新疆伊犁盆地西北缘红山嘴断裂特征与最新活动

红山嘴断裂位于新疆霍城县,是伊犁盆地北缘前陆褶冲带的前锋断裂。断裂走向NWW,倾向NNW。野外地质调查表明,断裂在地表主要表现为高角度逆冲断层,倾角超过50°。断裂上盘主要由新近系红层组成,下盘为上更新统黄土和全新统。综合野外地层接触关系和区域构造研究表明,红山嘴断裂可能形成于早更新世末,错断地层表明红山嘴断裂在晚第四纪以来发生过强烈的活动,最新活动表现在断错全新统松散砂砾石层。

Characteristics and latest activity of Hongshanzui fault in northwestern Yili basin, Xinjiang Province

Located in Huocheng, Xinjiang, the Hongshanzui fault is a frontal fault of the fold-and-thrust belt developed in the foreland area on the northern margin of Yili basin. The fault strikes NWW and dips NNW. Field observations show that this fault is a steep reverse fault with dip angle over 50°. The hanging wall of the fault consists of Neogene red beds, whereas upper Pleistocene loess and Holocene sediments are exposed on the footwall. According to the contact relationship and regional structure in the study area, the fault might have been formed at the end of Early Pleistocene. Disrupted strata along Hongshanzui fault indicate intensive activities since Late Quaternary, and hence the latest activity of this fault in Holocene and disrupted gravel and sand beds at the surface also deserve much attention.