Thermal history of the enstatite chondrites from silica polymorphs

	Thermal history of the enstatite chondrites from silica polymorphs
	Kimura, M ; Weisberg, MK ; Lin, Y ; Suzuki, A ; Ohtani, E ; Okazaki, R
刊名	METEORITICS & PLANETARY SCIENCE
	2005-06-01
卷号	40 期号:6 页码:855-868
ISSN号	1086-9379
文献子类	Article
英文摘要	Here we report the results of our petrologic and mineralogical study of enstatite (E) chondrites in order to explore their thermal histories. We studied silica phases in 20 E chondrites by laser micro Raman spectroscopy to determine the silica polymorphs they contain. Silica phases are commonly present in E chondrites and their polymorphs reflect the physical conditions of formation. The samples studied here include EH3-5, EL3-6, E chondrite melt rocks, and an anomalous E chondrite. We identified quartz, tridymite, cristobalite, and silica glass in the samples studied. EH4-5 and EH melt rocks are divided into high and low temperature classes based on niningerite-alabandite solid solutions. EH3, EL3, and some EH melt rocks of the high temperature class contain tridymite and cristobalite. We suggest that tridymite and cristobalite crystallized in chondrules and E chondrite melts, followed by rapid cooling, leading to the survival of these silica polymorphs. EH4 and EL4 chondrites also contain tridymite and cristobalite in their chondrules, indicating that these silica polymorphs survived low temperature metamorphism (as estimated from opaque mineral geothermometers) because of the sluggishness of the transition to a more stable polymorph. Tridymite and cristobalite in EL6 chondrites reflect the high temperature processes experienced by these meteorites. On the other hand, some EH5 chondrites and EH melt rocks of the low temperature class contain quartz, which may be a product of the transition from tridymite or cristobalite during a long period of low temperature metamorphism. Although the thermal history of E chondrites have been previously estimated from opaque minerals, such compositions mainly reflect low temperature processes. However, we can reconstruct the primordial thermal processes and subsequent cooling histories of E chondrites from their silica polymorphs. The E chondrites have complicated thermal histories, which produced the observed variations among them.
WOS关键词	HIGH-PRESSURE ; SINOITE SI2N2O ; MELT ROCKS ; SHOCK ; METEORITE ; EH ; CRYSTALLIZATION ; CLASSIFICATION ; METAMORPHISM ; MINERALOGY
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	METEORITICAL SOC
WOS记录号	WOS:000231812900005
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/64859]
专题	中国科学院地质与地球物理研究所
通讯作者	Kimura, M
作者单位	1.Ibaraki Univ, Fac Sci, Mito, Ibaraki 3108512, Japan 2.CUNY, Dept Phys Sci, Kingsborough Coll, Brooklyn, NY 11235 USA 3.Amer Museum Nat Hist, Dept Earth & Planetary Sci, New York, NY 10024 USA 4.Chinese Acad Sci, State Key Lab Lithosphere Tecton Evolut, Inst Geol & Geophys, Beijing 100029, Peoples R China 5.Tohoku Univ, Grad Sch Sci, Inst Mineral Petrol & Econ Geol, Sendai, Miyagi 9808578, Japan 6.Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan
推荐引用方式 GB/T 7714	Kimura, M,Weisberg, MK,Lin, Y,et al. Thermal history of the enstatite chondrites from silica polymorphs[J]. METEORITICS & PLANETARY SCIENCE,2005,40(6):855-868.
APA	Kimura, M,Weisberg, MK,Lin, Y,Suzuki, A,Ohtani, E,&Okazaki, R.(2005).Thermal history of the enstatite chondrites from silica polymorphs.METEORITICS & PLANETARY SCIENCE,40(6),855-868.
MLA	Kimura, M,et al."Thermal history of the enstatite chondrites from silica polymorphs".METEORITICS & PLANETARY SCIENCE 40.6(2005):855-868.