气候变化领域集成服务门户(CCPortal): The Ductile-to-Brittle Transition Recorded in the Balmuccia Peridotite Body, Italy: Ambient Temperature for the Onset of Seismic Rupture in Mantle Rocks

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DOI	10.1029/2019JB017385
	The Ductile-to-Brittle Transition Recorded in the Balmuccia Peridotite Body, Italy: Ambient Temperature for the Onset of Seismic Rupture in Mantle Rocks
	Ueda T.; Obata M.; Ozawa K.; Shimizu I.
发表日期	2020
ISSN	21699313
卷号	125 期号:2
英文摘要	To constrain the conditions of the brittle-ductile transition in peridotite, we studied the deformation sequence of a small-displacement fault system developed in the Balmuccia peridotite body, northern Italy. The ambient pressure-temperature conditions of the deformation were estimated using equilibrium mineral assemblages and mineral compositions. Fault-related deformed rocks, including pseudotachylytes, cataclasites, and mylonites, were classified into three groups according to the metamorphic facies at the time of their formation: Group 1 consists of mylonites, cataclasites, and pseudotachylytes of the spinel-lherzolite facies; Group 2 consists of cataclasite and pseudotachylyte, but no mylonite, of the plagioclase-lherzolite facies; and Group 3 consists of cataclasite and pseudotachylyte of a lower-grade hydrous facies. Cataclasite of the spinel-lherzolite facies coeval with fault-vein pseudotachylyte was identified for Group 1 and ambient temperature of the earthquake was determined by applying geothermometers to the mylonite and cataclasite. Among the deformed rocks of the spinel-lherzolite facies (Group 1), mylonite is truncated by veins of pseudotachylyte. However, the mineral compositions of the mylonite and the cataclasite associated with the pseudotachylyte are essentially identical, yielding a temperature for the ductile-to-brittle transition in the peridotite of ~720 °C at a pressure of ~0.6–1.6 GPa. In the pressure range, low-pressure side, which overlaps with conditions of surrounding crustal rocks, is more consistent with obtained fault structures and regional tectonics. This condition lies on a geotherm of an oceanic lithosphere of the age of ~10 Ma and is consistent with a predicted temperature and depth using published flow laws of olivine. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Brittle-ductile transition; Mantle; Mylonite; Peridotite; Pseudotachylyte; Shear localization
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/187968
作者单位	Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University, Kyoto, Japan; Department of Earth and Planetary Science, School of Science, The University of Tokyo, Tokyo, Japan
推荐引用方式 GB/T 7714	Ueda T.,Obata M.,Ozawa K.,et al. The Ductile-to-Brittle Transition Recorded in the Balmuccia Peridotite Body, Italy: Ambient Temperature for the Onset of Seismic Rupture in Mantle Rocks[J],2020,125(2).
APA	Ueda T.,Obata M.,Ozawa K.,&Shimizu I..(2020).The Ductile-to-Brittle Transition Recorded in the Balmuccia Peridotite Body, Italy: Ambient Temperature for the Onset of Seismic Rupture in Mantle Rocks.Journal of Geophysical Research: Solid Earth,125(2).
MLA	Ueda T.,et al."The Ductile-to-Brittle Transition Recorded in the Balmuccia Peridotite Body, Italy: Ambient Temperature for the Onset of Seismic Rupture in Mantle Rocks".Journal of Geophysical Research: Solid Earth 125.2(2020).