西藏昌果晚三叠世-早侏罗世深水重力流沉积的发现及意义  

Discovery and significance of deep water gravity flow deposits from late Triassic to early Jurassic in Changguo area, Tibet, China

作　　者：李楠 杨文光[1] 朱利东[1] 解龙 钟摇 麦源君 周豫 张洪亮 LI Nan;YANG Wenguang;ZHU Lidong;XIE Long;ZHONG Yao;MAI Yuanjun;ZHOU Yu;ZHANG Hongliang(State Key Laboratory of Oil&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）》2022年第6期653-664,共12页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(41972118);中国地质调查局项目(DD20160015)。

摘　　要：通过野外地质调查,结合室内薄片鉴定、粒度分析和砂岩碎屑组分分析,探讨冈底斯南缘上三叠统-下侏罗统刘琼组深水重力流沉积类型、垂向序列、成因机制和深水沉积模式。刘琼组以碎屑岩和火山岩组合为特征,碎屑岩中发育正递变层理、平行层理、沙纹层理、包卷层理、块状层理和火焰状构造等沉积构造,具有典型重力流沉积特征,并可进一步识别出滑塌沉积、砂质碎屑流沉积和浊流沉积三种重力流沉积类型。砾岩和砂岩岩相学以及砂岩碎屑组分统计结果显示刘琼组物源来自北侧同期火山弧。综合区域地质调查研究成果,认为刘琼组具有弧前盆地沉积特征,为雅鲁藏布江洋向北俯冲、向南增生过程的沉积记录。Based on the field geological survey, combined with laboratory thin section identification, grain size analysis and sandstone detrital composition analysis, the sedimentary types, vertical sequences, genetic mechanism and deep-water sedimentary models of Upper Triassic-Lower Jurassic Liuqiong Formation in the southern Gangdise margin are discussed. The study shows that Liuqiong Formation consists of a set of clastic rock and volcanic rock combination. Graded bedding, parallel bedding, sand grain bedding, lapped bedding, massive bedding and flame structure developed in the Liuqiong Formation clastic rocks are indicative of typical gravity flow deposits, and three gravity flow sedimentary types, namely slump deposit, sandy clastic flow deposit and turbidity current deposit have been recognized. The lithography of conglomerate and sandstone and the statistics of sandstone detrital composition show that the provenance of the Liuqiong Formation is from the northern volcanic arc. Based on the research results of regional geological survey, the Liuqiong Formation has the characteristics of forearc basin, which is the sedimentary record of the northward subduction and southward accretion process of the Yarlung Zangbo Ocean.

关 键 词：深水重力流 刘琼组 弧前盆地 西藏 

分 类 号：P512.32[天文地球—地质学]