柴达木东缘碰撞系统划分  

DIVISION OF SUBDUCTION-COLLISION SYSTEM IN THE EASTERN QAIDAM BASIN

作　　者：杨立功[1,2] 刘继顺[1,2] 于换涛[1,2] 刘文恒[1,2] 尹利君[1,2] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083

出　　处：《地质力学学报》2013年第1期72-81,共10页Journal of Geomechanics

基　　金：国家115科技支撑计划课题"柴达木南北缘铅锌矿成矿规律及大型资源基地评价技术示范研究"(编号:2006BAA01B06)

摘　　要：基于前人对于柴达木东南缘北北西向鄂拉山岩浆带的研究成果,结合研究区火山-岩浆岩、蛇绿岩和沉积地层的形成时代、环境、分布规律、构造发育以及热力学环境和重磁地球物理异常等因素,认为鄂拉山岩浆弧是松潘—甘孜板块以阿尼玛卿蛇绿岩带为缝合线向北俯冲的产物。在整个闭合过程中,深部发生了滑脱,浅部碰撞前为半岛+拗拉槽+洋岛+海槽的基本格局,构造运动经历了洋壳俯冲消减、陆内碰撞造山和地壳伸展3个阶段,区内花岗岩的起因,始于洋壳俯冲,发展于陆内碰撞,因而,所发育的岩浆岩具有I-S过渡型花岗岩的特征,是海西晚期—燕山早期构造运动的地质记录。通过演绎这一发展过程,划分了柴达木东南缘岩浆岩带的碰撞体系。Based on the research fruits of southeastern margin NNW trending on Ela Mountain magmatic belt, in Qaidam by predecessors, combing with the elements of formation age, environment, structure, thermodynamic, gravity and magnetic geophysical anomaly for volcano- magmatite, ophiolite and sedimentary strata, we consider that the Ela Mountain magmatic arc was the production taking Songpan-Ganzi plate with the suture of A＇nyemaqen Ophiolitic Belt as the northward closure. During the whole closing period, there was slippage in the in the bottom, and the shallow before colliding was the pattern of peninsulas ＋ Aulacogen ＋ oceanic. The tectonic movement experienced three stages of oceanic crust subduction reduction, intracontinental collision orogenesis and crust extension. The granite of research area started from oceanic crust subduction, developed in intracontinental collision, so it had dual character of I-S type granite, which is the geologic record of the tectonic movement in late Hercynian to early Yanshanian. With deducing the development process, the authors divided the collision system of magmatic belt in the southeastern margin of the Qaidam.

关 键 词：俯冲消减 碰撞造山 地壳伸展 半岛 拗拉槽 

分 类 号：P588.1[天文地球—岩石学]