新疆地学断面深地震反射剖面揭示的西昆仑-塔里木结合带岩石圈细结构  

Detail Lithospheric Structure of the Contact Zone of West Kunlun and Tarim Evealed by Deep Seismic Reflection Profile along the Xinjiang Geotransect

作　　者：高锐[1] 肖序常[1] 刘训[1] 管烨[1] 李秋生[1] 卢德源[1] 李朋武[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《地球学报》2001年第6期547-552,共6页Acta Geoscientica Sinica

基　　金：原地质矿产部 ( 95 0 12 0 4);国家新疆 30 5项目 ( 96 915 0 7 0 3);国家自然科学基金 (F49734 2 30 );国家重点基础研究发展规划项目(G19980 40 80 0 )的联合资助

摘　　要：横过西昆仑 塔里木结合地带的深地震反射剖面 ,首次揭露出新疆地学断面南部山盆结合部位地壳与上地幔顶部的精细结构 ,发现了塔里木岩石圈下部南倾、西昆仑山岩石圈下部北倾的强反射特征 ,它们相向倾斜、相互交织 ,构成了塔里木岩石圈挤入到西昆仑北带之下 ,与青藏高原西北缘岩石圈相碰撞的地震证据。深地震反射剖面还揭示出西昆仑山与塔里木盆地在岩石圈尺度呈“V”型的盆山耦合关系 ,这种“V”型的耦合关系代表了陆内陆A near vertical deep seismic reflection profile across the contact zone of West Kunlun and Tarim completed in 1998. The seismic line began the front of the southern Tarim basin extended southward into West Kunlun Mountains, total about 100 km long. Totaling 432 channels of recording equipment were deployed, the sensors were 10 Hz geophones with an average spacing of 50 m, all recorded to 30 s with a 600 channel SN 388. Some 183 shots (charge size 48～200 kg), with an average spacing of 500 m, were used as sources of seismic energy along the seismic line. Seismic data are giving first view of crustal structure of the area.Conventional CDP processing resulting in a stacked time section shows a very detailed structure with different reflectors down to 30 s two way time (TWT). The Moho is clearly observed on the CDP profile from north to south, where it occurs at a depth of 57～60 km (18～19 s) underlying the West Kunlun. The most prominent feature of the seismic profile in the northern West Kunlun Mountains is a gently north dipping band of reflections extending from 8～21 s, while reflectors in southern Tarim basin show dip to south. The stronger reflections which are north dipping under the west Kunlun Mts. and south dipping under the southern margin of the Tarim basin, constitute the evidence of the Tarim lithosphere collided with the lithosphere of the northwestern Tibetan plateau beneath the edge of the west Kunlun Mts.. The Image of reflection structure reveals out that the V shaped basin and range coupling relationship between west Kunlun Mts. and Tarim basin in the lithosphere scale. This pattern may be an expression of the intra-continental collision process.

关 键 词：青藏高原 西昆仑 塔里木 深地震反射 陆-陆碰撞 盆山耦合 岩石圈 细结构 新疆地学断面 

分 类 号：P31[天文地球—固体地球物理学]