气候变化领域集成服务门户(CCPortal): Theoretical Predictions Versus Environmental Observations on Serpentinization Fluids: Lessons From the Samail Ophiolite in Oman

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DOI	10.1029/2020JB020756
	Theoretical Predictions Versus Environmental Observations on Serpentinization Fluids: Lessons From the Samail Ophiolite in Oman
	Leong J.A.M.; Howells A.E.; Robinson K.J.; Cox A.; Debes R.V.; II; Fecteau K.; Prapaipong P.; Shock E.L.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Thermodynamic calculations provide valuable insights into the reactions that drive the profound fluid transformations during serpentinization, where surface fluids are transformed into some of the most reduced and alkaline fluids on Earth. However, environmental observations usually deviate from thermodynamic predictions, especially those occurring at low temperatures where equilibrium is slowly reached. In this work, we analyzed 138 low-temperature (<40°C) fluids from the Samail ophiolite in Oman to test thermodynamic predictions with environmental observations. Four fluid types were identified through this work. (i) Type 1 circumneutral (pH 7–9) fluids result from fluid interactions with serpentinized rocks common in the shallow subsurface. (ii) Fluids with pH ranging from 9 to 11 and low Si concentrations are products of intermediate stages of serpentinization. (iii) Type 2 hyperalkaline (pH > 11) fluids approach equilibrium with diopside, and with serpentine and brucite actively forming during advanced stages of serpentinization. Lastly, (iv) most fluids sampled in this work deviate from predicted equilibrium compositions and depict various degrees of mixing between Type 1 and 2 fluids. Mixed fluids fall within the same pH range but have considerably higher dissolved Si than intermediate-type fluids. Hyperalkaline fluids exhibit variable degrees of mixing despite maintaining pH > 11, implying strong buffering capacity of serpentinization-generated fluids. Overall, this work demonstrates that predicted and measured compositions of serpentinization-derived fluids can be reconciled using a combination of equilibrium and fluid-transport simulations. This work substantiates these calculations as useful tools in exploring serpentinization reactions in continents and perhaps in other low-temperature environments on Earth and beyond. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Geochemical modeling; hyperalkaline fluids; Oman ophiolite; serpentinization; spring chemistry; thermodynamics
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187244
作者单位	Group Exploring Organic Processes in Geochemistry (GEOPIG), Arizona State University, Tempe, AZ, United States; School of Earth & Space Exploration, Arizona State University, Tempe, AZ, United States; School of Life Sciences, Arizona State University, Tempe, AZ, United States; School of Molecular Sciences, Arizona State University, Tempe, AZ, United States; Laboratory Exploring Geobiochemical Engineering and Natural Dynamics (LEGEND), Montana Technological University, Butte, MT, United States; Now at Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States
推荐引用方式 GB/T 7714	Leong J.A.M.,Howells A.E.,Robinson K.J.,et al. Theoretical Predictions Versus Environmental Observations on Serpentinization Fluids: Lessons From the Samail Ophiolite in Oman[J],2021,126(4).
APA	Leong J.A.M..,Howells A.E..,Robinson K.J..,Cox A..,Debes R.V..,...&Shock E.L..(2021).Theoretical Predictions Versus Environmental Observations on Serpentinization Fluids: Lessons From the Samail Ophiolite in Oman.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Leong J.A.M.,et al."Theoretical Predictions Versus Environmental Observations on Serpentinization Fluids: Lessons From the Samail Ophiolite in Oman".Journal of Geophysical Research: Solid Earth 126.4(2021).