气候变化领域集成服务门户(CCPortal): Hidden intact coesite in deeply subducted rocks

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DOI	10.1016/j.epsl.2021.116763
	Hidden intact coesite in deeply subducted rocks
	Taguchi T.; Kouketsu Y.; Igami Y.; Kobayashi T.; Miyake A.
发表日期	2021
ISSN	0012821X
卷号	558
英文摘要	The stabilization of coesite is a diagnostic indicator of ultrahigh-pressure metamorphism and in many cases it implies that a rock has been subducted to a minimum depth of 80 km. Coesite typically occurs as rare relicts in rigid host minerals, but most commonly transforms into α-quartz pseudomorphs during exhumation. The abundance of coesite-bearing rocks in orogens worldwide is a contentious issue in the petrological community, despite evidence from numerical modeling that suggests that coesite formation should be a common geological process during ultrahigh-pressure metamorphism. This knowledge gap must be addressed to improve the understanding of the geological aspects of subduction-zone geodynamics. Here we report that minuscule coesites (<20 μm) occur as abundant inclusions in garnet-rich layers from the Italian Western Alps. The discovery of such intact inclusions may fill the gaps in the predicted and observed abundances of coesite worldwide. Through integrated approaches with resolutions down to the nano-scale, we show that these garnet-hosted inclusions are composed entirely of coesite. Our results suggest that common coesite-derived quartz pseudomorphs are less typical structures in ultrahigh-pressure metamorphic rocks and the minuscule coesite in many rocks may be overlooked because of its size. These findings open up new research directions for constraining the extent of deeply subducted rocks and their rheology. © 2021 Elsevier B.V.
关键词	coesite phase transition quartz pseudomorph Raman spectroscopy transmission electron microscopy
英文关键词	Garnets; Geology; Nanotechnology; Quartz; Diagnostic indicators; Geological process; Integrated approach; Knowledge gaps; Subduction zones; Typical structures; Ultra-high pressure metamorphisms; Ultra-high-pressure metamorphic rocks; Metamorphic rocks; coesite; numerical model; phase transition; pseudomorph; quartz; Raman spectroscopy; subduction; transmission electron microscopy; ultrahigh pressure metamorphism; Alps; Italy; Western Alps; Indicator indicator
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203303
作者单位	Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan; Department of Earth Sciences, Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, 169-8050, Japan; Department of Earth and Planetary Science, Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8601, Japan; Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, 464-8601, Japan; Faculty of Health and Sports, Nagoya Gakuin University, Aichi, 480-1298, Japan
推荐引用方式 GB/T 7714	Taguchi T.,Kouketsu Y.,Igami Y.,et al. Hidden intact coesite in deeply subducted rocks[J],2021,558.
APA	Taguchi T.,Kouketsu Y.,Igami Y.,Kobayashi T.,&Miyake A..(2021).Hidden intact coesite in deeply subducted rocks.Earth and Planetary Science Letters,558.
MLA	Taguchi T.,et al."Hidden intact coesite in deeply subducted rocks".Earth and Planetary Science Letters 558(2021).