In-situ Moissanite in Dunite: Deep Mantle Origin of Mantle Peridotite in Luobusa Ophiolite, Tibet

doi:10.1111/1755-6724.12211

	In-situ Moissanite in Dunite: Deep Mantle Origin of Mantle Peridotite in Luobusa Ophiolite, Tibet
	Liang Fenghua 3; Xu Zhiqin ; Zhao Jianan 1
刊名	ACTA GEOLOGICA SINICA-ENGLISH EDITION
	2014
卷号	88 期号:2 页码:517-529
关键词	moissanite deep mantle origin mantle peridotite Luobusa ophiolite Tibet
ISSN号	1000-9515
DOI	10.1111/1755-6724.12211
英文摘要	We report the discovery of an in-situ natural moissanite as an inclusion in the Cr-spinel from the dunite envelope of a chromitite deposit in Luobusa ophiolite, Tibet. The moissanite occurs as a twin crystal interpenetrated by two quadrilateral signal crystals with sizes of 17 m x 10 m and 20 m x 7 m, respectively. The moissanite is green with parallel extinction. The absorption peaks in its Raman spectra are at 967-971 cm(-1), 787-788 cm(-1), and 766 cm(-1). The absorption peaks in the infrared spectra are at 696 cm(-1), 767 cm(-1), 1450 cm(-1), and 1551 cm(-1), which are distinctly different from the peaks for synthetic silicon carbide. Moissanites have been documented to form in ultra-high pressure, high temperature, and extremely low fO(2) environments and their C-13-depleted compositions indicate a lower mantle origin. Combined with previous studies about other ultra-high pressure and highly reduced minerals in Luobusa ophiolite, the in-situ natural moissanite we found indicates a deep mantle origin of some materials in the mantle sequence of Luobusa ophiolite. Further, we proposed a transformation model to explain the transfer process of UHP materials from the deep mantle to ophiolite sequence and then to the supra-subduction zone environment. Interactions between the crown of the mantle plume and mid-ocean ridge are suggested to be the dominant mechanism.
学科主题	火成岩岩石学
WOS关键词	ALPHA-SILICON CARBIDE ; SOUTHERN TIBET ; HIGH-PRESSURE ; PODIFORM CHROMITITES ; INFRARED-SPECTROSCOPY ; CRYSTAL-CHEMISTRY ; RIDGE INTERACTION ; HIGH-TEMPERATURE ; DIAMOND-BEARING ; MELT-ROCK
WOS研究方向	Geology
语种	英语
出版者	WILEY-BLACKWELL
WOS记录号	WOS:000335451300010
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40574]
专题	中国地质科学院地质研究所
作者单位	1.Chinese Acad Geol Sci, Inst Geol, State Key Lab Continental Tecton & Dynam, Beijing 100037, Peoples R China 2.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China 3.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Liang Fenghua,Xu Zhiqin,Zhao Jianan. In-situ Moissanite in Dunite: Deep Mantle Origin of Mantle Peridotite in Luobusa Ophiolite, Tibet[J]. ACTA GEOLOGICA SINICA-ENGLISH EDITION,2014,88(2):517-529.
APA	Liang Fenghua,Xu Zhiqin,&Zhao Jianan.(2014).In-situ Moissanite in Dunite: Deep Mantle Origin of Mantle Peridotite in Luobusa Ophiolite, Tibet.ACTA GEOLOGICA SINICA-ENGLISH EDITION,88(2),517-529.
MLA	Liang Fenghua,et al."In-situ Moissanite in Dunite: Deep Mantle Origin of Mantle Peridotite in Luobusa Ophiolite, Tibet".ACTA GEOLOGICA SINICA-ENGLISH EDITION 88.2(2014):517-529.