东昆仑西段晚古生代盆地系  

The Late Paleozoic Basin System in the Western Part of East Kunlun

作　　者：尹福光[1] 潘桂棠[1] 

机构地区：[1]成都地质矿产研究所,四川成都610081

出　　处：《地球学报》2008年第1期31-38,共8页Acta Geoscientica Sinica

基　　金：川渝滇黔综合地质研究项目(编号:1212010310201)资助

摘　　要：东昆仑西段晚古生代从北向南分别为昆北弧后盆地、昆中岛弧及昆南弧前增生楔。在二叠纪,增生楔又转变成岛弧及弧后盆地。昆北弧后盆地石炭纪发育有陆缘到深海盆地的沉积,二叠纪由碎屑岩过渡为浅海碳酸盐岩。昆中岛弧带沉积盖层为一些碳酸盐岩孤立台地和小的山间盆地,并有火山熔岩、火山碎屑岩的堆积。昆南弧前盆地岩石类型非常复杂,石炭纪包括了陆源碎屑岩、火山熔岩、火岩碎屑岩、钙屑浊积岩、硅质岩等。二叠纪的弧间盆地从深海盆地演化为浅海碳酸盐岩沉积。前锋弧也逐渐露出水面,形成孤立灰岩台地。东昆仑西段晚古生代沉积整体特征具有沉积相分布不对称性及"盆岭"相间展布、沉积类型多样性、物源、古流向的双(多)向性、沉积序列的两层性、沉积物的成熟度低、近源等。盆地演化可划分为盆地扩张阶段、弧陆碰撞阶段两个阶段。总体表现为弧后盆地性质的沉积与演化特点。The western part of the East Kunlun orogenic belt can be divided into three belts, namely, the back-arc basin, the arc belt and the accretion wedge. In the back-arc basin, there are sediments varying from continental shelf to deep basin, and intermediate-acidic volcanic deposits as well as limestone and sandstone. In Late Permian, deposition ended and changed into land. The sedimentary cover of the arc belt is a number of isolated carbonate platforms and intramontane basins. There existed intense volcanic activities, resulting in the formation of such facies of volcanic rocks as subvolcanic facies and explosive facies. The accretion wedge of East Kunlun is very complex in composition. Large quantities of inter-mediate acidic volcanics were carried into the basin and formed such rocks as continental detritus turbidite, calcium detritus turbidite and silicalite. In Late Paleozoic, the deposition in the western part of East Kunlun was characterized by the asymmetry of sedimentary facies, the alternate distribution of “basin and range”, the diversity of sedimentary types, the double or multiple directions of provenance and paleocurrent, the two-layer feature of the sedimentary sequence, and the low maturity of sediments as well as close provenance. The evolution of the western part of East Kulun in Late Paleozoic can be divided into basin expansion stage and arc-continent collision stage. Hence in Late Paleozoic the western part of East Kunlun was a arc-basin system.

关 键 词：东昆仑西段 晚古生代 盆地系 

分 类 号：P534.4[天文地球—古生物学与地层学]