气候变化领域集成服务门户(CCPortal): P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels

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DOI	10.1029/2020GL088804
	P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels
	Ingalls M.; Blättler C.L.; Higgins J.A.; Magyar J.S.; Eiler J.M.; Fischer W.W.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:21
英文摘要	Understanding mechanisms, rates, and drivers of past carbonate formation provides insight into the chemical evolution of Earth's oceans and atmosphere. We paired geological observations with elemental and isotope geochemistry to test potential proxies for calcium-to-alkalinity ratios (Ca:ALK). Across diverse carbonate facies from Pleistocene closed-basin lakes in Owens Valley, CA, we observed less δ44/40Ca variation than theoretically predicted (>0.75‰) for the very low Ca:ALK in these systems. Carbonate clumped isotope disequilibria implied rapid carbonate growth—kinetic isotope effects, combined with the diverse carbonate minerals present, complicated the interpretation of δ44/40Ca as a paleoalkalinity proxy. In contrast, we observed that the high phosphate concentrations are recorded by shoreline and lake bottom carbonates formed in 11 Pleistocene lakes at orders of magnitude greater concentrations than in marine carbonates. Because the maximum phosphate content of water depends on Ca:ALK, we propose that carbonate P/Ca can inform phosphate levels and thereby Ca:ALK of aqueous environments in the carbonate record. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Alkalinity; Carbonates; Earth atmosphere; Exploratory geochemistry; Isotopes; Lakes; pH; Aqueous environment; Carbonate formations; Chemical evolution; Isotope geochemistry; Kinetic isotope effects; Marine carbonates; Orders of magnitude; Phosphate concentration; Carbonation; alkalinity; calcium; carbonate; concentration (composition); paleoceanography; phosphate; Pleistocene; reaction kinetics; water chemistry
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/169494
作者单位	Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; Now at Department of Geosciences, The Pennsylvania State University, University Park, PA, United States; Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, United States; Department of Geosciences, Princeton University, Princeton, NJ, United States
推荐引用方式 GB/T 7714	Ingalls M.,Blättler C.L.,Higgins J.A.,et al. P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels[J],2020,47(21).
APA	Ingalls M.,Blättler C.L.,Higgins J.A.,Magyar J.S.,Eiler J.M.,&Fischer W.W..(2020).P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels.Geophysical Research Letters,47(21).
MLA	Ingalls M.,et al."P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels".Geophysical Research Letters 47.21(2020).