摘要
对滇中小江走滑剪切带中的挤压变形作用进行研究发现，尽管这些变形多发生于中元古界昆阳群浅变质岩中，其形成时代却可能是第三纪末和第四纪初，和小江断裂带的走滑运动有成因关系，并导致了走滑位移量的衰减。昆阳群的隆起可能主要是第四纪变形的结果。
Central Yunnan is cut in a N-S direction by the highly active Xiaojiang faultsystem, which initiated left-lateral movement in the late Tertiary-early Quaternary.Our study found that the crust along the fault system has been shortened significantly in a N-S direction. In the Huidong area, the Proterozoic low-grade metamorphic rocks (Kunyang group) and Sinian rocks have been emplaced above Jurassicand Paleogene red beds along a southly dipping thrust fault. As a result, the uplifted crust forms the highest mountain massif in the region. The spatial and temporal relationships between the thrust faults and the strike-slip faults indicate that thecrustal shortening and left-lateral movement are associated with eath other. Dueto the absorbption of the strike-slip movement by the thrust movement, the amountof left-lateral diplacement along the Xlaojiang fault sharply decreases from 60kmnorth of the thrust belt to 30km to the south. In the area of Anning and Tianba,along the Puduhe failt, a main branch of the Xiaojiang fault system, rocks of Proteroozoic, Sinian and Paleozoic ages are piled up and tectonically underlain by theJurassic red beds along several north-dipping thrust faults. Many klippen and structural windows are present along the faults. The termination of the Puduhe faultcan probably be ascribed to the tectonic transformation.The high relief regions in central Yunnan are often bounded by the similarthrust faults, Therefore, the uplft of the Proterozoic low-grade metamorphic rocksand other old rocks occurred in these regions was caused by late Cenozoic deformation.
出处
《地质科学》
CAS
CSCD
北大核心
1995年第3期209-219,T002,共12页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
云南省科学应用基础研究基金
云南省科委国际科技合作项目
关键词
走滑断裂
构造窗
剪切带
挤压变形
晚新生代
South-eastern periphery of the Tibetan Plateau, Kunyang group,Strike-slip fault, Structural window, Tectonic transformation
