niutitang Formation;    Lower Cambrian;    Upper Yangtze Region;   

DOI  :  

来源: DOAJ

【 摘 要 】

The Niutitang Formation in the Upper Yangtze Region comprises a set of the Early Cambrian black shales containing abundant organic matter. We investigated the relationship between the depositional environment and organic matter enrichment based on core description, slice observation, and geochemical analysis of the main trace elements. Additionally, we reconstructed the depositional environment of the Lower Cambrian Niutitang Formation shales and analyzed the main factors controlling the organic matter enrichment of shales during different deposition periods. According to the division of lithofacies, seven types of lithofacies have been identified in the Niutitang Formation. It is believed that the Niutitang Formation in northern Guizhou comprises a set of silicon-rich shales deposited on the continental shelf slope and formed under the control of different hydrodynamic forces. The main factors controlling its formation mechanism changed many times, from the initial hydrothermal deposition and enrichment controlled by oxygen deficiency to the enrichment accelerated by the high productivity at the surface of the water body. Subsequently, the change in sea level caused the change in the sea depth, which made it difficult for lower productivity to promote organic matter enrichment. Multiple main factors cooperated with the evolution of the depositional environment and jointly controlled the formation and distribution of organic-rich shales.

【 授权许可】

Unknown