Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau
Najorka, J (Najorka, Jens)[2]; Sinha, R (Sinha, Rajiv)[5]; Gupta, S (Gupta, Sanjeev)[1]; Tada, R (Tada, Ryuji)[4]; Sun, YB (Sun, Youbin)[3]; Chen, HY (Chen, Hongyun)[3]; Dong, SF (Dong, Shuofei)[1]; Strekopytov, S (Strekopytov, Stanislav)[2]; Weiss, DJ (Weiss, Dominik J.)[1,2]; Ferrat, M (Ferrat, Marion)[1]
刊名GEOCHIMICA ET COSMOCHIMICA ACTA
2011-11-01
卷号75期号:21页码:6374-6399
DOI10.1016/j.gca.2011.08.025
文献子类期刊论文
英文摘要

The Asian Monsoon forms an important part of the earth's climate system, yet our understanding of the past interactions between its different sub-systems, the East Asian and Indian monsoons, and between monsoonal winds and other prevailing wind currents such as the Westerly jet, is limited, particularly in central Asia. This in turn affects our ability to develop climate models capable of accurately predicting future changes in atmospheric circulation patterns and monsoon intensities in Asia. Provenance studies of mineral dust deposited in terrestrial settings such as peat bogs can address this problem directly, by offering the possibility to examine past deposition rates and wind direction, and hence reconstruct past atmospheric circulation patterns. However, such studies are challenged by several issues, most importantly the identification of proxies that unambiguously distinguish between the different potential dust sources and that are independent of particle size. In addition, a single analytical method that is suitable for sample preparation of both dust source (i.e. desert sand, soil) and receptor (i.e. dust archive such as peat or soil profiles) material is desirable in order to minimize error propagation derived from the experimental and analytical work. Here, an improved geochemical framework of provenance tracers to study atmospheric circulation patterns and palaeomonsoon variability in central Asia is provided, by combining for the first time mineralogical as well as major and trace elemental (Sc, Y, Th and the rare earth elements) information on Chinese (central Chinese loess plateau, northern Qaidam basin and Taklamakan, Badain Juran and Tengger deserts), Indian (Thar desert) and Tibetan (eastern Qinghai-Tibetan Plateau) dust sources. Quartz, feldspars and clay minerals are the major constituents of all studied sources, with highly variable calcite contents reflected in the CaO concentrations. Chinese and Tibetan dust sources are enriched in middle REE relative to the upper continental crust and average shale but the Thar desert has a REE signature distinctly different from all other dust sources. There are significant differences in major, trace and REE compositions between the coarse and fine fractions of the surface sands, with the finest <4 mu m fraction enriched in Al(2)O(3), Fe(2)O(3), MnO, MgO and K(2)O and the <32 mu m fractions in Sc, Y, Th and the REE relative to the coarse fractions. The <4 mu m fraction best represents the bulk REE geochemistry of the samples. The provenance tracers Y/Sigma REE, La/Er, La/Gd, Gd/Er, La/Yb, Y/Tb, Y/La, Y/Nd and to a certain extent the europium anomaly Eu/Eu* (all REE normalized to post-Archean Australian shale, PAAS) are particle size-independent tracers, of which combinations of Y/Sigma REE, La/Yb, Y/Tb, Y/La and Eu/Eu* can be used to distinguish the Thar desert, the Chinese deserts, the Chinese loess plateau and the Tibetan soils. Their independence upon grain size means that these tracers can be applied to the long-range provenance tracing of Asian dust even when only bulk samples are available in the source region. Combinations of La/Th, Y/Tb, Y/Sigma REE, Sc/La and Y/Er distinguish the Tibetan soils from the Chinese loess plateau and the Chinese deserts. La/Th and notably Th/Sigma REE isolate the signature of the Badain Juran desert and the combination of Sc/La and Y/Er that of the Taklamakan desert. The similarity in all trace and REE-based provenance tracers between the northern Qaidam basin and Tengger desert suggests that these two deposits may have a common aeolian source.

语种英语
内容类型期刊论文
源URL[http://ir.ieecas.cn/handle/361006/10330]  
专题地球环境研究所_古环境研究室
通讯作者Sun, YB (Sun, Youbin)[3]; Ferrat, M (Ferrat, Marion)[1]
作者单位1.Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK;
2.State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment,Chinese Academy of Sciences, Xi’An 710075, China;
3.Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan;
4.Department of Civil Engineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh, India
5.Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK;
推荐引用方式
GB/T 7714
Najorka, J ,Sinha, R ,Gupta, S ,et al. Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2011,75(21):6374-6399.
APA Najorka, J .,Sinha, R .,Gupta, S .,Tada, R .,Sun, YB .,...&Ferrat, M .(2011).Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau.GEOCHIMICA ET COSMOCHIMICA ACTA,75(21),6374-6399.
MLA Najorka, J ,et al."Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau".GEOCHIMICA ET COSMOCHIMICA ACTA 75.21(2011):6374-6399.
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