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甘肃北山西部地处塔里木、柴达木和华北 (阿拉善 )三个前寒武纪地块的交汇部位 ,是受显生宙天山造山带、祁连造山带和阿尔金造山带多次叠加改造的地区。近几年 ,随着新元古代榴辉岩、花岗岩的新发现 ,结合新元古代伟晶岩脉群、辉绿岩墙群和震旦纪未变质沉积盖层 ,初步确定了该地区新元古代陆块汇聚与裂解的地质事件框架。在新元古代早期 ,塔里木地块与柴达木地块可能发生斜向汇聚 ,并以深层次韧性剪切带进行焊接 ,其时间在 913Ma左右。稍后 ,在塔里木地块北部的柳园一带 ,塔里木地块与另一个地块发生碰撞 ,形成了榴辉岩和大面积带状分布的花岗岩 ,其时间在 86 0～ 880Ma左右。之后 ,在经过汇聚的大陆块内部发生裂解 ,形成了两期辉绿岩墙群。随着裂解作用的进一步加强 ,该地区进入到陆相砂砾岩和海相碳酸盐沉积阶段 ,形成了安南坝群沉积建造 ,其时间在 70 0Ma左右。
The western part of Beishan in Gansu is located at the intersection of the Tarim, Qaidam and North China (Alxa) Precambrian plots and is superimposed and rebuilt several times by the Phanerozoic Tianshan orogenic belt, the Qilian orogenic belt and the Altun orogenic belt Area. In recent years, with the new discovery of Neoproterozoic eclogite and granite, combined with the Neoproterozoic pegmatite, diabase dykes and the Sinian unconformably sedimentary caprock, the new element Geological event framework of ancient land mass convergence and. In the early Neoproterozoic, the Tarim block and Qaidam block may occur oblique convergence, and the deep ductile shear zone for welding, the time is about 913Ma. Later, in the vicinity of Liuyuan in the northern part of the Tarim block, the Tarim block collided with another block to form eclogites and large-scale belt-shaped granites with a time ranging from 86 0 to 880 Ma. After that, cracking occurred within the converged mainland block, forming two diabase dikes. With the further strengthening of the cleavage, the area entered the sedimentary facies of continental glutenite and marine carbonate, forming the deposition of Annanba group, with a time of about 70Ma.