澄湖SC7孔沉积物粘土矿物特征及其古地理意义
- 华东师范大学资源与环境科学学院地理系上海200062
- 收稿日期:
1900-01-01
- 修回日期:
1900-01-01
- 刊出日期:
2010-04-10
摘要: 苏州澄湖湖底残留有一条NNW—SSE延伸且已被淤平的古河道。通过对湖心区古河道段SC7孔沉积物的粘土矿物XRD分析及与湖底硬粘土（Q3）、湖岸区沉积（Q4）和长江口滩地现代沉积的比较，表明古河道充填沉积中的粘土矿物主要为伊利石，其次为高岭石、绿泥石、蛭石，还有少量蒙皂石及蛭石/绿泥石混层矿物；其中的伊利石和绿泥石含量均明显偏高，高岭石含量则偏低，伊利石结晶度也较高。粘土矿物组合兼具太湖流域地带性粘土矿物和长江口沉积物的特点，表明古河道充填沉积既有来自本流域表层物质和澄湖扩大过程中的湖岸崩积，也受到长江物源的影响。这一沉积过程也说明古河道在最大海侵时涨潮流和洪水引起海水和江水的频繁倒灌，直至淤塞和淹废。
Clay Mineral Characteristics of SC7 Core Sediments from Chenghu Lake (Suzhou) and Their Paleogeographic Significance
- Department of Geography, School of Resources and Environmental Sciences, East China Normal University, Shanghai 200062
- Received Date:
1900-01-01
- Rev Recd Date:
1900-01-01
- Publish Date:
2010-04-10
Abstract: Chenghu, a mediumsize and shallow lake, is situated in the central Taihu Plain of Lower Changjiang River, China. In its northcentral part, a temporal water pumped area from 2003~2007, there have developed a NNWSSE paleochannel filled up with deposits on the flat bottom. Sediment core (SC7) from this paleochannel near the central part of the lake was taken and the clay minerals were studied through Xray diffraction. Studies show that the main clay minerals, calculated by comparing major peak heights, are illite (70.0%~72.4%), kaolinite (10.0%~11.6%), 1.4 nm minerals (12.8%~14.6%), and small amounts of smectite (<5%). Compared with the bottom material ( hard clay') and lakeshore sediments, the sediments are characterized by higher content of illite, chlorite and better illite crystallinity, but lower content of kaolinite. These characteristics of clay minerals indicate that the sediments may come from both the lake catchment and the Changjiang River, and that the paleochannel (the ancient Dongjiang River) must have experienced frequent tidal upstream flow or Changjiang River's floods after entering the MidHolocene. As the Dongjiang River was filled up, the coastal development stage of Chenghu area ended.
师育新. 澄湖SC7孔沉积物粘土矿物特征及其古地理意义[J]. 沉积学报, 2010, 28(2): 339-345.
| 引用本文: |
师育新. 澄湖SC7孔沉积物粘土矿物特征及其古地理意义[J]. 沉积学报, 2010, 28(2): 339-345.
|
SHI Yuxin. Clay Mineral Characteristics of SC7 Core Sediments from Chenghu Lake (Suzhou) and Their Paleogeographic Significance[J]. Acta Sedimentologica Sinica, 2010, 28(2): 339-345.
| Citation: |
SHI Yuxin. Clay Mineral Characteristics of SC7 Core Sediments from Chenghu Lake (Suzhou) and Their Paleogeographic Significance[J]. Acta Sedimentologica Sinica, 2010, 28(2): 339-345.
|
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