气候变化领域集成服务门户(CCPortal): Isotopic study of the source and cycle of sulfur in the Yamdrok Tso basin, Southern Tibet, China

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DOI	10.1016/j.apgeochem.2017.09.005
	Isotopic study of the source and cycle of sulfur in the Yamdrok Tso basin, Southern Tibet, China
	Feng, Jin-Liang; Chen, Feng; Hu, Hai-Ping
通讯作者	Feng, JL (通讯作者)
发表日期	2017
ISSN	0883-2927
起始页码	61
结束页码	72
卷号	85
英文摘要	This study focuses on the inland drainage basin of Yamdrok Tso (Tso means 'lake' in the Tibetan language), which lies at altitudes between 4394 and 4989 m, in southern Tibet. The basin is located in the Tethys Himalayan zone, and consists of seven lakes with different hydrological characteristics. The main purpose of the study was to investigate the source of dissolved SO42- and the sulfur cycle in the groundwater-river-lake system. We measured the hydrogeochemical composition, delta(OH2O)-O-18, delta S-34(SO4) and delta O-18(SO4) of sulfate in river, spring and lake water; the total sulfur content (S-Total) and delta S-34(Total) of total sulfur in a lake sediment core; and the delta S-34(pyrite) of pyrite in the bedrock. The results indicate that most of the rivers in the study area are characterized by a high sulfate content with values of up to 270 mg/L. In addition, the delta S-34(pyrite) of pyrite in the bedrock ranges between -4.31% and -5.77%, while the sulfate in river and spring waters has mainly negative values of delta S-34(SO4) (-7.14% to -2.02%) and delta O-18(SO4) (-13.2% to -4.04%). In contrast, the waters of closed lakes in the study basin have high values of delta S-34(SO4) (3.44% -8.58%) and delta O-18(SO4) (7.26%-10.3%). The negative delta S-34(SO4) and delta O-18(SO4) dual-isotopic composition of sulfate indicates that pyrite weathering controls the dissolved sulfate and other solutes in rivers and spring water, while the anthropogenic pollutant sulfur flux is negligible. Water is the main oxygen source for sulfate derived from the oxidation of pyrite, while Fe3+ is the main direct agent of pyrite S oxidation. The lake water and sediments in the study basin are important sinks/stores of sulfur. The delta S-34(Total) values of total sulfur in a sediment core from a closed and holomictic lake ranges between -8.5% and -44.9%. As evidenced by the strong S-34 and O-18 enrichment in the residual pool of SO42- in the lake waters, and the marked depletion of S-34 in the sediment core, the dissimilatory microbial sulfate reduction (MSR) in the lake sediments generally results in the preferential sequestration of sulfur enriched in S-32. In addition, the magnitude of S-34/S-32 fractionation between sulfate in the lake water and sedimentary total sulfur can reach up to 48.3%. This abnormally high fractionation value can be explained mainly by the reoxidation of reduced inorganic sulfur compounds, together with the dispropotionation pathway in the sediments, caused by lake level fluctuations. The changes in STotal and delta S-34(Total) values with depth in the sediment core can also be explained by the same mechanism. (C) 2017 Elsevier Ltd. All rights reserved.
关键词	MAJOR ION CHEMISTRY ACID-MINE DRAINAGE SULFATE REDUCTION DISSOLVED SULFATE BACTERIAL DISPROPORTIONATION WEATHERING PROCESSES SULFIDE OXIDATION ABIOTIC OXIDATION CO2 CONSUMPTION RIVER-BASIN
英文关键词	Sulfur source; Sulfur isotope; Oxygen isotope; Pyrite oxidation; Lake sediment; Sulfur isotope fractionation
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000413823800006
来源期刊	APPLIED GEOCHEMISTRY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258903
推荐引用方式 GB/T 7714	Feng, Jin-Liang,Chen, Feng,Hu, Hai-Ping. Isotopic study of the source and cycle of sulfur in the Yamdrok Tso basin, Southern Tibet, China[J]. 中国科学院青藏高原研究所,2017,85.
APA	Feng, Jin-Liang,Chen, Feng,&Hu, Hai-Ping.(2017).Isotopic study of the source and cycle of sulfur in the Yamdrok Tso basin, Southern Tibet, China.APPLIED GEOCHEMISTRY,85.
MLA	Feng, Jin-Liang,et al."Isotopic study of the source and cycle of sulfur in the Yamdrok Tso basin, Southern Tibet, China".APPLIED GEOCHEMISTRY 85(2017).