西藏阿里地区札达盆地第四纪砾石统计及其意义

Analysis of Quaternary gravels in the Zhanda basin, Ngari area, Tibet, China.

通过对西藏阿里札达盆地第四纪砾石层的砾组分析,以及对从基岩地层和第四纪砾石层的砾性、砾石粒度、砾态和砾向分析,阐述了札达盆地象泉河流域河流阶地和香孜地区第四纪砾石层的来源、成因、搬运方式及当时的水动力条件、古水流流向。研究表明,札达盆地的砾石层主要来源于盆地上部河湖相地层,砾石的风化程度普遍较低,象泉河流域古水流方向大致与现代河流的流向一致,伴随着青藏高原的整体隆升,象泉河流量有减小的趋势。

The authors expound the sources, origins, modes of transport, hydrodynamic conditions and paleoflow directions of different Quaternary gravel beds on terraces in the Xiangquan River valley and Qangzê area in the Zhanda basin, Ngari area, Tibet, from a fabric analysis of the Quaternary gravel beds and analyses of the composition, particle size, shape and preferred orientations of gravels in the bedrocks and Quaternary gravel beds. Studies indicate the following: gravels of the gravel beds of the Zhanda basin mainly came from fluvio-lacustrine strata upstream of the basin. The weathering degree of the gravels is generally low. The paleoflow direction of the Xiangquan River valley was approximately the same as that of modern rivers in the valley. The flow of the Xiangquan River has had a tendency to decrease with the wholesale uplift of the Qinghai-Tibet Plateau.