| This paper taking the Nitraria nebkhas located in the southwestern margin of the Mu Us Sandy Land as research object, primarily analyzed the sediments characteristics of the vertical profile of the nebkhas, including size composition, organic matter content, element composition and chemical weathering intensity and the environmental implication. The main results are as follows:(1) The very fine sand and fine sand which can saltation are the most important and most stable composition of the nebkhas sediments; the similar degree of the size and element composition of the sediments between the nebkhas is higher than between the nebkha and the interdune due to the windy sorting action; The nebkhas sediments are mainly from the interdune, and the sediments content come from far source is less than 3%.(2) Compared with the interdune, the nebkhas sediments contain more fine sand and very fine sand which can saltation and modified saltation; in addition, the content of the organic matter and most elements of the nebkhas sediments are more lower, and the chemical weathering intensity is also weaker due to the influence of the size composition.(3) The organic matter of the nebkhas sediments are mainly from the interdune, and a few are from the self-feedback action of nebkhas vegetation; after the nebkhas formatted, the organic matter content of the interdune would certainly decrease, therefore, the appearance of the nebkhas could be used as indicator of land degradation.(4) Since the development of the nebkhas, the intensity of the wind-sand activity in Yanchi County of Ningxia Hui Autonomous Region shows a decreasing trend, which is consistent with in northern China, but in Dingbian County of Shanxi Province shows an increasing trend, which may be caused by human activities; overall, since the development of the nebkhas, the nebkhas’deposition process is simple in study area, deposition environment is relatively steady, and the sediments almost have never experienced chemical weathering. |
PDF Full Text Request