中文摘要：

对成都粘土以及相邻的川西黄土（青藏高原东部黄土）和北部黄土（秦岭山地及黄土高原黄土）的石英粒度分布和石英表面微结构进行了研究。结果显示大部分成都粘土的石英颗粒粒度频率曲线与川西黄土、北部黄土相似，为单峰分布，但有些成都粘土样品表现为双峰分布。成都粘土的石英粒度组成、粒度参数与川西黄土和北部黄土存在差异，成都粘土以粉砂粒级为主，有较好的分选。成都粘土的石英颗粒表面微结构与北部黄土存在差异，成都粘土石英颗粒表面的三角形撞击坑和碟形坑较深，轮廓线明显呈规则排列，表现出水下环境形成的特征。依据石英粒度分布和石英表面微结构特征，对成都粘土成因和物源进行了初步讨论。

英文摘要：

In the present study, we focus on the quartz grain-size distribution and the surface micro-structure of quartz grains in the Chengdu Clay, as well as in the adjacent loess from the western Sichuan Plateau, the loess from the Qinling Mountains and the loess from the Chinese Loess Plateau. The results indicate that the quartz grains show unimodal distribution patterns in the most of Chcngdu Clay, as well as in the adjacent loess from the western Si- chuan Plateau, the loess from the Qinling Mountains and the loess from the Chinese Loess Plateau, but the quartz grains show bimodal distribution patterns in some of Chengdu Clay. The composition of quartz grain sizes and grain- size parameters in the Chengdu Clay are differerit with the loess from the western Sichuan Plateau and the loess from the Qinling Mountains and the loess from the Chinese I~ess Plateau. The Chengdu Clay mainly consists of silty quartz grains with well sorting. The quartz micro-structures of the Chengdu Clay and the loess from the Qinling Mountains and the loess from the Chinese Loess Plateau are different with each other. The surface of quartz grains in Chengdu Clay has deep dish and triangular pits. All of above suggest that the surface features of quartz grains in Chengdu Clay are formed in underwater. Base on the quartz grain-size distribution and quartz micro-structure, the origin of the Chengdu Clay was discussed.