Environmental Effects on Differential Organic Matter Enrichment of the Lower Cambrian Shale,Tarim Basin,NW China  

作　　者：ZHAO Yawen WU Guanghui YI Yan CHEN Yongquan WU Yonghong JING Bing WANG Jian 

机构地区：[1]School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China [2]PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China [3]Qiangtang Basin Research Institute,Southwest Petroleum University,Chengdu 610500,China [4]Southwest Petroleum University,PetroChina Key Laboratory of Carbonate Reservoir,CNPC,Chengdu 610500,China [5]PetroChina Southwest Oil&Gasfield Company,Chengdu 610051,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第5期1523-1537,共15页地质学报（英文版）

基　　金：partly supported by the National Natural Science Foundation of China(Grant No.42241206,91955204);the Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.4224100017,2020CX010101)。

摘　　要：Early Cambrian shale is an important petroleum source rock around the world.Because of little drilling data and poor seismic data,until recently,organic matter enrichment of the Lower Cambrian Yuertusi and Xishanbulake formations shale is still an enigma in the Tarim Basin,northwestern China.Total organic carbon(TOC),major and trace element data of Cambrian shale samples from five boreholes have been analyzed to decipher the mechanism of the organic matter enrichment.The results show that the shales deposited in the western restricted intraplatform have much higher TOC contents(3.2%-19.8%,on average 11.0%)than those from the eastern basin(2.2%-10.2%,on average 4.5%).The paleoproductivity proxies(Ba,Ba/Al,P/Al)in the western restricted platform are much higher than those in the eastern basin.The trace element indicators such as V/Cr,Ni/Co,Mo-TOC and Mo_(EF)-U_(EF)suggest an anoxic environment across the basin,but a more restricted environment in the western intraplatform.The paleoproductivity rather than anoxic condition and hydrothermal activity are concluded to have resulted in the differentiation of the organic matter enrichment from the western intraplatform to eastern basin in the early Cambrian shales;the restricted environment was favorable for paleoproductivity and preservation of organic matter.

关 键 词：SHALE organic matter enrichment PALEOPRODUCTIVITY restricted environment CAMBRIAN Tarim Basin 

分 类 号：P618.13[天文地球—矿床学]