滇西陇川盆地形成机制

FORMATION MECHANISM OF LONGCHUAN BASIN IN WESTERN YUNNAN

陈布科 赵永胜 邝平河 钟九成

Chen Buke Zhao YongSheng Kuang Pinghe Zhong Jiucheng

陇川盆地是上第三系微型箕状断陷盆地,是在滇西区域压扭背景上产生的右旋张扭力学机制条件下,经过早期拉分作用、中期右旋张扭以及后期拉张-挤压复合作用形成的拉分-走滑盆地.这一模式在某种程度上也可解释云南怒江以西第三系微盆地群的形成机制.

Longchuan Basin is a continental Tertiary microbasin developed on Cambrian metomorphic basement. The deposits are mainly coarse fluviolacustrine debris. In the basin, colluvial fan, alluvial fan and fan delta are well developed.The basin can be divided into uplift-overlap belt in the southwest, fault-depression belt in the central part, fault-block belt in the mid-western part and slope overlap belt in the northwest.The Longchuan I3asin is a half-grabed controlled by comtemporaneous boundary faults formed by crest collapse. It is considered that the basin is a pull-apart and strike-slip basin resulted from multi effects through pull-apart action in the early stage, tenso-shearing in the middle stage and superimposition in the late stage under dexdral tenso-shearing mechanics. The evolution of the basin underwent rapidly faulted depression in the early stage, stable development in the middle stage and shrivelling in the late stage. In some extent, this mode can be used to explain the formation mechanism of many Tertiary microbasins in the westward of the Nujiang River in Yunnan Province.

10.11743/ogg19940406