祁连山新元古代中—晚期至早古生代火山作用与构造演化

发布时间：2018-04-18 23:07

本文选题：祁连山 + 俯冲和碰撞　；参考：《中国地质》2016年04期

【摘要】：祁连山地区的新元古代中—晚期至早古生代火山作用显示系统地时、空变化,其乃是祁连山构造演化的火山响应。随着祁连山构造演化从Rodinia超大陆裂谷化—裂解,经早古生代大洋打开、扩张、洋壳俯冲和弧后伸展,直至洋盆闭合、弧-陆碰撞和陆-陆碰撞,火山作用也逐渐从裂谷和大陆溢流玄武质喷发,经大洋中脊型、岛弧和弧后盆地火山活动,转变为碰撞后裂谷式喷发。850~604 Ma的大陆裂谷和大陆溢流熔岩主要分布于祁连和柴达木陆块。从大约550 Ma至446 Ma,在北祁连和南祁连洋-沟-弧-盆系中广泛发育大洋中脊型、岛弧和弧后盆地型熔岩。与此同时,在祁连陆块中部,发育约522~442 Ma的陆内裂谷火山作用。早古生代洋盆于奥陶纪末(约446 Ma)闭合。随后,从约445 Ma至约428 Ma,于祁连陆块北缘发育碰撞后火山活动。此种时-空变异对形成祁连山的深部地球动力学过程提供了重要约束。该过程包括:(1)地幔柱或超级地幔柱上涌,导致Rodinia超大陆发生裂谷化、裂解、早古生代大洋打开、扩张、俯冲,并伴随岛弧形成;(2)俯冲的大洋板片回转,致使弧后伸展,进而形成弧后盆地;(3)洋盆闭合、板片断离,继而发生软流圈上涌,诱发碰撞后火山活动。晚志留世至早泥盆世(420~400 Ma),先期俯冲的地壳物质折返,发生强烈的造山活动。400 Ma后,山体垮塌、岩石圈伸展,相应发生碰撞后花岗质侵入活动。
[Abstract]:The Mesoproterozoic to early Paleozoic volcanism in the Qilian Mountains shows a systematic temporal and spatial variation, which is the volcanic response of the Qilian Mountains tectonic evolution.With the tectonic evolution of the Qilian Mountains from the Rodinia supercontinental rift to pyrolysis, the early Paleozoic oceans opened and expanded, the oceanic crust subducted and extended behind the arcs, until the oceanic basin was closed, the arc-land collision and the land- continent collision.Volcanism also gradually erupts from the rift valley and continental overflow Black Tortoise, passing through the mid-ocean ridges, island arcs and back-arc basins.The continental rift and continental overflow lava transformed into post-collision rift eruption of .850 ~ 604 Ma are mainly distributed in Qilian and Qaidam landmasses.From about 550 Ma to 446 Ma, in the North Qilian and South Qilian ocean-trench-arc basin systems, the mid-ocean ridge type, island arc and back-arc basin type lava are widely developed.At the same time, in the central part of the Qilian block, an intracontinental rift valley volcanism of about 522 ~ 442 Ma was developed.The early Paleozoic ocean basin was closed at the end of Ordovician (about 446 Ma).Then, from about 445 Ma to about 428 Ma, postcollision volcanic activity developed in the northern margin of Qilian block.This time-space variation provides an important constraint on the deep geodynamic processes that formed the Qilian Mountains.This process includes: 1) upwelling of mantle plume or super mantle plume, resulting in rift and fragmentation of Rodinia supercontinent, opening, spreading, subduction of the early Paleozoic oceans, and the rotation of oceanic slabs accompanied by island arc formation, resulting in back-arc extension.Then the back-arc basin is formed, the oceanic basin is closed, the plate fragments are separated, and then the upwelling of the asthenosphere occurs, which induces post-collision volcanic activity.From the late Silurian to the early Devonian, the crust material exhumed from the early subduction stage, and after a strong orogenic activity of .400 Ma, the mountain collapsed, the lithosphere was extended, and the post-collision granitic intrusions occurred.
【作者单位】：中国地质调查局西安地质矿产研究所;
【基金】：中国地质调查局综合研究项目(121201120133,12120115070601,12120101100015004)资助~~
【分类号】：P317;P542

【相似文献】