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| Mineral Composition of Sand Particles of Modern Mobile Sand Dunes in the Mu Us Sandy Land |
| Hu Guanguan1, Li Baosheng1,2, Wen Xiaohao1, Niu Dongfeng1, Guo Yihua1, Guo Yuanjun1, Si Yuejun1, Shu Peixian1 |
1. School of Geography, South China Normal University, Guangzhou 510631, China;
2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China |
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Abstract Mineral composition of 16 modern mobile sand dunes sand particle samples from Mu Us Sandy Land was analyzed. Results show that: (1) Light minerals dominate in content, with 94.8% on average and the principal compositions are quartz and feldspar; In these samples little heavy minerals exist, with average 1.6%, but number of mineral species is various, with about 22 kinds. (2) More than 2/3 of heavy minerals are silicate minerals, and the TOP 3 are amphibole, epidote and garnet in content. (3) Unstable minerals and relatively stable minerals account for a big proportion in heavy minerals. In this two kinds of mineral assemblages, silicate minerals occupy absolute advantage, respectively 100% and 98.75%. (4) Hard minerals and ultrahard minerals in heavy minerals totally reach up to 80.17%, respectively 61.57% and 18.60%. The results also show high Q/TF ratio (average 6.10) in light minerals and high HW value (average 3.89) in heavy minerals. Rock-forming minerals (average 26.7%) account for nearly 1/3 in heavy minerals. Therefore, given the high content of hard and ultrahard heavy minerals, all these indicate that the dune sand particles was deposited in the dry-cold climate with strong wind-sand flow environment and weak biological and chemical weathering. The discussion of this paper on mineral components of sans particles of modern mobile sand dunes in Mu Us Sandy Land not only proves the essential relationship between the arid climate and the high content of unstable minerals and relatively stable minerals, but also shows the existence of various kinds and high content of hard and ultrahard minerals greatly inhibits both physical weathering and biochemical weathering and makes it difficult to reverse to pedogenesis fundamentally. Even though the dunes can be fixed, it is still difficult to eliminate the objective existence of potential desertification because of such mineral components of the dunes, so the degeneration of ecological environment resulted from desertification has essential relationship with the physical properties of clastic minerals in dune sand. Therefore, the dry-cold and windy climate conditions and its resulted special material composition in dune sand are the two essential causes of land desertification.
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Received: 20 November 2013
Published: 20 November 2014
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Corresponding Authors:
李保生(Email:libsh@scnu.edu.cn)
E-mail: libsh@scnu.edu.cn
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2014, Vol. 34 
