Grain-size and compositional variability of Yarlung Tsangpo sand(Xigaze transect,south Tibet):Implications for sediment mixing by fluvial and aeolian processes  

作　　者：Wen Lai Wen-Dong Liang Xiu-Mian Hu Eduardo Garzanti Hua-Yu Lu Xiao-Long Dong 

机构地区：[1]Frontiers Science Center for Critical Earth Material Cycling,School of Geography and Ocean Science,Nanjing University,Nanjing 210023,Jiangsu Province,China [2]State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,Sichuan Province,China [3]State Key Laboratory of Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,Jiangsu Province,China [4]Department of Earth and Environmental Sciences,Universita di Milano-Bicocca,Milano 20126,Italy

出　　处：《Journal of Palaeogeography》2023年第2期195-210,共16页古地理学报（英文版）

基　　金：supported financially by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019QZKK0204);the National Natural Science Foundation of China Project(Grant No.4200020124);the Jiangsu Shuangchuang(Mass Innovation and Entrepreneurship)Talent Program(Grant No.JSSCBS20210014)。

摘　　要：Studying the grain-size dependent compositional variability in modern river sediments provides a key to decipher the information stored in the sedimentary archive and reconstruct the evolution of the Earth’s surface in the past. Bedload sand along the Xigaze cross section of the Yarlung Tsangpo(upper Brahmaputra River) ranges in mean grain size from 0.72 Φ to 3.21 Φ, is moderately to poorly sorted and slightly platykurtic to moderately leptokurtic with sub-angular to sub-spherical grains. Litho-feldspatho-quartzose to feldspatholitho-quartzose sand(Q 43%-65%;F 13%-44%;L 11%-28%) contains 3.4%-14.4% heavy minerals including amphibole(64%-89%), epidote(4%-11%), chloritoid(0-10%), and clinopyroxene(2%-6%). The marked textural and compositional variability observed across the Xigaze transect of the Yarlung Tsangpo mainstem is controlled by both fluvial and aeolian processes, including repeated reworking by westerly and glacial winds,as well as by local contributions from northern and southern tributaries draining the Lhasa Block and the Himalayan Belt, respectively. The modern sedimentary case here will shed new light on interpreting paleogeography and provenance.

关 键 词：Modern fluvial sediments Sand petrography Heavy minerals Fluvial/aeolian interactions Endmember grain-size modeling Lhasa Block Himalayan Belt 

分 类 号：P618.13[天文地球—矿床学]