北天山山前安集海河阶地形成的时代及意义

北天山山前几条主要河流普遍发育河谷阶地。安集海河发育６～８级阶地，通过年代测定及区域对比，可得出安集海河阶地形成于中更新世晚期一晚更新世早期（约１２～１４万年左右）。第四纪以来构造活动及气候变化控制着河流下切和侧蚀作用的进行，安集海河阶地的形成和发育明显受第四纪晚期构造活动和气候变化等因素的影响。

Formation of the Anjihai River Terraces at the North Tianshan Piedmont, Xinjiang, and Significance

Terraces are commonly developed in several rivers at the North Tianshan piedmont. There are 6 to 8 terraces in the Anjihai River. Based on the age dating and regional geological correlation, the Anjihai River terraces were formed in the late Middle to early Late Pleistocene (ca. 140 to 120 ka ago). The main factors affecting the formation and development of the river terraces were late Quaternary tectonic activities and climatic changes. The local tectonic activity and climatic change controlled the changes of the relative height and number of river terraces at the North Tianshan piedmont.