摘要:
甘肃北山地区早古生代蛇绿岩受阿尔金北东向左行走滑断裂影响,被分割成白云山—洗肠井蛇绿岩段、通畅口—牛圈子蛇绿岩段、白玉山—红柳河蛇绿岩段。牛圈子蛇绿岩属洋壳型蛇绿岩,蛇绿岩各单元岩石发育齐全,与东部洗肠井洋壳型蛇绿岩和西部红柳河洋壳型蛇绿岩相似,牛圈子蛇绿熔岩Rb-Sr同位素年龄为463±18Ma,与洗肠井蛇绿熔岩夹层中放射虫时代一致,为中奥陶世—晚奥陶世早期,红柳河蛇绿岩尚无可靠时代依据。通过构造恢复,上述3条蛇绿岩段在早古生代为统一的早古生代蛇绿岩带,这条早古生代蛇绿岩带属早古生代塔里木板块和哈萨克斯坦板块间的缝合带。
Abstract:
The ophiolite of early Paleozoic time of Beishan in Gansu,affected by the Aljin NE left-lateral strick-slip fault,is divided in to three sections which are Baiyun shan-Xichangjing, Tongchangkou-Niuquanzi and Baiyu shan-Hong liuhe section.Niuquanzi ophiolite,developed all units of ophiolite and resembling eastern Xichangjing and western Hongliuhe ophiolite belonging to the type of oceanic crustop hiolite,is also the type of oceanic crustop hiolite. Its Rb-Sr isotope age is 463±18 Ma(middle Ordovician-early stage of late Ordoviaian),the same as age of Rediolaria in band of Xichangjing ophiolite and that of Hongliuhe ophiolite hasn't been determined.Recovering the tectonic,this three secsions are one ophiolite zone of early Paleozoic.And it is a stylolitic zone between Tarim and kazakh stan missif in Early Paleozoic.
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