新疆河谷阶地的年代

DATE OF VALLEY TERRACES IN XINJIANG

对新疆阿尔泰山、西准噶尔山地、天山南北及昆仑山２６ 条河流河谷阶地的年代学研究表明：高河漫滩主要形成于晚全新世时期３ ０００ ａＢ．Ｐ．；Ⅰ级阶地形成于中全新世时期６ ０００ ａＢ．Ｐ．；Ⅱ和Ⅲ级阶地形成于晚更新世晚期１３ ０００～３４ ０００ ａＢ．Ｐ．；Ⅳ级以上阶地形成于晚更新世早期６７ ０００～９５ ０００ ａＢ．Ｐ．。这些地貌面的年代是第四纪重要地质事件出现的时期。阶地高出河床的高度（Ｈ）与其相应的形成年代（Ａ）有较好的线性对数关系。

By studying the ages of valley terraces of 26 rivers at Altai Mountain, West Jungeer Mountain,southern and northern Tianshan, and Kunlun Mountain, it is indicated that high alluvial flats were mainly formed in 3 000 aB.P. of Late Recent, first order terraces in 6 000 aB.P. of Middle Recent, second and third order terraces in 13 000~34 000 aB.P. of late Late Epileistocene, and the forth or more order terraces in 67 000~95 000 aB.P.of early Late Epileistocene. These ages of the geomorphic surfaces were the periods in which important Quaternary' s geological events took place. In addition, there is a better linear logarithmic relation between the height (H) of a terrace over river bed and its corresponding formation age (A).