内蒙古阿拉善西南缘早前寒武纪地质研究进展

阿拉善地块西南缘的早前寒武纪变质基底主要分布在内蒙古阿拉善右旗与甘肃河西走廊相交界的龙首山—北大山地区,在大地构造上该区是华北克拉通、塔里木克拉通和祁连造山带3个地体的交汇处,因此长期以来备受关注。笔者综合了近十年来中外地质学家对阿拉善地块早前寒武纪地质的研究成果,对已取得的资料成果进行分析整理,从岩石单元划分、年代学、构造边界及大地构造归属4个方面进行论述,总结了近年来对以龙首山岩群为代表的阿拉善地块西南缘早前寒武纪变质基底的研究进展,提出目前争议性较大的问题,并探讨今后进一步研究的方向。

STUDY PROGRESS OF THE PRECAMBRIAN METAMORPHIC BASEMENT IN SOUTHWESTERN MARGIN OF ALXA BLOCK

Precambrian metamorphic basement in Southwestern Alxa Block is located Longshoushan and Beidashan area, including Alxa Right Banner of Inner Mongolia and north part of the Hexi Corridor in Gansu. Tectonic setting of the area is the intersection of North China Craton, Tarim craton, the Qilian terrane and Central Asian Orogenic Belt （CAOB）. In this contribution, the authors integrated the recently published Preeambrian geological studied results of the Alxa Block and analyzed these data completely. These results which have been obtained data were analyzed and sorted. From four aspects （division of rock unit, geochronology, tectonic boundary and attribution） are discussed, and summarize for recent research progress on Precambrian metamorphic basement of the southwestern margin of Alxa Block, such as a representative of Longshoushan group. The authors make the controversial issues and point out the directions for further research.