The provenance of Taklamakan desert sand
The provenance of Taklamakan desert sand
复制标题
DOI：
10.1016/j.epsl.2015.12.036
复制
发表时间：
2016-03
影响因子：
5.3
通讯作者：
M. Rittner;P. Vermeesch;A. Carter;A. Bird;T. Stevens;E. Garzanti;S. Andó;G. Vezzoli;R. Dutt;Zhiwei Xu;Huayu Lu
中科院分区：
文献类型：
--
作者：
M. Rittner;P. Vermeesch;A. Carter;A. Bird;T. Stevens;E. Garzanti;S. Andó;G. Vezzoli;R. Dutt;Zhiwei Xu;Huayu Lu
塔里木盆地（中国新疆维吾尔自治区）塔克拉玛干沙漠中的沙迁移受两种相互竞争的运输媒介控制：风和水，它们在完全相反的方向上工作。净风成输运是从东北向南的，而河流输运则是从南向北，然后在北方边缘由西向东，这是由于下伏地形逐渐向北倾斜。本文首次对塔克拉玛干沙漠沙的物源进行了全面的研究，旨在阐明这两种输送机制的相互作用及其在沙海形成中的作用，并考虑塔里木盆地作为黄土高原（CLP）贡献源的潜力。我们的数据集包括39个风成和河流样品，其特点是碎屑锆石U-Pb年代学，重矿物，和散装岩相分析。虽然所有三个数据集的样本间的差异是微妙的，多元统计分析使用多维尺度（MDS）清楚地表明，塔里木沙漠砂是最相似的组成，从昆仑山（南）和帕米尔高原（西）的河流排水，并明显不同于天山（北）的沉积物来源。准噶尔盆地（天山以北）的一小部分样品产生不同的碎屑成分和年龄谱比任何地方在塔里木盆地，表明风成沉积物交换之间的两个盆地是最小的。虽然河流输沙主导了向塔里木盆地的输送，但风对中央沙海的沉积物进行了再活化和改造。主要河流的特征标志可以从入盆口一直追踪到塔里木河的终点，从南到北穿越沙漠的河流可以季节性地通过沙海绕过沉积物。来自昆仑山的较小的短暂河流在沙漠中结束，并在那里排放泥沙。河流径流和风力强度都具有很强的季节性，它们各自的输送强度和相反的方向维持着塔克拉玛干的位置和地形。
Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U–Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run-off and wind intensity are strongly seasonal, their respective transport strength and opposing directions maintain the Taklamakan in its position and topography.