【摘要】 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。更多还原

【Abstract】 Western Beishan mountain is in the join part of the three Precambrian continental blocks of Talim, Qaidam and North China(Alashan), and is also the complex stacking reworked part of the three Phanerobiotic orogeny belts of Tianshan, Qianlian and Altyn Tagh. In recent years, the new discovery of Neoproterozoic eclogite and granite and detailed researches on the Neoproterozoic pegmatitie dyke swarm, dolerite dyke swarm and Sinian un metamorphic sedimentary cover in this area can reveal the framework of assembly and crack events of the above continental blocks. In the early Neoproterozoic, the oblique converge might develop between the blocks of Talim and Qaidam and sealing by deep level ductile shear zone, and the crystallization age of 913 Ma (U Pb ) of syn shear pegmatite dyke swarm may represent the time of this event. Then in the ages of 860～880 Ma,violent collision took place between Talim block and an unclear block(North China block or Alashan block can’t be determined) with the formation of eclogite(the metamorphic age of 860 Ma )and grinite belt (the crystallization age of 880 Ma) in the Liuyuan area of the north margin of Talim block. After the collision, the crack developed in the united continent represented by two period of intruding of dolerite dyke swarm,. With the extension develop gradually, the paleaogeography evolution develops to the stage of sedimentation of continental psepholite and marine carbonate in the time about 700 Ma represented by the Sinian Ananba formation.更多还原