晚更新世以来南天山阿克苏地区地壳缩短率

作者研究南天山中段阿克苏—库车山前带活动断层,发现断层切过托木尔峰山麓第四纪冰碛物和阶地,形成2条断层崖。通过测量阶地和冰碛物的变形量,推断阶地和冰碛物的沉积年代,估算南天山中段阿克苏地区晚更新世以来的地壳缩短率可能为1.85mm/a。这个缩短率与库尔勒地区(2mm/a)和柯坪地区(1.8mm/a)的地壳缩短率一致,但是小于南天山西段喀什地区(10±2mm/a)和天山东段玛纳斯地区(6±3mm/a)的地壳缩短率,表明天山不同地段的地壳缩短率存在明显差异。

SHORTENING RATE SINCE LATE PLEISTOCENE IN AKSU AREA, SOUTHERN FLANK OF TIANSHAN, CHINA

We studied geometries and rates of active thrust faulting and folding in the Aksu Kuche area along the southern flank of the Tianshan Mountains Our fieldwork reveals that the active thrust reaches the surface near the south front of the mountain belt, and that two fault scarps are clearest across terraces and moraines along both sides of the Tailan river in the Tomur area, north of Aksu The inferred their ages for the terraces and moraines, together with heights of fault scarps that cut them, imply a shortening rate of 1 85 mm/a on the Aksu area since Late Pleistocene This rate, similar to that of the Korla area (2mm/a) on its east side and the Kaping area (1 8 mm/a) on its west side, but lower than that of the Kashgar area (10?2 mm/a)farther west and that of the Manas area (6?3mm/a) in the northern margin of the belt, implies that the distribution of shortening across the Tianshan changed markedly along the belt.