腾格里沙漠表沙常量元素地球化学特征及其空间分布  

Geochemical element characteristics and spatial distribution of surface sand major elements in the Tengger Desert

作　　者：马立 杨静[1,2,3] 张峰 MA Li;YANG Jing;ZHANG Feng(College of Geography and Remote Sensing Science,Xinjiang University,Ürümqi 830046,China;Xinjiang Key Laboratory of Oasis Ecology,Urumqi 830046,China;Xinjiang Field Scientific Observation and Research Station for the Oasisization Process in the Hinterland of Taklamakan Desert,Yutian 848400,China)

机构地区：[1]新疆大学地理与遥感科学学院,乌鲁木齐830046 [2]新疆绿洲生态自治区重点实验室,乌鲁木齐830046 [3]塔克拉玛干沙漠腹地绿洲过程新疆野外科学观测研究站,于田848400

出　　处：《第四纪研究》2025年第1期91-104,共14页Quaternary Sciences

基　　金：国家科技基础资源调查专项项目(批准号:2017FY101004);国家自然科学基金项目-新疆联合基金项目本地优秀青年人才培养专项项目(批准号:U1503381)共同资助。

摘　　要：元素地球化学对沉积物的物源、搬运沉积过程、化学风化具有重要的指示意义。本研究通过采集腾格里沙漠不同区域沙丘顶部0~10 cm深度的43件表沙样品,进行常量元素地球化学测定,借助不同的化学风化指标及相关的统计学方法进行分析,对该沙漠的常量元素组成特征、空间分布规律及其影响因素进行初步的讨论。结果表明:1)腾格里沙漠表沙125~250μm粒级的常量元素以SiO_(2)为主,其次为Al_(2)O_(3),其余元素平均含量高低依次为Na_(2)O、 K_(2)O、 Fe_(2)O_(3)、 CaO、 MgO、 Ti和Mn,并且在UCC标准化中,所有样品的SiO_(2)均呈现富集状态,其余元素为亏损,CaO与Fe_(2)O_(3)、 MgO、 Ti、 Mn等亏损元素分异程度较高;2)A-CN-K图和CIA、 WIP等化学风化指标显示腾格里沙漠表沙处于化学风化初级阶段,Ca元素相对Na元素而言风化程度更高;A-CNK-FM图与相关性分析显示,沙漠表层沙矿物成分以石英、长石为主,MgO的含量应同时受到碳酸盐矿物和铁镁质矿物的影响;化学风化程度结果表明沙漠西南地区显著低于其他地区;3)物源、搬运沉积过程和化学风化是影响腾格里沙漠表沙常量元素产生差异的主要原因,除了沙漠周边山脉通过河流搬运迁移为沙漠提供新鲜物质外,巴丹吉林沙漠和腾格里沙漠内存在的湖相沉积物就地起沙也是沙漠表沙的物质来源之一,腾格里沙漠表沙存在沉积旋回现象,旧沉积物的再循环对沙漠表沙常量元素也存在影响。Elemental geochemistry has an important indicator significance for the source of sediment,transport and deposition process,and chemical weathering.In this study,43 dune sand samples from the top of dunes in different regions(37.51°~40.04°N,102.96°~105.57°E)of the Tengger Desert were collected for major element geochemical determination.Using different chemical weathering indicators and related statistical methods for analysis,a preliminary discussion is conducted on the composition characteristics,spatial distribution patterns,and influencing factors of the constant elements in the desert.The results show that:(1)The content of SiO2 in surface sand(125~250μm)of Tengger Desert is the highest among major elements,with the content range of 77.68%~81.98%,and the average content of 79.61%.Next is Al_(2)O_(3),with a content ranging from 8.36%to 9.55%,with an average content of 8.89%.The content of remaining elements is relatively low,and according to the average content of remaining elements,they are Na_(2)O,K_(2)O,Fe_(2)O_(3),CaO,MgO,Ti,and Mn in order.Except for SiO_(2),which is significantly enriched compared to UCC,all other elements show varying degrees of depletion compared to UCC.SiO_(2) and Al_(2)O_(3) have the lowest degree of differentiation compared to UCC,followed by Na_(2)O and K2O.Ti,Mn,Fe_(2)O_(3),and MgO have higher degrees of differentiation,while CaO has the highest degree of differentiation.(2)The Tengger Desert is in the primary stage of chemical weathering,and the ternary diagram shows that the leaching degree of Ca is stronger than that of Na;The spatial distribution of chemical weathering characteristics shows that the degree of chemical weathering near the Shiyang River basin in the west of the desert is significantly lower than that in other areas of the desert.On the whole,the degree of chemical weathering in the east of Tengger Desert is higher than that in the west;The A-CNK-FM diagram shows that the mineral composition of desert surface sand is mainly feldspar,and the influence of amph

关 键 词：腾格里沙漠 地球化学 常量元素 化学风化 

分 类 号：P597.3[天文地球—地球化学] P941.78[天文地球—地质学]