塔里木河干流古河道表层沉积物粒度特征及其意义  

Grain Size Characteristics and Their Significance for Surface Sediment of Paleochannels Along Main Stream of Tarim River

作　　者：李开封[1,2,3] 穆桂金[1,3] 徐立帅[1,2] 潘光耀[1,2] 

机构地区：[1]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院研究生院,北京100049 [3]新疆策勒荒漠草地生态系统野外研究站,新疆策勒848300

出　　处：《水土保持通报》2012年第1期161-164,共4页Bulletin of Soil and Water Conservation

基　　金：国家科技支撑计划"南疆三地州生态环境整治技术集成与应用推广模式开发"(2009BAC54B05)

摘　　要：历史上塔里木河因频繁改道在干流两岸遗留了多条古河道,研究其表层沉积物粒度特征,可判断表层沉积物形成时的沉积环境与水动力条件。通过对塔里木河古河道表层沉积物系统采样,进行粒度分析发现:(1)塔里木河古河道表层沉积物优势粒级为粉沙,粒度次一级组分在干流两岸古河道间差异明显;(2)古河道表层沉积物比塔里木河洪泛平原土壤粒径细小,表明古河道晚期水动力较弱;(3)塔里木河干流南岸的部分古河道表层沉积物中,含风成沙夹层,反映了其沉积环境受风水两相作用。Historically,many paleochannels formed along the current main stream of Tarim River due to frequent migrations.Research on the grain size characteristics in surface sediment of the paleochannels is helpful to determine the sedimentary environments and hydrodynamic conditions during the surface sediment formation.Through systematic samplings and grain size analysis for surface sediment of the paleochannels,we find that：（1） silt is the dominated grain fraction in surface sediment of paleochannels and the secondary grain composition is obviously different between the south and north paleochannels along the current main stream;（2） the grain size for surface sediment of the paleochannels is smaller than that for surface soils in the floodplain of Tarim River,which suggests that hydrodynamics was relatively weak in the late period of paleochannels formation;（3） there are eolian sand layers in surface sediment of some paleochannels on the south bank of Tarim River,which implies that the sedimentary environments were influenced concurrently by wind and water.

关 键 词：塔里木河 古河道表层沉积物 粒度 

分 类 号：P931.1[天文地球—自然地理学]