分层滑脱:羌塘盆地构造研究的新概念  

Stratified detachment deformation: New concept for studies on the tectonics of Qiangtang Basin

作　　者：何登发[1] 王成善[1] 管树巍[2] 李传新[1] 王瑜[1] 开百泽 梅庆华 贺鸿冰 He Dengfa;Wang Chengshan;Guan Shuwei;Li Chuanxin;Wang Yu;Kai Baize;Mei Qinghua;He Hongbing(China University of Geosciences(Beijing),Beijing 100083;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083;Sinopec Exploration Company,Chengdu 610041)

机构地区：[1]中国地质大学(北京),北京100083 [2]中国石油勘探开发研究院,北京100083 [3]中国石油化工股份有限公司勘探分公司,成都610041

出　　处：《地质科学》2023年第1期1-17,共17页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金企业创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究”(编号:U19B6003-01)资助。

摘　　要：羌塘盆地地处青藏高原腹地,油气资源丰富,是我国目前唯一未大规模勘探的含油气盆地。研究其地质结构,将为青藏高原科学考察与油气地质条件评价奠立重要基础。本文针对羌塘盆地“古生代南、北基底有别,中生代周缘板块构造边界限制,新生代陆内构造变形强烈”这一典型的缝合带上的多旋回复合、叠合盆地,利用盆地内部的钻井与高精度反射地震剖面对其分层地质结构进行研究。结果表明,羌塘盆地发育上三叠统肖茶卡组,中-下侏罗统雀莫错组,中侏罗统布曲组与中侏罗统夏里组泥岩、膏岩、膏泥岩等4套区域性滑脱层;此外,还发育下侏罗统曲色组泥质岩,上侏罗统索瓦组的泥灰岩、泥岩,始新统唢呐湖组的膏盐、泥岩,二叠系煤层等4套局部性滑脱层;基底内部发育韧性剪切层。它们在垂向上将羌塘盆地分划为软弱层与能干层相间的多套组合。受区域性滑脱层控制,羌塘盆地发育分层变形系统;滑脱层上、下构造几何学样式差异较大,运动学指向也不一致;整体表现为大型多重滑脱构造变形系统。分层滑脱变形系统约束了油气保存单元的分布。分层滑脱变形将为进一步认识羌塘盆地,评价羌塘盆地的油气保存单元提供新的学术思路。The Qiangtang Basin with abundant oil and gas resource is located in the interior of the Qinghai-Tibet Plateau, which is the only basin with low-hydrocarbon-prospecting-degree in China. To study its geological structure can set up a basis for the science exploitation and the appraisals of the oil and gas geological conditions in the plateau. The Qiangtang Basin is a classical multi-cycle composite and superimposed basin developed right upon the suture zone,which is characterized by the Paleozoic basement differentiated in the northern and the southern parts, the Mesozoic marine basin controlled by the peripheral plate tectonic boundaries, and the Cenozoic intra-continental extensive deformation. The paper takes use of the borehole data and the latest high-resolution seismic reflection profiles to study the stratified geologic framework of the basin. It shows that the basin develops the mudstones, the gypsum rocks, and the gypsum-muddy stones of the Upper Triassic Xiaochaka Formation, the Lower and Middle Jurassic Quemoco Formation, the Middle Jurassic Buqu Formation, and the Middle Jurassic Xiali Formation as the four series of regional detachment layers, as well as the four local detachment intervals such as the Lower Jurassic argillaceous rocks, the Upper Jurassic Suowa Formation marls and mudstones, the Eocene Suonahu Formation gypsum and mudstones, and the Permian coal beds. The ductile zones are occurred in the basement. These detachment zones subdivide vertically the basin into multi-series of assemblages of soft rock intervals and the strong rock intervals. Controlled by the regional detachment layers, the Qiangtang Basin developed the stratified deformation tectonic system. The geometric structural styles and the kinematic vergences are quite different from above and below the detachment zones. The basin is characterized by the large-scale multi-detachment tectonic deformation systems. The stratified detachment deformation system controls the distribution of the oil and gas preserving units. The concept o

关 键 词：滑脱层 分层变形 地质结构 油气保存单元 羌塘盆地 

分 类 号：P542[天文地球—构造地质学]