| 准噶尔盆地表层沉积物的稀土元素特征与物源指示 |
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| 引用本文： | 黄雨振, 陈秀玲, 程良清, 管清玉, 肖鑫豪, 卢欣. 准噶尔盆地表层沉积物的稀土元素特征与物源指示[J]. 第四纪研究, 2018, 38(6): 1325-1335. doi: 10.11928/j.issn.1001-7410.2018.06.01 |
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| 作者姓名： | 黄雨振 陈秀玲 程良清 管清玉 肖鑫豪 卢欣 |
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| 作者单位： | 1. 福建师范大学地理研究所, 福建 福州 350007; 2. 福建师范大学湿润亚热带山地生态国家重点实验室培育基地, 福建 福州 350007; 3. 中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室, 陕西 西安 710061; 4. 兰州大学资源环境学院, 西部环境教育部重点实验室, 甘肃 兰州 730000 |
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| 基金项目： | 国家自然科学基金项目（批准号：41302149、41572162和U1405231）、福建师范大学创新团队项目（批准号：IRTL1705）和福建省公益类科研院所基本科研专项项目（批准号：2014R1034-2）共同资助 |
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| 摘 要： | 准噶尔盆地的新生代沉积的物质来源对认识中亚地区乃至全球气候环境演变、亚洲内陆干旱化以及粉尘输送路径等关键科学问题都具有重要的意义，但目前对盆地内沉积物的物质来源的研究还比较粗略。文章以准噶尔盆地内不同类型的表层沉积物为研究对象，通过对稀土元素特征的研究进一步探讨盆地内不同沉积的物质来源与相互联系。研究结果表明：准噶尔盆地不同区域表层沉积物的稀土元素含量（不含Y元素）变化较大，变化范围为55.54~194.44 μg/g；大部分样品的δCe值在0.95~1.05之间，未见明显的Ce异常，指示了盆地内整体干旱环境下较弱的风化成壤作用，而Eu异常和UCC标准化配分模式表现出的复杂变化，可能指示了准噶尔盆地表层沉积物物质来源的多源性。根据盆地内表层沉积物的稀土元素总量、配分模式以及δEu值表现出的不同特征，结合了盆地内的区域地形和盛行风向等要素，认为盆地东部的戈壁砂和周围山地的基岩碎屑物之间存在着一定的物源继承，同时强劲的西北风也为该地带来了来自盆地北部和中部的物质来源；北部的阿尔泰山碎屑物质是盆地北部戈壁砂和沙漠砂的主要物质来源，但戈壁砂表现出的Eu中度亏损和较高的ΣREE值可能代表着该区域还存在更为广阔的物源；盆地西部各类沉积物之间表现出的稀土元素特征的相似性表明该地缺乏外界物质的参与，物源具有明显的局域性；盆地南缘的沙漠砂和河流表层沉积物主要来源于天山碎屑物质经冰川磨蚀及寒冻风化等作用形成的粉砂粒级物质，但是该地的黄土在地形和风向的影响下表现出了复杂的物质来源，盆地中的沙漠、天山碎屑物质、盆地东部的戈壁砂，甚至于中亚广大荒漠区的粉尘都为黄土提供了部分物源。
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| 关 键 词： | 表层沉积物 稀土元素 物质来源 准噶尔盆地 |
| 收稿时间： | 2018-05-12 |
| 修稿时间： | 2018-08-01 |
REE characteristics and its provenance implication of surface sediments in the Junggar Basin |
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| Huang Yuzhen, Chen Xiuling, Cheng Liangqing, Guan Qingyu, Xiao Xinhao, Lu Xin. REE characteristics and its provenance implication of surface sediments in the Junggar Basin[J]. Quaternary Sciences, 2018, 38(6): 1325-1335. doi: 10.11928/j.issn.1001-7410.2018.06.01 |
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| Authors: | Huang Yuzhen Chen Xiuling Cheng Liangqing Guan Qingyu Xiao Xinhao Lu Xin |
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| Affiliation: | 1. Institute of Geography, Fujian Normal University, Fuzhou 350007, Fujian; 2. State Kay Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University, Fuzhou 350007, Fujian; 3. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi; 4. Laboratory of Western China's Environmental System(Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu |
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| Abstract: | The Junggar inland basin is located in Northwestern China, a geographical center of the Asian interior. The widespread Cenozoic deposits contain valuable archives about the aridification of inland Asia, the dust transportation pathways and the evolution of global climate change. They also can contribute to the debates about the effects of the uplifted Tibetan Plateau and the regression of the Tethys Ocean on the atmospheric circulation in Central Asia. The provenance of eolian sediments is fundamental for understanding its origin, transportation and climatic significance. Inspite of the progress on the provenance of the surface sediments in the Junggar Basin, the source of these sediments are still insufficiently studied and remain controversial. More detailed research with more proxies is needed. Rare Earth Elements (REE) has been widely used as trace elements in provenance studies of various sediments because of the similar chemical properties and little change during weathering, transportation and diagenesis. In this paper, through field investigation in the Junggar Basin, combined with its topography, wind direction circulation and so on, 48 samples of various surface sediments and bedrocks were collected from different regions of the Junggar Basin. Among them, 35 samples were surface sediments, including loess, desert sands, Gobi sands, surface soils, surface sediments from the rivers, and 13 bedrock samples. REE analyses have been taken out to further explore the material sources and interrelations of the different sediments in the basin. The result shows that the total concentrations of rare earth elements excluding Y (ΣREE) in the samples of different regions in the Junggar Basin are significantly different and the ΣREE values vary from 55.54 μg/g to 194.44 μg/g. δEu values and UCC-normalized REE distribution patterns of the samples from different locations, as well as REE concentrations, differ from each other. These REE characteristics may suggest that the sources of the sediments in the Junggar Basin are diverse. δCe values of the most samples from 0.95 to 1.05 and there are hardly any Ce anomalies in the samples of the basin, which reflect an overall arid climate leading to weak pedogenesis. REE characteristics, such as ΣREE, the UCC-normalized REE distribution patterns, and the δEu values, integrated with knowledge of relevant topography and wind patterns present that there is a source succession between Gobi sands in the eastern basin and the debris derived from surrounding mountains. The dust entrained by the strong northwest wind from the northern and central basin has also important contributions to the sources. REE characteristics of the Gobi sands and the desert sands in the northern basin reveal that the silt production from the Altai Mountains are their major sources, however, the moderately negative anomaly and higher ΣREE values may represent a broader source of Gobi sands in this area. The similarity of the REE characteristics among various sediments in the western basin indicates that there is regional material source with little foreign material. For the southern basin, silt production from the Tianshan Mountains by frost weathering and/or glacial grinding should be the major sources of the desert sands and surface sediments from the rivers. The loess covering on the northern slope of the Tianshan Mountains is multi-sourced due to the influence of topography and wind direction. It derives from the desert in the basin, debris from the Tianshan Mountains, and the Gobi sands in the eastern basin. The dust from Central Asia transported by westerly winds may have also made a contribution to the material sources. |
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| Keywords: | surface sediments REE provenance the Junggar Basin |
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