Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (11): 2105-2116.doi: 10.11821/dlxb201811005

• Climate Change and Earth Surface Processes • Previous Articles     Next Articles

The sediment sources and quantitative evaluation of tidal flat at Qidong foreland, the Yangtze Estuary in recent 100 years

ZHANG Yunfeng1(),ZHANG Zhenke2,REN Hang2,GAO Lei3,DING Haiyan1   

  1. 1. Research Institute of Jiangsu Coastal Development, Yancheng Teachers University, Yancheng 224007, Jiangsu, China
    2. School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
    3. Nanjing Institute of Geography & Limnology, CAS, Nanjing 210008, China;
  • Received:2017-12-08 Online:2018-11-25 Published:2018-11-22
  • Supported by:
    National Natural Science Foundation of China, No.41501003, No.41701101, No.41371024, No.41771199; Philosophy and Social Sciences Foundation of the Jiangsu Higher Education Institutions of China, No.2013SJD790028; Natural Science Foundation of the Jiangsu Higher Education Institutions of China, No.14KJD170005, No.14KJA170006; Natural Science Foundation of Jiangsu Province, China, No.BK20160446

Abstract:

The transport of sediment by rivers to the oceans plays an important role in coastal stabilization. The Qidong foreland is located on the junction between Yangtze Estuary and Jiangsu coast, where strong land-ocean interactions are highly sensitive to environmental changes. In order to examine sediment sources and change, QDZ-1 core sediments were collected at Qidong foreland tidal flat. And the content of micro-elements was analyzed by ICP-MS, further, the source-indicating significance of micro-elements was discussed based on distribution and enrichment coefficient. The result showed that sediment sources derive from the Yangtze River and the south Yellow Sea. In addition, sediment sources were quantitatively evaluated by estimation of sedimentary end-members. The result showed that sediment sources could be divided into three stages. The sediment flew mainly from the sediment transport of the Yangtze River into the sea, with the contribution rate being 68.1%. Then, the contribution rate gradually decreased with the decline of the North Branch, down to 38.5% during the period of 1930-1972, and to 17.5% after 1972. Meanwhile, the suspended sediments from southern Yellow Sea moved mainly to the south by strong tide and Subei coastal current, and the contribution rate was 27.1% before 1930. Subsequently, the contribution rate gradually increased, up to 55.6% during the period of 1930-1972, and to 75.9% after 1972. The sediment sources of Qidong foreland tide flat mainly transformed from the Yangtze sediment to the south Yellow Sea sediment. The changes in stages of sediment source were consistent with the decline of the North Branch.

Key words: Yangtze estuary, Qidong foreland tide flat, sediment sources, environmental significance, quantitative evaluation