内蒙古苏左旗南部华北板块北缘中新元古代-古生代裂解-汇聚事件的地质记录

Crack and assembly events of Meso-Neoproterozoic-Palaeozoic continental blocks in the sourthern area of Suzuoqi, Inner Mongolia.

内蒙古苏左旗南部温都尔庙群是不同时代、不同环境下的岩石组合经构造作用拼贴在一起的构造拼贴体。根据岩石组合、岩石地球化学和同位素年龄将其解体为古元古代宝音图群、中、新元古代温都尔庙群和早古生代蛇绿混杂堆积。宝音图群为陆缘拉张解体阶段源自结晶基底的裂解古陆块。中、新元古代温都尔庙群及赋存在早古生代蛇绿混杂堆积中的超镁铁岩、基性火山岩和硅质岩的洋壳组合代表中、新元古代 -早古生代陆缘拉张解体阶段的拉张过渡壳 ,早古生代末 -晚古生代初 ,本区构造体制由拉张转化为挤压 ,苏左旗南部出露的蛇绿混杂岩带以及大量的蚀变闪长岩、英云闪长岩、花岗闪长岩。

Ondor Sum Group is situated in the southern area of Suzuoqi, Inner Mongolia, which is divided into Baoyintu Group of Early Proterozoic era(1911Ma similar to 1708Ma), Ondor Sum Group of Meso-Neoproterozoic era(1511Ma similar to 826Ma), and ophiolitic melange of Early Paleozoic era based on rock association, nature of chemical petrology and isotopic age. Baoyintu Group is recognized as an ancient fragment from crystalline basement in stage of continental margin disjoined. Ondor Sum Group of Meso-Neoproterozoic and oceanic crust association consists of ultrabasic rock, basic Volcanic rock and silicilith interpreted as extended transition crust during continental margin extension disjoined in Meso-Neoproterozoic era to Early Paleozoic. This region's tectonic regime transformed from extension to compression in late Early Paleozoic to early Upper Paleozoic. Ophiolitic melange belt and large amont of altered diorite, tonalite, granodiorite, monzonitic granite and kaligranite could be interpreted as compression type transition crust during compression in Upper Paleozoic.