气候变化领域集成服务门户(CCPortal): Squeezing Water From a Stone: H2O In Nominally Anhydrous Minerals From Granulite Xenoliths and Deep, Hydrous Fractional Crystallization

CCPortal

DOI	10.1029/2020JB020416
	Squeezing Water From a Stone: H2O In Nominally Anhydrous Minerals From Granulite Xenoliths and Deep, Hydrous Fractional Crystallization
	Chin E.J.; Curran S.T.; Farmer G.L.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Water is key to plate tectonics on Earth, which, in turn, is vital to the production of continental crust. Although arc lavas erupt in a volatile-rich state and calc-alkaline arc plutons are distinguished by the presence of hydrous minerals such as hornblende and biotite, the water content of arc magmas earlier in their evolution—in the deep crust—remains poorly constrained. Here, we report H2O contents in nominally anhydrous minerals measured in situ on petrographic thin sections by secondary ion mass spectrometry of Proterozoic deep crustal xenoliths from Colorado, USA. Clinopyroxene, orthopyroxene, and garnet contain average H2O contents ranging from 75–760, 233–410, and 42–139 ppm, respectively. Reconstructed bulk rock H2O contents range from ~60 to ~650 ppm. Intermineral H2O ratios overlap experimental mineral/melt D values and are used to calculate H2O of melts last in equilibrium with the xenoliths. We propose that these xenoliths represent cumulates fractionated from a primitive, hydrous (≥1 wt.% H2O) melt at high (~1 GPa) pressures, similar to conditions in modern subduction zones and potentially associated with widespread arc accretion that formed the core of North America in the Precambrian. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	arcs; continental crust; cumulate; lower crust; subduction; xenolith
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/187536
作者单位	Geosciences Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States; Department of Geological Sciences and CIRES, University of Colorado Boulder, Boulder, CO, United States
推荐引用方式 GB/T 7714	Chin E.J.,Curran S.T.,Farmer G.L.. Squeezing Water From a Stone: H2O In Nominally Anhydrous Minerals From Granulite Xenoliths and Deep, Hydrous Fractional Crystallization[J],2020,125(10).
APA	Chin E.J.,Curran S.T.,&Farmer G.L..(2020).Squeezing Water From a Stone: H2O In Nominally Anhydrous Minerals From Granulite Xenoliths and Deep, Hydrous Fractional Crystallization.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Chin E.J.,et al."Squeezing Water From a Stone: H2O In Nominally Anhydrous Minerals From Granulite Xenoliths and Deep, Hydrous Fractional Crystallization".Journal of Geophysical Research: Solid Earth 125.10(2020).