西藏色哇地区中新生代构造演化史讨论  

Discussion on the Meso-Cenozoic tectonic evolution history in Sewa area,Tibet

作　　者：肖永春[1] 马超[1] 于琪 刘振宇[1] XIAO Yong-chun;MA Chao;YU Qi;LIU Zhen-yu(Institute of Geological Survey of Jilin Province,Changchun 130102,Jilin,China)

机构地区：[1]吉林省地质调查院,吉林长春130102

出　　处：《吉林地质》2020年第4期51-59,共9页Jilin Geology

摘　　要：通过对西藏北部双湖县色哇地区的班公湖—怒江断裂带构造特征分析,以及断裂带两侧班公湖—怒江结合带与羌塘陆块中新生代地层沉积构造环境重塑,讨论了色哇地区中新生代构造演化史。研究表明,色哇地区羌塘陆块中生代地层主要有上三叠统日干配错组,下侏罗统曲色组,中侏罗统色哇组、莎巧木组,分别为中薄层粉晶灰岩建造-薄层泥晶灰岩夹粉砂岩建造-泥岩夹粉砂岩建造-粉砂岩夹石英砂岩建造,反映了广海浅海碳酸盐台地相—浅滨碳酸盐岩台地相—较深水泥质浅海陆棚相—浅海陆棚相沉积构造环境。班公湖—怒江结合带中生代地层主要有上侏罗统吐卡日组、沙木罗组,下白垩统去申拉组,分别为中薄层粉晶灰岩夹少量石英砂岩建造-中薄层长石石英砂岩夹少量灰岩建造-陆相紫红色碎屑岩沉积为主夹陆相裂隙式喷发的中酸性火山岩,反映了浅海碳酸盐相—滨浅海相—山前盆地相(磨拉石建造+同碰撞陆相火山岩)沉积构造环境。新生界新近系康托组、第四系其不整合覆盖于全区各中生代地层单元之上,反映了隆升山间断陷盆地干燥炎热的陆相沉积构造环境。班公湖—怒江断裂带在本区表现为一向北倾斜、多期次活动的逆冲断层,其上盘发育宽约100~500 m强片理化带。结合区域资料认为,色哇地区中新生代经历了班公湖—怒江洋拉开(T3—J2)、挤压汇聚(J3—K1)、碰撞造山(K1—K2)、高原隆升(N—Q4)构造演化阶段。Based on the analysis of the tectonic characteristics of the Banggonghu-Nujiang fault zone in Sewa area,Shuanghu County,northern Tibet,and the remolding of the meso-Cenozoic sedimentary and tectonic environments of the Banggonghu-Nujiang joint zone and the Qiangtang block on both sides of the fault zone,the tectonic evolution history of the Meso-Cenozoic in Sewa area is discussed.The results show that the Meso-Cenozoic strata in the Qiangtang block in the Sewa area mainly consist of the Upper Triassic Riganpeicuo Formation,Lower Jurassic Quse Formation,Middle Jurassic Sewa Formation and Shaqiaomu Formation.They are medium thin layer silty limestone construction-thin layer micrite sandwich siltstone construction-mudstone sandwich siltstone construction-siltstone sandwich quartz sandstone construction respectively,reflecting the sedimentary and tectonic environment of the neritic carbonate facies,littoral and neritic facies and piedmont basin facies(molasse formation+syncollisional continental volcanic rock).The Mesozoic strata in Bangonghu-Nujiang junction zone mainly include the Upper Jurassic Tukari Formation and Shamuluo Formation,and the Lower Cretaceous Qushenla Formation,which are respectively composed of medium thin layer of silty limestone with a small amount of quartz sandstone formation,medium thin layer of feldspathic quartz sandstone with a small amount of limestone formation,Continental purplish red clastic rock sedimentation,intercalated with Continental fissure eruption intermediate acid volcanic rock,reflecting shallow sea carbonate facies and shore shallow Marine Piedmont basin facies(Molasse formation+syn collision continental volcanic rocks)sedimentary tectonic environment.The Neogene Cangtuo Formation and Quaternary unconformity cover all Mesozoic stratigraphic units in the whole region,reflecting the dry and hot continental sedimentary tectonic environment of the uplifted mountain discontinuous basin.The Bangonghu-Nujiang fault zone in this area is a north-dipping thrust fault with multiple pe

关 键 词：色哇地区 班公湖—怒江结合带 羌塘陆块 沉积构造环境 

分 类 号：P542[天文地球—构造地质学]