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Journal of Desert Research ›› 2022, Vol. 42 ›› Issue (5): 122-132.DOI: 10.7522/j.issn.1000-694X.2022.00030

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Grain size characteristics of sediments in sandy land around the Poyang Lake and its influencing factors

Wen Zhang1(), Dingding Du1(), Zhiwen Li1,2, Wangyang Wu1, Xiangjie Li1, Yonghui Bai1   

  1. 1.School of Earth Science,East China University of Technology,Nanchang 330013,China
    2.School of Environmental and Chemical Engineering,Foshan University,Foshan 528000,Guangdong,China
  • Received:2022-02-10 Revised:2022-03-31 Online:2022-09-20 Published:2022-09-22
  • Contact: Dingding Du

Abstract:

The sandy land around the Poyang Lake is a typical sandy land in subtropical humid region. The problem of land desertification is serious, and has always been a research hotspot. However, there is little significance for the study of sandy land around the Poyang Lake because it is concentrated in a small area. Hence, it is extremely important to study the grain size comparison based onf a lot of sampling points around the Poyang Lake. In this paper, 57 sand samples were selected from Lushan City, Duchang County, Yongxiu County and Xinjian District, etc, and their grain size characteristics were analyzed. The results showed that: (1) The sandy land around the Poyang Lake is mainly composed of medium sand, fine sand and coarse sand, and the content of the three sand is more than 90%.The mean value of Mz is 1.79 Φ, and the sorting is poor with positive deviation and sharp distribution. (2) The grain size characteristics of sediment surface layer and 20-40cm depth were different in different sandy land types around the Poyang Lake. The surface layer of fixed dune, semifixed dune, active sand dune, wetland grass beach and benchland were coarser grain size than those of 20-40 cm depth, but the surface layers of active sand dune and wetland grass beach were better sorting than those of 20-40 cm depth. The dominant grain size content and grain size parameters of wetland grass beach and benchland are different from those of dune. (3) The fixed dune, semifixed dune and active sand dune are eolian deposits around the Poyang Lake. The benchland is dominated by fluvial action and supplemented by wind erosion.The wetland grass beach is formed under the combined wind force and hydrodynamic force. The SdSK and Kg of sandy land decreased from south to north along the prevailing wind direction. The aeolian sand movement of the Poyang Lake is mainly two jumps and one suspension style, and the main source of aeolian sand is on the spot, supplemented by river beach and lake beach.

Key words: sandy land, particle size, influencing factors, Poyang Lake

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