Paleo-Environment Reconstruction of the Middle Permian Lucaogou Formation,Southeastern Junggar Basin,NW China:Implications for the Mechanism of Organic Matter Enrichment in Ancient Lake  

作　　者：Dawei Cheng Chuanmin Zhou Zhijie Zhang Xuanjun Yuan Yinhe Liu Xingyu Chen 

机构地区：[1]Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China [2]School of Earth and Space Sciences,Peking University,Beijing 100871,China

出　　处：《Journal of Earth Science》2022年第4期963-976,共14页地球科学学刊（英文版）

基　　金：financially supported by the Petro China Science and Technology Major Project(Nos.2016B-0302 and 2019B-0302)。

摘　　要：The Middle Permian Lucaogou Formation is the source rock and the main oil shale producing formation in the southeastern Junggar Basin.This study focused on the Lucaogou Formation exposed in two outcrop sections on the northern flank of the Bogda Mountain,namely the Jingjingzigou and Dalongkou sections.Here,we present integrated analysis of the sedimentology,major and trace elements,mineral components and total organic carbon contents.The paleo-environment was reconstructed including provenance,redox conditions,paleo-salinity,chemical weathering intensity and primary organic matter productivity.The results showed that the upper and lower units were deposited in distinct depositional environments with different organic matter accumulation mechanisms.The lower unit was characterized by low lake level,dry climate,fresh-brackish and well-oxygenated water.While during the deposition of the upper unit the lake level rose,climate turned wetter and the bottom water became less oxidized and much saltier.The mechanism of the organic matter accumulation is different for these two units.The preserved organic matters were mainly controlled by the primary productivity in the lower unit and by the redox conditions in the upper unit.

关 键 词：trace element redox condition PALEOSALINITY primary productivity chemical weathering 

分 类 号：P618.13[天文地球—矿床学]