【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。更多还原

【Abstract】 Due to the difference from material source, grading function between sediment transportation and deposition, and weathering processes, the grain sizes in river sediments are often quite different. Therefore, sediment 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 tributaries 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 maturity of the tributaries was low. The mineral characteristics of different tributaries were different, which could be classified into three types:(1) Lierong Zangbo-Laiwu Zangbo-Chai River type, mainly consisting of plagioclase, potassium feldspar and quartz；(2) Zelasedeng River-Xiong River type, dominated by calcite, illite and quartz；(3) Suo River type, dominated by plagioclase, quartz and illite. The spatial distribution of sediment minerals from different tributaries was controlled by the nature of source area bedrock, but the differences in minerals and their combinations from each tributary mainly reflected the differences in hydrodynamic intensity and sedimentary environment rivers, that was, gravity sorting. At the same time, the cold climatic conditions restricted the chemical weathering in the study area.更多还原