摘要
本文介绍的是在青藏高原北部进行爆破地震研究的某些结果。爆破地震剖面位于青海省南部沱沱河至格尔木,测线长340km。研究结果表明:沱沱河和楚玛尔地区莫氏界面深度为55km。格尔木地区为47km。下地壳包含一层厚为8km,其层速度为7.2km/s,可能富含玄武岩物质的层。约基台湖—金沙江深大断裂和昆仑南缘板块结合带是延伸到上地幔顶部的岩石圈断裂。其中昆仑南缘板块结合带倾向北,北盘抬升达8km。它表明两个微板块碰撞过程中,柴达木微板块仰冲,而巴颜喀拉微板块俯冲。
Deep-crustal structures in the Tuotuo River-Golmud region in the northern part of the Qinghai-Xizang plateau were investigated by explosion seismology,This paper presents some results of the study.Results indicate that the sedimentary strata in this region become thicker and thicker from north to south.The sediments are 2-3 km thick in the Golmud arca and 4-5 km thick in the Qumar and Tuotuo River areas,with a velocity of 5.2-5.6 km/s.The crust consists of five layers.In the lower crust.there might be a layer censisting dominantly of basalt and its analogues,with a velocity of 7.2 km/s and a thickness of 8 km.The layer is not present in the Xizang plateau.It may show that there are differences in substances on two sides of the Bangong Co-Nujiang great fracture.The Moho here is 48 km deep in the Golmud area and 55 km deep in the Tuotuo River and Qumar areas.The Yujitai Co-Jinshajiang great fracture and the great fractures on the southern edge of Korum are fractures extending into the lithosphere atop the upper mantle.The great fracture on the southern edge of Korum dips to the north,the hanging wall moving up for 8 km.It may indicate that the Qaidam microplate thrust over and the Bayan Har microplate thrust down when they came into collision.
作者
卢德源
陈纪平
Lu Deyuan;Chen Jiping(562 Geological Research Party,MGMR,Sanhe,Hebei)
出处
《地质论评》
1987年第2期122-128,共7页
Geological Review
