柴西北缘鄂博梁地区下干柴沟组泥岩地球化学特征及古环境  

Geochemical characteristics and paleoenvironmental significance of the Paleogene Xiaganchaigou Formation mudstone in the Eboliang area,northwest margin of Qaidam Basin,China

作　　者：任栩莹 李凤杰[1] 张鹏飞 REN Xuying;LI Fengjie;ZHANG Pengfei(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059

出　　处：《成都理工大学学报（自然科学版）》2023年第2期172-186,共15页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家重点研发计划项目(2018YFC0604201)。

摘　　要：以柴达木盆地西北缘鄂博梁地区为例,通过痕量元素及稀土元素分析测试,结合沉积综合柱状图,探讨古近系下干柴沟组的古盐度、古气候和古氧化-还原条件等变化特征。样品具有明显的Eu负异常及轻微的Ce负异常,氧化-还原指标Ni/Co、V/Cr、U/Th一致指示氧化条件,古气候指标Sr/Cu值与Sr、Rb/Sr值指示的气候温湿变化趋势一致,古气候条件与Sr/Ba、Th/U判断出的古盐度变化相符合。古近纪青藏高原隆升高度较低且范围有限,鄂博梁地区下干柴沟组沉积期处在温暖湿润的淡水环境。Through the analysis of trace element,rare earth element and comprehensive sedimentary histogram,the characteristics of paleo-salinity,paleo-climate and paleo-oxidation and reduction conditions of the Eocene Xiaganchaigou Formation in Eboliang area of the northwestern Qaidam Basin are discussed.The results show that the samples from the Xiaganchaigou Formation have obvious negative Eu anomaly and slight negative Ce anomaly.The oxidation-reduction indices Ni/Co,V/Cr and U/Th all indicate oxidation conditions.The paleo-climate indices Sr/Cu are consistent with the climatic temperature and humidity trends indicated by Sr and Rb/Sr and the paleo-climate conditions are consistent with the paleo-climate changes determined by Sr/Ba and Th/U.Above geochemical analysis of Xiaganchaigou Formation indicates that the uplift height of the Qinghai-Tibet Plateau in Paleogene was low with limited affected range and the warm and wet air of the ancient Indian Ocean could bring precipitation to the Qaidam Basin,making the deposition of whole Xiaganchaigou Formation in Eboliang area in a warm and humid climate.

关 键 词：柴达木盆地 鄂博梁 古近系 元素地球化学 古环境 古气候 

分 类 号：P595[天文地球—地球化学] P532[天文地球—地质学]