雅鲁藏布江上游支流沉积物的矿物组成特征  

Mineral composition characteristics of sediments from different tributaries in upper reaches of the Yarlung Zangbo River

作　　者：罗豪 彭辉[1] 刘佳[1] 肖尚斌[1] 严登华[2] 刘心庭 LUO Hao;PENG Hui;LIU Jia;XIAO Shangbin;YAN Denghua;LIU Xinting(College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,Hubei,China;Department of Water Resources,China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Hubei Three Gorges Polytechnic,Yichang 443000,Hubei,China)

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]中国水利水电科学研究院水资源研究所,北京100038 [3]湖北三峡职业技术学院,湖北宜昌443000

出　　处：《冰川冻土》2023年第5期1451-1462,共12页Journal of Glaciology and Geocryology

基　　金：第二次青藏高原综合科学考察研究项目(2019QZKK0207-02-05)资助。

摘　　要：本文对青藏高原内气候和地貌方面具有典型意义的雅鲁藏布江上游支流沉积物进行矿物组成分析和粒度分析,根据其组合分布特征,对比了各支流之间及各支流内的矿物差异,并对沉积环境及其主控因素进行了初步分析。结果表明,雅鲁藏布江上游河流沉积物类型主要为砂质粉砂,河流沉积物的矿物组成特征可归为三种类型:①列荣藏布-来乌藏布-柴曲型,以斜长石、钾长石、石英为主;②则拉色登曲-雄曲型,以方解石、伊利石、石英为主;③索曲型,以斜长石、石英、伊利石为主。雅鲁藏布江上游不同支流沉积物的矿物空间分布受源区基岩性质控制,但是各支流内的矿物及其组合的差异更主要反映河流水动力强度与沉积环境的差异,即重力分选作用;同时,寒冷的气候条件制约了研究区的化学风化作用。Due to the difference from material source,grading function between sediment transportation and de⁃position,and weathering processes,the grain sizes in river sediments are often quite different.Therefore,sedi⁃ment source tracing or sedimentary environment reconstruction can be carried out based on the differences in the geochemical characteristics and mineral composition of the different grain grades in the sediment.To clarify the river sedimentary environment and its main controlling factors,the Yarlung Zangbo River was selected as the study area,which is typical in terms of climate and geomorphology within the Qinghai-Xizang(Tibet)Plateau.Whole-rock mineral X-ray diffraction analysis and particle size analysis were carried out on the sediments of trib⁃utaries from the upper Yarlung Zangbo River,while the mineral differences between and within the tributaries were compared according to the distribution characteristics of their mineral assemblages.The results showed that the river sediments in the upper reaches of the Yarlung Zangbo River were mainly silty sand,and the mineral ma⁃turity of the tributaries was low.The mineral characteristics of different tributaries were different,which could be classified into three types:①Lierong Zangbo-Laiwu Zangbo-Chai River type,mainly consisting of plagio⁃clase,potassium feldspar and quartz;②Zelasedeng River-Xiong River type,dominated by calcite,illite and quartz;③Suo River type,dominated by plagioclase,quartz and illite.The spatial distribution of sediment min⁃erals from different tributaries was controlled by the nature of source area bedrock,but the differences in miner⁃als and their combinations from each tributary mainly reflected the differences in hydrodynamic intensity and sed⁃imentary environment rivers,that was,gravity sorting.At the same time,the cold climatic conditions restricted the chemical weathering in the study area.

关 键 词：雅鲁藏布江 矿物分析 物质来源 沉积环境 

分 类 号：P512.2[天文地球—地质学]