干旱区生态环境知识资源中心(Arid): Lithium isotope signatures of weathering in the hyper-arid climate of the western Tibetan Plateau

Arid

DOI	10.1016/j.gca.2020.10.021
	Lithium isotope signatures of weathering in the hyper-arid climate of the western Tibetan Plateau
	Weynell, Marc; Wiechert, Uwe; Schuessler, Jan A.
通讯作者	Weynell, M (corresponding author), Free Univ Berlin, Inst Geol Sci, Malteser Str 74-100, Berlin, Germany.
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2021
卷号	293 页码:205-223
英文摘要	This study of Lithium (Li) isotopes in surface waters and sediments in the catchment of Lake Bangong and the Upper Indus on the western Tibetan Plateau aims to identify processes that control Li isotope variations during weathering under a cold and hyper-arid climate. Additionally, Li isotope ratios in the Yarlung Tsangpo - Brahmaputra River were investigated. The lake and river sediments of Lake Bangong catchment display remarkable low delta Li-7 values between -4.7 parts per thousand and -0.6 parts per thousand relative to L-SVEC. Li isotopes in river bed sediments correlate with weathering intensity tracers such as the chemical index of alteration (CIA), K/(Na + K), or Na/Ti, and delta Li-7 values decrease continuously within the sediment cascade. These observations cannot be explained by mixing of different lithologies but reflects increasing intensity of weathering. The hyper-arid climate on the western plateau results in considerably long sediment residence times, which allows for overcoming the limitation of water availability on chemical weathering reactions. Samples from the Lake Bangong basins display low delta Li-7 values between +8.1 parts per thousand and +11.1 parts per thousand. The major inflows have dissolved delta Li-7 values of +6.1 parts per thousand and +8.9 parts per thousand. High Li/Na ratios in the stream waters indicate some contribution of hydrothermal Li. However, low delta Li-7 values in surface waters result from impeded silicate weathering processes in the thin soils. The samples from Indus headwaters and Yarlung Tsangpo provide evidence for low delta Li-7 all over the western and southern Tibetan Plateau. Using data of the Bangong Co, the Indus headwaters, and Yarlung Tsangpo, as well as published data from the northeastern plateau, we explore what controls Li isotope variation across the Tibetan plateau. Mass balance calculations suggest that similar proportions of dissolved Li and particulate Li are exported by river water and sediments on the western plateau. In contrast, high delta Li-7 values around +17 parts per thousand of the dissolved load in rivers on the northeastern Tibetan Plateau reflect a particulate Li export flux that is about five times higher than the export flux of dissolved Li. There is no first-order control by silicate weathering rates. The delta Li-7 differences largely follow the precipitation gradient across the Tibetan Plateau, which results in high net-incorporation of Li into clays on the northeastern but limits soil formation on the western Tibetan Plateau and, therefore limited, processing of lithium in the weathering zone. (C) 2020 Elsevier Ltd. All rights reserved.
英文关键词	Lithium isotopes Tibetan Plateau Cold desert Weathering regime
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000600550100011
WOS关键词	HOLOCENE ENVIRONMENTAL-CHANGES ; CO2 CONSUMPTION ; BANGONG CO ; GEOTHERMAL SYSTEMS ; YANGTZE-RIVER ; INDUS RIVER ; LI ; BASIN ; FRACTIONATION ; CONSTRAINTS
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/347920
作者单位	[Weynell, Marc; Wiechert, Uwe] Free Univ Berlin, Inst Geol Sci, Malteser Str 74-100, Berlin, Germany; [Schuessler, Jan A.] GFZ German Res Ctr Geosci, Earth Surface Geochem, Potsdam, Germany; [Weynell, Marc] Tongji Univ, Sch Ocean & Earth Sci, State Key Lab Marine Geol, Shanghai, Peoples R China
推荐引用方式 GB/T 7714	Weynell, Marc,Wiechert, Uwe,Schuessler, Jan A.. Lithium isotope signatures of weathering in the hyper-arid climate of the western Tibetan Plateau[J],2021,293:205-223.
APA	Weynell, Marc,Wiechert, Uwe,&Schuessler, Jan A..(2021).Lithium isotope signatures of weathering in the hyper-arid climate of the western Tibetan Plateau.GEOCHIMICA ET COSMOCHIMICA ACTA,293,205-223.
MLA	Weynell, Marc,et al."Lithium isotope signatures of weathering in the hyper-arid climate of the western Tibetan Plateau".GEOCHIMICA ET COSMOCHIMICA ACTA 293(2021):205-223.