气候变化领域集成服务门户(CCPortal): Groundwater mixing in an alkaline paleolake: Eocene Green River Formation; Wyoming

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DOI	10.1016/j.palaeo.2020.110038
	Groundwater mixing in an alkaline paleolake: Eocene Green River Formation; Wyoming
	Baddouh M.; Carroll A.R.; Jagniecki E.A.; Beard B.L.; Lowenstein T.K.; Johnson C.M.
发表日期	2021
ISSN	0031-0182
卷号	561
英文摘要	Tufa in the Little Mesa area of the northern Bridger Basin has been interpreted to record carbonate deposition via subaqueous and subaerial springs emanating near the shoreline of Eocene Lake Gosiute. Sedimentary facies record an overall transgression, culminating with mound structures that reach up to 9 m in height and 40 m in diameter. Mounds exhibit a strong positive, linear covariance between δ13C and δ18O, defining a slope of ~1. Similar trends occur in many other paleolake deposits, where they are interpreted to reflect changes in evaporation, atmospheric CO2 exchange, and organic matter burial. However, δ13C and δ18O in this study also covary strongly with 87Sr/86Sr, a new finding that is inconsistent with previously proposed mechanisms. We conclude that Little Mesa isotopic trends reflect mixing of groundwater with low 87Sr/86Sr, δ18O and δ13C and lake water with opposite characteristics. Low 87Sr/86Sr in groundwater likely resulted from interaction with marine carbonate strata within the Sevier fold and thrust belt to the west, whereas drainage from Precambrian-cored uplifts that bounded Lake Gosiute to the north, east, and south was responsible for higher lake water ratios. Little Mesa carbonate facies are all less radiogenic than any time-equivalent facies near the center of the basin, implying horizontal and vertical gradients in Lake Gosiute 87Sr/86Sr. Previous studies have shown that the lowest 87Sr/86Sr in basin center deposits correspond to lake highstands. Results of this study support the hypothesis that climatic modulation of surface runoff and spring emanations from the Sevier belt were principally responsible for precessional-scale expansions and contractions of Lake Gosiute. More broadly, groundwater discharge may represent an important but underappreciated contributor to covariance between 87Sr/86Sr ratios, δ13C and δ18O in closed paleolake systems. © 2020 Elsevier B.V.
语种	英语
scopus关键词	alkalinity; carbonate rock; deposition velocity; discharge; drainage; Eocene; fold and thrust belt; groundwater resource; hydrogeology; lithostratigraphy; paleolimnology; reconstruction; runoff; Bridger Basin; Green River; United States; Wyoming
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150252
作者单位	Department of Geoscience, University of Wisconsin, Madison, WI 53706, United States; Utah Geological Survey, Salt Lake City, UT 84114, United States; Department of Geological Sciences and Environmental Studies, Binghamton University, Binghamton, NY 13902, United States
推荐引用方式 GB/T 7714	Baddouh M.,Carroll A.R.,Jagniecki E.A.,et al. Groundwater mixing in an alkaline paleolake: Eocene Green River Formation; Wyoming[J],2021,561.
APA	Baddouh M.,Carroll A.R.,Jagniecki E.A.,Beard B.L.,Lowenstein T.K.,&Johnson C.M..(2021).Groundwater mixing in an alkaline paleolake: Eocene Green River Formation; Wyoming.Palaeogeography, Palaeoclimatology, Palaeoecology,561.
MLA	Baddouh M.,et al."Groundwater mixing in an alkaline paleolake: Eocene Green River Formation; Wyoming".Palaeogeography, Palaeoclimatology, Palaeoecology 561(2021).