小江断裂带南段新寨盆地新构造运动特征

Characteristics of Neotectonic Movement in Xinzhai Basin in the Southern Section of Xiaojiang Fault Zone

小江断裂带是新构造时期以来十分活跃的活动断裂带,沿线地震活动频繁,新寨盆地是其控制下发育的串珠状盆地之一。通过野外第四纪地质与构造地质填图,LiDAR扫描,无人机移动摄影测量等手段,对新寨盆地内部第四系地层分布和控盆断裂以及其反映的构造活动期次进行研究,认为新近纪以挤压为主的应力过后,早更新世晚期小江断裂南段受元谋运动影响开始强烈左旋走滑运动,新寨盆地受其控制开始发育,全新世以来,断层偏离原先构造位置再次活动,具有一定的新生性和发震能力,晚更新世存在一个活动间歇期。

The Xiaojiang fault zone is a very active fault zone since the neotectonic period.There are frequent seismic activities along the line.The Xinzhai Basin is one of the beaded basins developed under its control.By means of field Quaternary and structural geological mapping,LiDAR scanning,UAV mobile photogrammetry and other methods,this paper studies the distribution of the Quaternary strata and the basin-controlling faults in the Xinzhai Basin and the tectonic activity periods reflected by them,and believes that after the stresses dominated by compression in the Neogene,the southern segment of the Xiaojiang fault in the late Early Pleistocene began to undergo a strong left-lateral strike-slip movement under the influence of Yuanmou movement,and the Xinzhai Basin began to develop under its control.Since the Holocene,the fault has deviated from its original structural position and moved again,with a certain degree of newness and seismogenic ability,and there is an intermittent period of activity in the Late Pleistocene.