Evidence for early (>= 12.7 Ma) eolian dust impact on river chemistry in the northeastern Tibetan Plateau

doi:10.1016/j.epsl.2019.03.022

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	Evidence for early (>= 12.7 Ma) eolian dust impact on river chemistry in the northeastern Tibetan Plateau
	Ruan, Xiaobai 1,3,4; Yang, Yibo 1,2; Galy, Albert 4; Fang, Xiaomin 1,2,3; Jin, Zhangdong 5; Zhang, Fei 5; Yang, Rongsheng 1,3,4; Deng, Li ; Meng, Qingquan 6,7; Ye, Chengcheng 1; Zhang, Weilin 1,2
通讯作者	Yang, Yibo(yangyibo@itpcas.ac.cn) ; Fang, Xiaomin(fangxm@itpcas.ac.cn)
	2019-06-01
发表期刊	EARTH AND PLANETARY SCIENCE LETTERS
ISSN	0012-821X
卷号	515 页码:79-89
摘要	As one of the largest dust sources on the Earth's surface, dryland in Central Asia gives rise to thick eolian deposits over East Asia (e.g., the Chinese Loess Plateau, CLP) and significantly influences the regional hydrochemistry in the downwind drainage areas. However, the formation of thick eolian dust deposits requires not only climatic prerequisites for dust emission and transport but also climatic and topographic conditions favourable for deposition and accumulation. The scarcity of widespread eolian deposition around the CLP before 7-8 Ma hinders a full understanding of the processes and mechanisms of Central Asian aridification. The deposition of eolian dust also impacts the hydrogeochemistry of fluvial systems and the precipitation of authigenic phases in continental sedimentary systems could be an archive for studying eolian dust dynamics when pure eolian deposits are scarce. Here, we present the Ca-Mg-Sr concentrations and Sr-87/Sr-86 isotope compositions of bulk carbonates in a new fluvial sequence (12.7-4.8 Ma) of the Xining Basin. The Mg/Ca and Sr/Ca ratios of the carbonate describe a power law relationship with a power coefficient of 0.8, lower than the coefficient characteristic of prior calcite precipitation (PCP). An input of eolian dust with the dissolution of Mg-rich carbonate is likely responsible for the deviation from a pure PCP process. The bulk carbonates also show a general decrease of Sr-87/Sr-86 ratios from 12.7 to 4.8 Ma, with a transition around 8.6 Ma revealed by lower Sr/Mg ratios. The comparison of these proxies to a previously reported fluvial section (12.2-5.1 Ma) in the Linxia Basin, similar to 200 km to the southeast, shows that the Sr-87/Sr-86 ratios of the bulk carbonates and water-soluble salts in the Linxia Basin are around 0.7098, which is 0.0018 lower than those in the Xining Basin before 8.6 Ma, but shows a significant rise between 8.6 and 7.0 Ma. The two basins share the same range of carbonate Sr-87/Sr-86 ratios when sediments are younger than 7 Ma. For the last 7 Myrs, the evolution of the Sr-87/Sr-86 ratios in bulk carbonates of fluvial sediments and Pliocene-Quaternary eolian deposits found in the Xining Basin are similar to those in typical eolian red clays/loess-palaeosol sequences on the CLP. These results suggest a transition of the hydrochemical regime at 8.6 Ma in the Linxia Basin from a catchment only influenced by the weathering of its bedrock to one significantly impacted by eolian dust input. In the Xining Basin, the carbonate elemental and Sr-87/Sr-86 ratios are consistent with a hydrochemistry more impacted by the presence of the eolian dust. There, the dust input occurred earlier, at >= 12.7 Ma, though it has strengthened since 8.6 Ma. The eolian dust impact on fluvial systems in the Xining Basin was much earlier than in the Linxia Basin and also preceded the initial accumulation of widespread eolian red clays on the CLP (7-8 Ma), suggesting a temporally propagating and spatially stepwise expansion of eolian dust delivery across the Asian inland during the late Cenozoic. (C) 2019 Elsevier B.V. All rights reserved.
关键词	eolian dust Sr isotopes carbonate Linxia Basin Xining Basin
DOI	10.1016/j.epsl.2019.03.022
关键词[WOS]	CHINESE LOESS PLATEAU ; XINING BASIN ; PHASED UPLIFT ; CARBONATE ; EVOLUTION ; DEPOSITS ; CALCITES ; PACIFIC ; MONSOON ; ORIGIN
收录类别	SCI ; SCI
语种	英语
资助项目	National Natural Science Foundation of China[41771236] ; National Natural Science Foundation of China[41620104002] ; National Natural Science Foundation of China[41872098] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA20070201] ; External Cooperation Program of the Chinese Academy of Sciences[131C11KYSB20160072] ; Youth Innovation Promotion Association of the Chinese Academy of Sciences[2018095] ; State Key Laboratory of Loess and Quaternary Geology[SKLLQG1841] ; China Scholarship Council
WOS研究方向	Geochemistry & Geophysics
项目资助者	National Natural Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; External Cooperation Program of the Chinese Academy of Sciences ; Youth Innovation Promotion Association of the Chinese Academy of Sciences ; State Key Laboratory of Loess and Quaternary Geology ; China Scholarship Council
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000466251400008
出版者	ELSEVIER SCIENCE BV
引用统计	被引频次：16[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.ieecas.cn/handle/361006/13943
专题	加速器质谱中心
通讯作者	Yang, Yibo; Fang, Xiaomin
作者单位	1.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Continental Collis & Plateau Uplift, Beijing 100101, Peoples R China 2.Chinese Acad Sci, CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.Univ Lorraine, CNRS, UMR7358, Ctr Rech Petrog & Geochim, F-54500 Vandoeuvre Les Nancy, France 5.Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710075, Shaanxi, Peoples R China 6.Lanzhou Univ, Sch Earth Sci, Lanzhou 730000, Gansu, Peoples R China 7.Lanzhou Univ, Key Lab Western Chinas Mineral Resources Gansu Pr, Lanzhou 730000, Gansu, Peoples R China
推荐引用方式 GB/T 7714	Ruan, Xiaobai,Yang, Yibo,Galy, Albert,et al. Evidence for early (>= 12.7 Ma) eolian dust impact on river chemistry in the northeastern Tibetan Plateau[J]. EARTH AND PLANETARY SCIENCE LETTERS,2019,515:79-89.
APA	Ruan, Xiaobai.,Yang, Yibo.,Galy, Albert.,Fang, Xiaomin.,Jin, Zhangdong.,...&Zhang, Weilin.(2019).Evidence for early (>= 12.7 Ma) eolian dust impact on river chemistry in the northeastern Tibetan Plateau.EARTH AND PLANETARY SCIENCE LETTERS,515,79-89.
MLA	Ruan, Xiaobai,et al."Evidence for early (>= 12.7 Ma) eolian dust impact on river chemistry in the northeastern Tibetan Plateau".EARTH AND PLANETARY SCIENCE LETTERS 515(2019):79-89.