长江口水下三角洲沉积物粒度组成及其在减沙背景下的响应
Grain size of recent sediments in Yangtze River subaqueous delta and its response to sediments supply decline
-
摘要: 近年来长江口水下三角洲对入海泥沙减少的响应问题越来越受到关注。通过分析长江水下三角洲百年沉积速率的分布特征及位于水下三角洲泥质沉积区不同位置4个浅孔的粒度、210Pb和137Cs数据，探讨其对流域入海水沙变化及水动力变化的响应。研究结果显示，1954年后长江口北支萎缩是导致CDZS10孔所在区域沉积物粒度较其他3孔明显粗的主要原因。而CDZS10孔沉积物上粗下细则是由20世纪80年代三峡蓄水后长江入海泥沙显著下降、海洋动力明显增强引起的。另外，北支萎缩及三峡水库调蓄作用导致泥质区南移,并向杭州湾和嵊泗列岛延伸发展。Abstract: The response of Yangtze River subaquatic delta to river sediment decline has attracted more and more attention in recent years. In this paper, grain sizes and radiometric 210Pb and 137Cs of the cores in different areas of the subaquatic delta were analyzed to explore the response to river sediment decline and change of hydrodynamic force. The results show that grain sizes of core CDZS10 sediments are much coarser than those of the other three cores which might be closely related to the block of north branch of Yangtze River in the estuary after 1954. In terms of sediment composition the authors found grain size coarsening up from 1.2m (1979) in Core CDZS10 which might be an obvious response to significant sediments supply decline of the Yangtze River after the 1980's. In addition, the block of north branch and impoundment hasled to the mud region moving southward and extending to Hangzhou Bay and Shengsi Islands.
-
Key words:
- grain size /
- sediment decline /
- north branch /
- response /
- marine dynamics
-
-
[1] 水利部长江水利委员会. 长江泥沙公报[M]. 武汉:长江出版社, 2012.
[2] Yang S, Milliman J, Li P, et al. 50000 dams later:erosion of the Yangtze River and its delta[J]. Global and Planetary Change, 2011, 75(1):14-20.
[3] Luo X, Yang S, Zhang J. The impact of the Three Gorges Dam on the downstream distribution and texture of sediments along the mid-dle and lower Yangtze River (Changjiang) and its estuary, and subse-quent sediment dispersal in the East China Sea[J]. Geomorphology, 2012, 179:126-140.
[4] 秦蕴珊, 赵一阳, 陈丽蓉, 等. 东海地质[M]. 北京:科学出版社, 1987:290.
[5] 王昕, 石学法, 王国庆, 等. 长江口及邻近海域现代沉积速率及其对长江入海泥沙去向的指示意义[J]. 地球科学——中国地质大学学报, 2013, 38:763-775.
[6] 胡方西, 胡辉, 谷国传, 等. 长江口锋面研究[M]. 上海:华东师范大学出版社, 2002.
[7] 庄克琳. 长江水下三角洲的沉积特征[D]. 中国海洋大学博士学位论文, 2005.
[8] 王永红. 长江河口涨潮槽的形成机理与动力沉积特征[M].上海:华东师范大学, 2003.
[9] 段凌云, 王张华, 李茂田, 等. 长江口沉积物210Pb分布及沉积环境解释[J]. 沉积学报, 2005, 23(3):514-522.
[10] 夏小明, 杨辉, 李炎, 等. 长江口-杭州湾毗连海区的现代沉积速率[J]. 沉积学报, 2004, 22(1):130-135.
[11] DeMaster D J, McKee B A, Nittrouer C A, et al. Rates of Sediment accumulation and particle reworking based on radiochemical mea-surements from continental shelf deposits in the East China Sea[J]. Continental Shelf Research, 1985, 4:143-158.
[12] 刘升发, 石学法, 刘焱光, 等. 东海内陆架泥质区沉积速率[J]. 海洋地质与第四纪地质, 2009, 29(6):1-7.
[13] 杨作升, 陈晓辉. 百年来长江口泥质区高分辨率沉积粒度变化及影响因素探讨[J]. 第四纪研究, 2007, 27:690-699.
[14] 冯旭文, 金翔龙, 章伟艳, 等. 长江口外缺氧区柱样沉积物元素的分布及其百年沉积环境效应[J]. 海洋地质与第四纪地质, 2009, 29(2):25-31.
[15] 张瑞, 潘少明, 汪亚平, 等. 长江河口水下三角洲210Pb分布特征及其沉积速率[J]. 沉积学报,2009, 27(4):704-713.
[16] 沈焕庭. 长江河口物质通量[M]. 北京:海洋出版社, 2001:176.
[17] 恽才兴. 图说长江河口演变[M]. 北京:海洋出版社, 2010:260.
[18] 段凌云. 长江口外春季盐度锋锋面不规则流现象及其意义探讨[D]. 华东师范大学硕士学位论文, 2006.
[19] Luo X, Yang S, Zhang J. The impact of the Three Gorges Dam on the downstream distribution and texture of sediments along the middle and lower Yangtze River (Changjiang) and its estuary, and subsequent sediment dispersal in the East China Sea[J]. Geomor-phology, 2012, 179:126-140.
-
计量
- 文章访问数: 916
- PDF下载数: 77
- 施引文献: 0
下载: