中始新世(45Ma),新特提斯洋闭合,印度板块与欧亚板块碰撞。作为这一事件的陆内效应,滇西南地区沿先期断裂发生北北东向的逆冲推覆,兼具右行走滑。位于澜沧江断裂、酒房断裂和无量山-营盘山断裂之间的地区发生沉降形成走滑挤压盆地。盆地为冲积扇和河流相沉积物所充填。根据沉积特征分析,澜沧江断裂和酒房断裂组成上叠式逆冲系,无量山-营盘山断裂右行滑移50km。盆地的形成演化与青藏高原及东亚地区的区域性构造事件具有明显的耦合关系。
走滑挤压盆地
陆－陆碰撞
云南省西南部
Abstract:
In middle Eocene (45Ma),the Indian continent collided with the Asian continent,resulting in oblique compression and dextral strike slipping in southwestern Yunnan,China.Controlled by the Lancangjiang,the Jiufang and the Wuliangshan-Yingpanshan faults,a transpressional basin was formed.It was filled by alluvial and fluvial deposits.The Jiufang and the Lancangjiang faults on the west thrusted successively to NEE,forming an overstep thrust sequence.On the east,the Wuliangshan-Yingpanshan fault right-laterally displaced about 100 km.The development of the basin was closely related to tectonic evolution of Tibet and Southeast Asia.
Key words:
Transpressional basin
Continent-continent collision
Paleogene
Southwest Yunnan
