青藏高原中东部古近纪盆地封闭的构造-沉积-岩浆活动和古气候响应  

The Closure of Paleogene Basins of East-Central Tibet in Response to Tectonic,Sedimentation,Magmatism and Paleoclimate

作　　者：周江羽[1] 王江海[2] B. K. HORTON An YIN M. S. SPURLIN 

机构地区：[1]中国地质大学(武汉)构造与油气资源教育部重点实验室,武汉430074 [2]中山大学海洋学院,广州510275 [3]Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas, Austin, TX 78712-0254, USA [4]Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095-1567, USA

出　　处：《地质学报》2011年第2期172-178,共7页Acta Geologica Sinica

基　　金：国家重点基础研究发展规划项目(编号G1998040800);国家自然科学基金项目(编号49972026,39972026);中国科学院重点项目(编号KZ952-J1-408);美国国家自然科学基金项目(Grant980612)联合资助成果

摘　　要：青藏高原中东部分布着一系列中小型古近纪盆地,详细的野外地质调查、盆地构造-沉积学和生物地层学、地球化学和岩浆岩的40Ar/39Ar年代学结果表明,盆内充填了紫红色的陆源碎屑岩夹火山碎屑岩、碳酸盐岩和石膏层,并被晚期岩浆岩所切割,盆缘地层发生大规模掀斜而形成高陡地层和挤压向斜,盆内地层发生褶皱变形。地层内部细碎屑岩孢粉和古植物、火山碎屑岩和侵入岩的40Ar/39Ar年代学揭示盆地充填沉积物形成于38～28Ma(晚始新世—早渐新世)。古近纪紫红色沉积物、碳酸盐岩和石膏层的出现代表干旱-炎热的古气候环境。印度-欧亚板块碰撞过程中因陆壳变形和高原早期构造隆升产生的走滑拉分和逆冲挤压是导致高原中东部古近纪盆地裂解和封闭的主要原因。In east-central Tibet,Many Paleogene elongate basins with medium-mini-type are distributed along the large-scale arc-shaped strike-slip and thrust belt of the Nangqian-Yushu and Batang-Lijiang.Detailed mapping,structural-sedimentologic,biostratigraphic,geochemical,and ^40Ar/^39Ar chronologic data from five Pleogene basins（Dongba,Shanglaxiu,Nangqian,Gongjue,and Mangkang）in the Nangqian-Yushu and Batang region of east-central Tibet indicate that the strata in basin margin developed a large-scale of tilting to form high-steep dip and extrusing syncline,fold and deformation,filled amaranth clastics interbeded with volcanoclastic rock,carbonite and gypsum in basins,and incised by late magmatite.Pollen and paleoflora in fine-clastic rock,^40Ar/^39Ar dating of volcanoclastic rock and magmatite show that the basin-filling sediments formed at 38-28 Ma（Late Eocene—Early Oligocene）.Paleogene amaranth sediments,carbonate and gypsum present a dry-fervent,evaporated paleoclimate environment.At the late Eocene to early Oligocene in Tibetan plateau（38～28 Ma）,the break and closure of Paleogene basins of east-central Tibet may foreshow the start of wide early tectonic uplift and crust deformation due to the Indo-Asia collision.

关 键 词：构造-沉积-岩浆活动响应 古近纪盆地 40Ar/39Ar年代学 青藏高原中东部 

分 类 号：P532[天文地球—古生物学与地层学]