Knowledge Resource Center for Ecological Environment in Arid Area
| 巴丹吉林沙漠石英delta~(18)O值及其物源意义 | |
| 其他题名 | Characteristics of Oxygen Isotopic Compositions of Quartz in the Badain Jaran Desert and Its Implications for Sand Provenances |
| 付旭东 | |
| 来源期刊 | 沉积学报
 |
| ISSN | 1000-0550 |
| 出版年 | 2017 |
| 卷号 | 35期号:1页码:67-74 |
| 中文摘要 | 巴丹吉林沙漠是世界上沙丘最高大的沙漠,其沙源研究对认识沙漠形成、高大沙山发育和防沙治沙工程有重要意义。石英是沙漠沉积物中常见的矿物,其氧同位素值可示踪物源。采集沙漠西北部、东部、东南部高大沙山、丘间低地与湖泊以及雅布赖山前的表层沉积物,测定了样品不同粒级的石英delta~(18)O值。结果表明:①石英delta~(18)O值随粒级减小有增大趋势,同一样品不同粒级石英delta~(18)O值存在较大差异,相同粒级石英delta~(18)O值也有变化。②石英delta~(18)O值介于9.4~19.3,均值为13.3(n=55);其中沙丘沙的石英delta~(18)O值介于9.5~16.6,均值为12.9 (n=39);湖相沉积物的石英delta~(18)O值介于9.4~19.3,均值为14.2(n=16)。③区域内,<16 mum粒级的石英delta~(18)O值与16~64 mum、125~154 mum、200~250 mum、> 300 mum粒级的石英delta~(18)O值都存在显著差异,但200~250 mum与 > 300 mum粒级的石英delta~(18)O值没有显著差异;经区域对比,巴丹吉林沙漠 < 16 mum粒级的石英delta~(18)O值与柴达木盆地沙漠、蒙古戈壁风成沉积物 < 16 mum石英delta~(18)O值无显著差异,但巴丹吉林沙漠16~64 mum粒级的石英delta~(18)O值与蒙古戈壁风成沉积物16~64 mum石英delta~(18)O值存在显著差异;这似乎暗示研究区的细颗粒物质可能是远源的。巴丹吉林沙漠沉积物的石英delta~(18)O值位于火成岩石英、砂岩和变质岩石英delta~(18)O值分布阈值内,受区域地质条件、物源混合、粒级效应等因素的影响,砂粒级的石英delta~(18)O值所指示的母岩成份特征与祁连山区岩石的岩性有较好吻合。 |
| 英文摘要 | Badain Jaran Desert is the second largest area of shifting sands in China and features the tallest dunes on Earth. Identifying provenance of aeolian deposits in the Badain Jaran Desert is critical to understand the formation and development of mega-dunes. Quartz is the most common mineral of Chinese desert sediments, and oxygen isotopic composition of quartz has been regarded as a useful tracer of provenance. Oxygen isotopic compositions were measured by isotopic techniques in various size fractions of quartz, which were extracted from aeolian and lacustrine sediments collected on northwestern, eastern, and southeastern part in the Badain Jaran Desert. The results indicate that the delta~(18)O values increase with decreasing grain size in quartz from aeolian and lacustrine sediments, and the delta~(18)O composition of quartz in various size fractions has notable variations ranging from 3.1 to 9.9. The delta~(18)O values in quartz in all size fractions are between 9.4 and 19.3, in which aeolian sands range from 9.5 to 16.6, and lacustrine sediments vary from 9.4 to 19.3. In the study area, the delta~(18)O values of fine-grained (<16 mum) quartz show significant differences between different size fractions of the grains (i.e., 16~64 mum,125~154 mum, 200~250 mum, >300 mum), whereas two coarser fractions (200~250 mum and >300 mum) exhibit no significantly different in the delta~(18)O values. Furthermore, when isotopic results are compared with available findings at regional scale, the delta~(18)O values of fine-grained (<16 mum) quartz have no significant difference between Badain Jaran Desert, Qaidam Basin Desert, and Mongolian Gobi Desert, but that of silt-grained (16~64 mum) quartz exist notable difference between the Badain Jaran Desert and Mongolian Gobi Desert. From these observations, it appears likely that the fine-grained components in each sample probably have a more distal origin. A large range of delta~(18)O values, from 9.4 to 19.3 is present within the aeolian dune and lacustrine sediments, fall within the range of values considered to be indicative of igneous, metamorphic, and sedimentary rocks. The variable delta~(18)O values seem to result from the mixing ratio of igneous, sedimentary and metamorphic rocks. These differences in delta~(18)O values can be related to regional geological setting, mixing ratio of various detrital components, and grain size dependence so on. In the dominant size fraction (125~154 mum, 200~250 mum) of sediments in Badain Jaran Desert, delta~(18)O values are mostly between 11.0 and 14.9, but extend down to 9.4. It suggests that quartz detritus is mostly derived from sedimentary and metamorphic rocks, which is considered as mostly originating from Qilian Shan mountainous areas although the local source cannot be ruled out. |
| 中文关键词 | 巴丹吉林沙漠 ; 沙源 ; 石英 ; 氧同位素 |
| 英文关键词 | Badain Jaran Desert sand provenance Quartz oxygen isotopic compositions |
| 语种 | 中文 |
| 国家 | 中国 |
| 收录类别 | CSCD |
| WOS类目 | GEOSCIENCES MULTIDISCIPLINARY |
| WOS研究方向 | Geology |
| CSCD记录号 | CSCD:5928185 |
| 资源类型 | 期刊论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/235720 |
| 作者单位 | 河南大学环境与规划学院, 开封, 河南 475004, 中国 |
| 推荐引用方式 GB/T 7714 | 付旭东. 巴丹吉林沙漠石英delta~(18)O值及其物源意义[J],2017,35(1):67-74. |
| APA | 付旭东.(2017).巴丹吉林沙漠石英delta~(18)O值及其物源意义.沉积学报,35(1),67-74. |
| MLA | 付旭东."巴丹吉林沙漠石英delta~(18)O值及其物源意义".沉积学报 35.1(2017):67-74. |
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