中文摘要：

塔里木盆地腹地的麻扎塔格剖面出露了连续的晚新生代地层，深入研究其沉积环境对认识塔里木盆地西部沙漠的形成演化有重要意义．对剖面全部样品进行粒度测试，应用粒度分布函数拟合方法进行粒度组分分离，依据组分的粒径／含量一频率变化，结合岩性判断，系统分析了沉积序列粒度组分的成因．粒度组分分析结果显示：风成沉积中超细粒、细粒粉尘、粗粒粉尘、风成砂组分粒径范围分别为〈1．9、1．9~8．6、8．6~33-3、33．3~270．0μm．湖相沉积常呈双峰分布，湖相悬移粒径为2．4～8．6gm，含量〉60％，叠加超细粒组分；河流沉积中河流砂粒径〉270．0岬．剖面620m处大套风成砂沉积出现，对应3．4Ma风成组分含量显著增大，指示了塔克拉玛干沙漠的出现，420m后风成砂沉积占据主导，对应2．8Ma之后风成砂组分含量及粒径显著增大，指示沙漠环境进一步扩张．3．6Ma以来河流组分含量阶段性增大，指示了多期河流发育，可能与青藏高原隆升有关．

英文摘要：

Continued late Cenozoic sedimentary strata were exposed at the Mazatagh section in central Tarim Basin. An in-depth study of its sediment environment would be of great significance for under- standing the desert formation and evolution in the western Tarim Basin. For this purpose grain size mea- surement was carried out for all samples, grain-size component analysis was conducted of the component partition, and the origin of each component was systematically analyzed on the basis of the size/propor- tion-frequency data, combined with field lithology. The results of component analysis suggested that, for the aeolian sediments, the modal-size of ultralfine component, fine suspension dust, coarse suspension dust and aeolian sand component had a range of〈1.9, 1.9-8.6, 8.6-33.3, 33.3-270.0 μm, respectively. La- custrine sediments generally had a bimodal distribution, lacustrine suspension a modal size range of 2.4- 8.6 μm, and the proportion was 〉60%, being overlapped by an ultralfine component. The modal size of fluvial sand component in the fluvial sediment was over 270.0 μm. Large-scale aeolian sand appeared at 620 m in the section, corresponding to a significantly increased aeolian component proportion at 3.4 Ma, indicating the onset of the Taklimakan Desert; aeolian sand dominanted the sediment after 420 m, corre- sponding to a significantly increasing proportion and grain-size of aeolian sand component at 2.8 Ma and indicating further expansion of the desert environment. The proportion of fluvial component periodically increased after 3.6 Ma, indicating the occurrence of several periods of fluvial development, probably re- lated to the uplift of the Tibetan Plateau.