苏州澄湖湖底硬粘土粒度特征及成因初探  

The Particle Size Characteristics and Origin of Hard Clay in the Central Area of Chenghu Lake,Jiangsu Province,China

作　　者：付苗苗[1] 戴雪荣[1] 师育新[1] 郑祥民[1] 

机构地区：[1]华东师范大学资源与环境科学学院地理系,上海200062

出　　处：《沉积学报》2008年第5期828-832,共5页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(批准号:40571170)资助

摘　　要：澄湖是太湖平原上的一个浅水湖泊,湖底十分平坦,主要由硬粘土组成,同时发育有NW—SE横穿澄湖的古河道和泥沼洼地。在接近湖泊中心部位的古河道中打钻获得了4m长的岩芯,并进行了详细的粒度分析。结果表明,该岩芯下部的硬粘土主要由细粉砂、中粉砂和粘土组成,分别占26.7%～38.1%,26.9%～34.3%和19.7%～26.2%,可命名为粘土质粉砂;众数粒径为10～50μm,平均占57.9%;平均粒径为6.3～6.9。将其与上部的湖泊沉积、镇江下蜀黄土和中国北方各地黄土的粒度比较表明,苏州澄湖湖底的硬粘土原本也是风尘沉积。Chenghu is one of the shallow lakes in Taihu Plain, Jiangsu Province, China. The bottom of Chenghu is extremely flat, which is mainly composed of ‘ hard clay＇ （ a kind of sediment consisting of silt and clay）, and has been featured with a NW-SE paleo-channel in the middle and shallow swamps in the middle-west. Sediment record in these paleo-channel and swamps may become good archives, spanning from the Last Glacial to the Post-glacial. This paper focuses on the hard clay of the lake bottom based on the study of the SC7 core （about 4 meters long） that drilled in the paleo-channel at the bottom of the lake. The composition of the particle-size of the hard clay is discussed in detail. The hard clay in Chenghu mainly consists of fine silt, medium silt and clay; the content of fine silt from 26.7% to 38.1%, that of medium silt from 26.9% to 34.3%, that of clay from 19.7% to 26.2%, which belongs to clayey silt. The 10-50 μm particle group is the ＂dominate group＂ of the hard clay in Chenghu with the average content of 57.9%. The mean particle-size is from 6.3qb to 6.9Ф. Through the comparison of the particle-size characteristics among the hard clay in Chenghu, lake sediments, Xiashu Loess in Zhenjiang of Jiangsu Province and the northern China loesses in Qaidam, western Gansu, eastern Gansu, northern Shaanxi, western Shanxi and Shandong Province, we tend to conclude that the hard clay in Chenghu is of aeolian origin.

关 键 词：澄湖 硬粘土 粒度 太湖平原 长江 

分 类 号：P512.2[天文地球—地质学]