青海都兰地区前泥盆纪古陆块的物质组成和重大地质事件

The constitution and importance geological events of Pre-Devonian in the Dulan, Qinghai

通过对青海都兰地区前泥盆纪地块的地质、地球化学和同位素年代学研究,将其由北向南划分为欧龙布鲁克微陆块、沙柳河超高压碰撞带和柴达木陆块三个构造单元。基本查明了欧龙布鲁克古陆块主要由德令哈片麻岩、莫河片麻岩、达肯大坂岩群、万洞沟群和全吉群组成,柴达木盆地北缘高压碰撞带主要为中新元古代沙柳河岩群、花岗闪长质片麻岩、英云闪长质片麻岩、钾长花岗片麻岩、榴辉岩、滩间山群和蛇绿岩,柴达木古陆块主要由古元古代金水口岩群和夕线堇青花岗片麻岩组成。详细厘定了本区前泥盆纪重要地质事件,特别是与Rodinia超大陆有关的汇聚与裂解事件。同时,利用先进的同位素地质年代学手段,确定了本区重要地质事件的地质时代和序列,为研究我国中-新元古代古陆块汇聚与裂解关系,以及它们在整个超大陆中的位置提供了证据。

Research on geology, geochemistry and geochronology of the old, Pre-Devonian continent in the Dulan area, Qinghai indicates that the continent can be divided into three tectonic units, namely, the Olongbuluck old continent block, the Shaliuhe UHP collision belt and the Caidam continent block. The Olongbuluck old continent block consists mainly of the Delingha Gneiss, Mohe gneiss, Dakandaban Group, Wandonggou Group and Quanji Group. The Shaliuhe UHP collision belt is composed mainly of the Shaliuhe Group, granodiorite gneiss, tonalite gneisss, moyite gneiss, eclogite, Tanjianshan Group and ophiolite. The Caidam old continent block is made up of the paleo-Proterozoic Jinshuikou Group and sill-cord-granitic gneiss. Some important geological events in Pre-Devonian, especially those related to the assembly and break-up of the Rodinia supercontinent have been defined in detail. Meanwhile, the geological age of these important events and sequence had been confirmed by advanced isotopic geochronology method. These events have provided evidences for studying the relation and location of Rodinia assembly and its break-up in Meso- and Neo- Proterozoic in China and for international correlation.