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| 库姆塔格沙漠地表物质组成、来源和风化过程(英文) | |
| 引用本文： | 徐志伟,鹿化煜,赵存法,王先彦,苏志珠,王振亭,刘宏宜,王立新,卢琦.库姆塔格沙漠地表物质组成、来源和风化过程(英文)[J].地理学报(英文版),2011,21(6):1062-1076. |
| 作者姓名： | 徐志伟 鹿化煜 赵存法 王先彦 苏志珠 王振亭 刘宏宜 王立新 卢琦 |
| 作者单位： | School of Geographic and Oceanographic Sciences;the MOE Key Laboratory of Coast and Island Development;Nanjing University;Institute of Desertification Studies;Chinese Academy of Forestry;College of Earth and Environmental Sciences;Lanzhou University;Lanzhou Institute of Arid Meteorology;China Meteorological Administration; |
| 基金项目： | The Global Change Program of China, No.2010CB950203; China National S&T Basic Work Program,No.2006FY110800; Natural Science Foundation of China, No.40930103, 41021002 |
| 摘 要： | Kumtagh Desert is one of the eight biggest deserts in China, but poorly investigated before our interdisciplinary study because of the difficulty of access. In this paper, 33 representative surface sediment samples were collected from the Kumtagh Desert and analyzed in the laboratory to obtain heavy mineral components and geochemical element contents. Results show that various kinds of heavy minerals are present in these samples, with high levels of epidote and hornblende. Si and Al take up a large part of chemical composition. Compared with the average composition of geochemical elements of the upper continental crust (UCC), except Si and Ca, all elements are depleted to a certain degree; Fe, Mg, Ca, P, Ti and Mn have high correlation coefficients in their contents. The mineral and geochemical composition of the Kumtagh Desert sediments have a similarity with that of rocks of Altyn Tagh Mountains, and the surface sediments of the alluvial/diluvial fans around the Altyn Tagh Mountains and that of the Taklamakan Desert, indicating that one major source of the Kumtagh Desert sediments is located in the Altyn Tagh Mountains. Alluvial deposits and lake sediments in Aqik valley and lower reaches of Shule River are prone to be eroded and transported by the strong northeasterly wind into the Kumtagh Desert, forming another source of the desert deposits. An A-CN-K ternary diagram shows that a weak degree chemical weathering by the loss of Na and K occurred in these sediments, whereas A-CNK-FM ternary diagram suggests that Fe and Mg have undergone a significant chemical differentiation. Physical weathering processes cause easy erosion and enrichment in fine particles for mafic minerals, thus coarse desert sand particles can be relatively depleted in Fe and Mg. The mineral and geochemical composition of sediments in arid regions experiencing less chemical weathering are mostly affected by physical weathering. |
| 关 键 词： | minerals geochemical elements sediment provenance weathering process Kumtagh Desert |
| 收稿时间： | 29 October 2008 |
Composition,origin and weathering process of surface sediment in Kumtagh Desert,Northwest China |
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| Zhiwei?Xu,Huayu?Lu,Cunfa?Zhao,Xianyan?Wang,Zhizhu?Su,Zhenting?Wang,Hongyi?Liu,Lixin?Wang,Qi?Lu.Composition,origin and weathering process of surface sediment in Kumtagh Desert,Northwest China[J].Journal of Geographical Sciences,2011,21(6):1062-1076. | |
| Authors: | Zhiwei Xu Huayu Lu Cunfa Zhao Xianyan Wang Zhizhu Su Zhenting Wang Hongyi Liu Lixin Wang Qi Lu |
| Institution: | 1. School of Geographic and Oceanographic Sciences, the MOE Key Laboratory of Coast and Island Development, Nanjing University, Nanjing 210093, China 2. Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China 3. College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China 4. Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, China |
| Abstract: | Kumtagh Desert is one of the eight biggest deserts in China, but poorly investigated before our interdisciplinary study because of the difficulty of access. In this paper, 33 representative surface sediment samples were collected from the Kumtagh Desert and analyzed in the laboratory to obtain heavy mineral components and geochemical element contents. Results show that various kinds of heavy minerals are present in these samples, with high levels of epidote and hornblende. Si and Al take up a large part of chemical composition. Compared with the average composition of geochemical elements of the upper continental crust (UCC), except Si and Ca, all elements are depleted to a certain degree; Fe, Mg, Ca, P, Ti and Mn have high correlation coefficients in their contents. The mineral and geochemical composition of the Kumtagh Desert sediments have a similarity with that of rocks of Altyn Tagh Mountains, and the surface sediments of the alluvial/diluvial fans around the Altyn Tagh Mountains and that of the Taklamakan Desert, indicating that one major source of the Kumtagh Desert sediments is located in the Altyn Tagh Mountains. Alluvial deposits and lake sediments in Aqik valley and lower reaches of Shule River are prone to be eroded and transported by the strong northeasterly wind into the Kumtagh Desert, forming another source of the desert deposits. An A-CN-K ternary diagram shows that a weak degree chemical weathering by the loss of Na and K occurred in these sediments, whereas A-CNK-FM ternary diagram suggests that Fe and Mg have undergone a significant chemical differentiation. Physical weathering processes cause easy erosion and enrichment in fine particles for mafic minerals, thus coarse desert sand particles can be relatively depleted in Fe and Mg. The mineral and geochemical composition of sediments in arid regions experiencing less chemical weathering are mostly affected by physical weathering. |
| Keywords: | minerals geochemical dements sediment provenance weathering process Kumtagh Desert |
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