西藏萨嘎地区构造岩石地层新认识及其构造意义  

NEW IDEAS OF TECTONOSTRATIGRAPHY AND ITS TECTONIC SIGNIFICANCE IN SAGA REGION,SOUTHREN TIBET

作　　者：李亚林[1] 王成善[1] 胡修棉[2] M Bak 王立成[1] 王进军[4] 陈蕾[2] 

机构地区：[1]中国地质大学青藏高原地质研究中心,北京100083 [2]南京大学地球科学系,江苏南京210093 [3]Institute of Geological Sciences,Jagiellonian University [4]成都地质矿产研究所,四川成都610082

出　　处：《矿物岩石》2007年第3期55-62,共8页Mineralogy and Petrology

基　　金：国家自然科学基金(40672086);国土资源部"青藏高原油气资源战略选区调查与评价"项目

摘　　要：对萨嘎地区古近纪海相沉积放射虫化石和上覆陆相沉积年代学研究证实,原古近系折巴群包含了早白垩世—早始新世不同时代的沉积,而不整合在其上陆相磨拉石沉积时代为早始新世中晚期(41.2 Ma^46.2 Ma)。变形分析表明萨嘎地区原古近系折巴群经历了强烈复杂的构造变形,不同时代的沉积岩系呈构造岩片在空间上重复叠置,表现出典型构造岩石地层单元的特点。萨嘎地区海相沉积岩系中始新世早期放射虫化石的发现和构造属性的确定,表明始新世早期沿萨嘎一线存在一定规模的特提斯海盆,特提斯洋的最终关闭和印度-欧亚板块全面碰撞造山作用发生于早始新世中晚期,并在此后发育与碰撞造山作用相关的磨拉石沉积。The stratigraphic age, division and tectonic attributes in Saga area, Southern Tibet provide much evidence on the evolution of Tethys and Indo-Asian collision. By the radiolarians research on the Paleogene Zheba Group in Saga region,it can be recognized that this marine stratum is comprised of Early Cretaceous-Early Eocene deposits and the molassic deposits lay over the marine sediments are 41.2 Ma- 46. 2 Ma. Structure analysis reveals that Zheba Group have undergone strong deformation and formed different tectonic slices with differnent age. These tectonic slices distributed disorderly and show the characteristics of tectono-stratigraphic units. The discovery and documentation of Early Eocene radiolarian assemblages in Saga area indicate that there was a deep sea in Saga area during early Eocene and the Indo and Asian continents collision took place during middle-late stage of early Eocene, followed by the formation of molasse after collision.

关 键 词：雅鲁藏布江缝合带 地层时代 构造岩石地层 放射虫 磨拉石 

分 类 号：P542[天文地球—构造地质学]