摘要
青藏高原新生代变形隆升过程是青藏高原新生代构造演化研究的热点问题,地处于高原东北部祁连山东北缘的榆木山是研究高原变形隆升时空过程的关键研究区之一。榆木山地区发育了一套粗砾相磨拉石——玉门砾岩,磁性地层研究表明其底部地质年代约为3.58Ma。经古水流、磁化率、野外考察等推断玉门砾岩可能主要为构造隆升的产物,同时在榆木山地区还发育3个与玉门砾岩有关的不整合面,其跨越年龄分别约为:5.23～3.58Ma、2.88～2.58Ma和<1.77～0.8Ma。综合分析认为该地区变形隆升不晚于3.58Ma,之后至少经历两期构造变形隆升,该结果比北东向分步生长变形隆升模式推测的变形隆升时间明显早约1Ma,应该是对高原东北部青藏-昆黄运动的响应结果。
The Cenozoic deformation and uplift of the Tibetan Plateau is a hot issue in recent study of earth science. The Yumu Shan, located in the northeastern margin of the Qilian Shan, northeast Tibetan Plateau, is the key area for deciphering the spatio-temporal evolution of the entire plateau. The thick molasse （Yumen conglomerate） deposited in the Yumushan region, with bottom age of ~3.58 Ma by the magneteostratigraphy. Based on the paleocurrents, magnetic susceptibility, field research and published results, the Yumen conglomerate was likely the product of tectonic uplifting, and three unconformities related to the Yumen conglomerate were developed with age ranging from 5.23~3.58, 2.88~2.58, and ~ 1. 77 ~0. 8Ma, respectively. Integrated study suggests that the uplift and deformation of the Yumushan region was not later than 3.58 Ma, experiencing at least two successive tectonics events. Our result is one Ma earlier than time of deformation and uplift, which was inferred from northward growth model of the Tibetan Plateau, and should be part response of Qingzang-Kunhuang Movement in the northeastern part of the plateau.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2012年第6期898-905,共8页
Acta Geologica Sinica
基金
国家自然科学基金(编号41021001
40921001)
中国地质科学院地质研究所基本科研项目(编号J1112)联合资助的成果
关键词
榆木山
磁性地层
玉门砾岩
青藏高原变形隆升
Yumushan
magneteostratigraphy
Yumen Conglomerate
deformation and uplift of theTibetan Plateau
