摘要
本文在野外考察的基础上，结合室内粒度和石英氧同位素含量分析，讨论了西昆仑山典型地区晚新生代不同时期沉积的搬运机制、沉积环境和物质来源对粒度参数和石英δ^（１８）值的影响。
This paper, based on the field investigation with analyzing and studying the grainularity features and quartz's isotope content of the sediments, discusses the effects of transport mechanism, sedimentary environment and material sources of the moraine drift and fluvioglacial sediments for different geological periods, lacustrine sediments and loess from the typical regions of the West Kunlun Mountain, N_2 and Q_1 sediments developed in the perimountain region of the Kunlun Mountain and Kashi Basin, the grain parameters and quartz's δ(18)O values. The results show that the sediment features of different times and types have not only the sameness, but also the respective characteristics. The sameness (fine-grained materials) are: whether in the profiles or in the regions, (1) the similar mean granularity and skewness, which reflect the similarity of material sources and sedimentary environment; (2) the poor sorting, because these sediments were not strongly modified by wind and water after they deposited on the other hand, the material composition is fine, so the effect of secondary modification is not remarkable; (3) narrow to medium kurtoses, which reflect they came from the unitary material sources. The sedimentary features are: (1) The materials of moraine drift are from boulder to clay, have double modes because of strong transport force and rapid sedimentary speed, and their oxygen isotopes in different regions vary in a larger range, and are unanimous with their underlying bedrock composition, which shows that the material sources are the local sites; (2) Fluvioglacial and lacustrine sediments, because the transport force was relatively weak and they were developed from the moraine drift, are mainly fine-grained materials, the sorting is also better than the moraine drift from the relevant time; (3) The grain parameters and oxygen isotopes of loess from different regions are unanimous, which indicates that the material sources are homogeneous and external; (4) The difference between N_2 and Q_1 sediments, in macroscopic distribution, microscopic composition as well as oxygen isotopes, shows their distinct material sources, geological forces and sedimentary environment.
出处
《干旱区地理》
CSCD
北大核心
1999年第2期50-55,共6页
Arid Land Geography
