摘要
海原断裂带作为青藏高原东北缘构造变形最显著断裂带之一,记录了青藏高原向北东扩展的构造信息。在详细的构造测量基础上,初步提出海原断裂带新生代以来的古构造应力场序列,反演了其新生代构造演化历史。详细构造解析表明,海原断裂带新生代以来主要经历了5个构造演化历史阶段,即始新世—中新世NW SE向构造伸展与沉积盆地发育、中新世晚期—上新世NNE SSW向构造挤压与海原断裂带右行走滑活动、上新世末—早更新世NE SW向构造挤压与强烈褶皱逆冲活动、晚更新世晚期以来ENE WSW向构造伸展与断陷盆地发育、全新世以来NE SW向构造挤压作用与断裂带强烈左行走滑活动。变形分析表明海原断裂带现今地貌格局主要缘于上新世末—早更新世NE SW向强烈逆冲活动,后期ENE WSW向构造挤压作用导致断裂走滑活动,并改造了局部地貌,主要表现为沿断裂带发育一系列第四纪小型拉分盆地。该带新生代构造演化研究,为探讨青藏高原东北缘新构造演化提供了具体构造证据。
The Haiyuan fault zone,one of intensive deformational zones in the northeastern Tibetan Plateau,records the information about the northeastward growth of the Tibetan Plateau.On the basis of detailed structural measuring,we proposed the sequences of the Cenozoic paleo-stress fields and the tectonic evolution of the Haiyuan fault zone.Our studies show a five-stage tectonic evolution as follows.The first was the widespread development of the basins along the Haiyuan fault zone from the Eocene to the Miocene due to the NW SE extension;secondly,the Haiyuan fault zone was featured by right strike-slip activity in the late Miocene to the Pliocene controlled by the NNE SSW compression;thirdly,the fault intensively thrusted northeastward in the Late Pliocene to the Early Pleistocene owing to the NE SW compression,which resulted in the geomorphic formation;fourthly,Late Pleistocene basins occurred,caused by the NE SW extension;lastly,Haiyuan fault zone was marked by sinistral strike-slip movement since the later Late pleistocene,and some pull-part basins formed along the fault.The neotectonics of the Haiyuan fault zone will provide some new structural evidences for probing the northeastward extending of the Tibetan Plateau.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第4期1-17,共17页
Earth Science Frontiers
基金
中国地质调查局地质调查项目(1212011120100
1212011120099)
关键词
青藏高原东北缘
海原断裂带
构造应力场
新生代
构造演化
Northeastern Tibetan Plateau
Haiyuan fault zone
stress field
Cenozoic
tectonic evolution
作者简介
施炜（1971-），男，副研究员，构造地质学专业，主要从事中、新生代构造研究。Email：shiweinmg@163．com
