气候变化领域集成服务门户(CCPortal): CO2 Induced a Small Water Solubility in Orthopyroxene and Its Implications for Water Storage in the Upper Mantle

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DOI	10.1029/2019JB018745
	CO2 Induced a Small Water Solubility in Orthopyroxene and Its Implications for Water Storage in the Upper Mantle
	Guo X.; Bai J.; Wang C.; Wu X.; Zhou X.
发表日期	2020
ISSN	21699313
卷号	125 期号:2
英文摘要	To investigate the effect of CO2 on water solubility in orthopyroxene coexisting with H2O-CO2 as a buffering fluid, high-pressure experiments were conducted at pressures of 1.5 and 3 GPa and a temperature of 1100 °C. The experiments were performed in a Walker-type multianvil assembly using natural orthopyroxene with various CO2 to CO2-H2O molar ratios as a starting material. The water contents were measured by polarized Fourier transform infrared spectrometry. At 1.5 GPa and 1100 °C, the H2O solubility decreased with increasing CO2 content in the fluid. The water solubility c(H2O) could be quantitatively determined based on water fugacity f(H2O) as c(H2O) = 25.21 × f(H2O)1.24. The addition of 57% CO2 dramatically reduced the water solubility in orthopyroxene from 184 to 90 ppm. In contrast, at 3 GPa and 1100 °C, the water solubility did not change with the CO2 content in the starting material because CO2 is unstable in bulk peridotite due to the reaction between CO2 and olivine at pressures exceeding 2.2 GPa. This study confirms that the additional component in the aqueous fluid can change the water activity and fugacity, thereby directly lowering the water storage capacity in mantle minerals. As a result, previous estimates of the maximum water storage capacity in the shallow mantle may be overestimated by a factor of 3. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	FTIR; H2O-CO2 systems; orthopyroxene; upper mantle; water fugacity; water solubility
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/187940
作者单位	Key Laboratory for High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, China
推荐引用方式 GB/T 7714	Guo X.,Bai J.,Wang C.,et al. CO2 Induced a Small Water Solubility in Orthopyroxene and Its Implications for Water Storage in the Upper Mantle[J],2020,125(2).
APA	Guo X.,Bai J.,Wang C.,Wu X.,&Zhou X..(2020).CO2 Induced a Small Water Solubility in Orthopyroxene and Its Implications for Water Storage in the Upper Mantle.Journal of Geophysical Research: Solid Earth,125(2).
MLA	Guo X.,et al."CO2 Induced a Small Water Solubility in Orthopyroxene and Its Implications for Water Storage in the Upper Mantle".Journal of Geophysical Research: Solid Earth 125.2(2020).