气候变化领域集成服务门户(CCPortal): A seawater throttle on H2 production in Precambrian serpentinizing systems

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DOI	10.1073/pnas.1921042117
	A seawater throttle on H2 production in Precambrian serpentinizing systems
	Tutolo B.M.; Seyfried W.E.; Jr.; Tosca N.J.
发表日期	2020
ISSN	0027-8424
起始页码	14756
结束页码	14763
卷号	117 期号:26
英文摘要	Since the initial discovery of low-temperature alkaline hydrothermal vents off the Mid-Atlantic Ridge axis nearly 20 y ago, the observation that serpentinizing systems produce abundant H2 has strongly influenced models of atmospheric evolution and geological scenarios for the origin of life. Nevertheless, the principal mechanisms that generate H2 in these systems, and how secular changes in seawater composition may have modified serpentinization-driven H2 fluxes, remain poorly constrained. Here, we demonstrate that the dominant mechanism for H2 production during low-temperature serpentinization is directly related to a Si deficiency in the serpentine structure, which itself is caused by low SiO2(aq) concentrations in serpentinizing fluids derived from modern seawater. Geochemical calculations explicitly incorporating this mechanism illustrate that H2 production is directly proportional to both the SiO2(aq) concentration and temperature of serpentinization. These results imply that, before the emergence of silica-secreting organisms, elevated SiO2(aq) concentrations in Precambrian seawater would have generated serpentinites that produced up to two orders of magnitude less H2 than their modern counterparts, consistent with Fe-oxidation states measured on ancient igneous rocks. A mechanistic link between the marine Si cycle and off-axis H2 production requires a reevaluation of the processes that supplied H2 to prebiotic and early microbial systems, as well as those that balanced ocean–atmosphere redox through time. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Atmosphere redox state; Origins of life; Precambrian; Serpentinization
语种	英语
scopus关键词	hydrogen; iron; magnesium; sea water; serpentine; silicon; silicon dioxide; hydrogen; sea water; Article; chemical reaction; chemical structure; concentration (parameter); controlled study; crystallography; evolution; geochemical analysis; geographic and geological phenomena; lithosphere; low temperature; mineralogy; oxidation reduction state; pH; Precambrian; priority journal; serpentinization; serpentinizing system; thermodynamics; atmosphere; chemistry; evolution; geology; hydrothermal vent; oxidation reduction reaction; Atmosphere; Biological Evolution; Earth Sciences; Earth, Planet; Hydrogen; Hydrothermal Vents; Iron; Oxidation-Reduction; Seawater; Silicon Dioxide
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160898
作者单位	Tutolo, B.M., Department of Geoscience, University of Calgary, Calgary, AB T2N 1N4, Canada; Seyfried, W.E., Jr., Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, United States; Tosca, N.J., Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, United Kingdom
推荐引用方式 GB/T 7714	Tutolo B.M.,Seyfried W.E.,Jr.,et al. A seawater throttle on H2 production in Precambrian serpentinizing systems[J],2020,117(26).
APA	Tutolo B.M.,Seyfried W.E.,Jr.,&Tosca N.J..(2020).A seawater throttle on H2 production in Precambrian serpentinizing systems.Proceedings of the National Academy of Sciences of the United States of America,117(26).
MLA	Tutolo B.M.,et al."A seawater throttle on H2 production in Precambrian serpentinizing systems".Proceedings of the National Academy of Sciences of the United States of America 117.26(2020).