气候变化领域集成服务门户(CCPortal): Controls on short-term dissolved 87Sr/86Sr variations in large rivers: Evidence from the Ganga

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DOI	10.1016/j.epsl.2021.116958
	Controls on short-term dissolved 87Sr/86Sr variations in large rivers: Evidence from the Ganga–Brahmaputra
	Boral S.; Peucker-Ehrenbrink B.; Hemingway J.D.; Sen I.S.; Galy V.; Fiske G.J.
发表日期	2021
ISSN	0012821X
卷号	566
英文摘要	Variations in the marine 87Sr/86Sr record are largely driven by riverine export of weathering-derived strontium. Among the large river systems, the Ganga and the Brahmaputra deliver a disproportionately large flux of radiogenic Sr (i.e., high 87Sr/86Sr) to the ocean. Understanding the sources and processes that make these river systems such important contributors of radiogenic Sr to seawater has been the focus of many studies; extremely radiogenic silicate and carbonate rocks of the Lesser Himalayan formations impart river water with high 87Sr/86Sr values. Furthermore, dissolved 87Sr/86Sr compositions show large temporal variability in both headwater and floodplain catchments; the magnitude of these fluctuations is higher than is observed in any other major river globally. Here, we present dissolved and depth-specific suspended particulate Sr time-series data from the rivers Ganga and Brahmaputra with weekly resolution during the monsoon and monthly resolution during the non-monsoon seasons of 2010–2011. We find that dissolved 87Sr/86Sr compositions of both rivers show substantial short-term variability with week-to-week changes as large as 0.0134 87Sr/86Sr units. Dissolved 87Sr/86Sr compositions correlate strongly with suspended particulate 87Sr/86Sr compositions at all depths. To understand the short-term variability of dissolved 87Sr/86Sr, we developed a hydro-geochemical mixing model using literature-derived Sr concentration and 87Sr/86Sr values of major tributaries combined with 5-day integrated rainfall as a proxy for unavailable discharge data. Results indicate that short-term changes in dissolved 87Sr/86Sr are largely driven by spatio-temporal rainfall variability across the Ganga and Brahmaputra watersheds. We also observe strong correlations between the dissolved 87Sr/86Sr and the particulate 87Sr/86Sr along the depth-profile in both rivers as well as in other large rivers globally. Hence, we corroborate the findings from Tipper et al. (2021) and propose that in-stream interactions with radiogenic sediments during transport further contribute to dissolved 87Sr/86Sr variability. © 2021 Elsevier B.V.
关键词	87Sr/86Sr predictive hydro-geochemical model rivers Ganga Brahmaputra sediment-water interactions Sr flux time series
英文关键词	Atmospheric thermodynamics; Catchments; Dissolution; Geochemistry; Rain; Sediments; Silicate minerals; Stream flow; Strontium; Time series; Weathering; Brahmaputra; Large rivers; Predictive hydro-geochemical model; Radiogenics; River ganga brahmaputra; Sediment/water interaction; Short term; Sr fluxes; Suspended particulates; Times series; Rivers; floodplain; headwater; hydrogeochemistry; isotopic composition; radionuclide; river system; river water; sediment-water interface; strontium isotope; temporal variation; time series; Brahmaputra River; Ganges River
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203037
作者单位	Department of Earth Sciences, Indian Institute of Technology, Kanpur, UP 208016, India; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States; Department of Earth and Planetary Sciences, Harvard UniversityMA 02138, United States; Woodwell Climate Research Center, Falmouth, MA 02540, United States
推荐引用方式 GB/T 7714	Boral S.,Peucker-Ehrenbrink B.,Hemingway J.D.,等. Controls on short-term dissolved 87Sr/86Sr variations in large rivers: Evidence from the Ganga–Brahmaputra[J],2021,566.
APA	Boral S.,Peucker-Ehrenbrink B.,Hemingway J.D.,Sen I.S.,Galy V.,&Fiske G.J..(2021).Controls on short-term dissolved 87Sr/86Sr variations in large rivers: Evidence from the Ganga–Brahmaputra.Earth and Planetary Science Letters,566.
MLA	Boral S.,et al."Controls on short-term dissolved 87Sr/86Sr variations in large rivers: Evidence from the Ganga–Brahmaputra".Earth and Planetary Science Letters 566(2021).