Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area

doi:10.1180/0026461056960308

	Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area
	Shi, GH ; Stockhert, B ; Cui, WY
刊名	MINERALOGICAL MAGAZINE
	2005-12-01
卷号	69 期号:6 页码:1059-1075
关键词	Kosmochlor Jadeite Omphacite Chromite Corona Texture Metasomatism Myanniar Jadeitite
ISSN号	0026-461X
DOI	10.1180/0026461056960308
文献子类	Article
英文摘要	Four distinct textures and related compositions of kosmochlor (Ko) and chromian jadeite in rocks from the Myanmar jadeitite area are described: (1) spheroidal or ellipsoidal aggregates with a corona texture surrounding relict chromite; (2) spheroidal or ellipsoidal aggregates with a core of jadeite; (3) granoblastic textures in undeformed coarse-grained clinopyroxene rocks; and (4) recrystallized fine-grained aggregates in deformed jadeitite. Nearly pure kosmochlor (97 mol.% NaCrSi2O6) was found in type 2 textures, closest to the end-member reported so far from a terrestrial rock. Sharp compositional boundaries between kosmochlor and chromian jadeite of variable composition are interpreted to be related to progressive crystallization or replacement at differing conditions. The compositions analysed plot along the kosmochlor-jadeite join. In contrast to conclusions of previous studies on the Myanmar clinopyroxenes there is no unequivocal evidence for miscibility gaps. The preservation of relict chromite in the centre of coronitic spheroidal or ellipsoidal aggregates of kosmochlor and jadeite indicates a metasomatic origin from a peridotite protolith at an inferred minimum pressure of 1.0 GPa and temperatures of 250-370 degrees C. Recrystallization during later ductile deformation of the clinopyroxene rocks in the dislocation creep regime leads to fine-grained aggregates of chromian jadeite, which are of particular gemmological interest.
WOS关键词	FLUID INCLUSIONS ; SUBDUCTION ZONE ; HIGH-PRESSURE ; UREYITE ; BURMA ; ROCKS ; CLINOPYROXENE ; SERPENTINITE ; TRANSITION ; PERIDOTITE
WOS研究方向	Mineralogy
语种	英语
出版者	MINERALOGICAL SOCIETY
WOS记录号	WOS:000235438600011
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/65690]
专题	中国科学院地质与地球物理研究所
通讯作者	Shi, GH
作者单位	1.China Univ Geosci, Beijing 100083, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 3.Ruhr Univ Bochum, Inst Geol Mineral & Geophys, D-44780 Bochum, Germany 4.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China
推荐引用方式 GB/T 7714	Shi, GH,Stockhert, B,Cui, WY. Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area[J]. MINERALOGICAL MAGAZINE,2005,69(6):1059-1075.
APA	Shi, GH,Stockhert, B,&Cui, WY.(2005).Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area.MINERALOGICAL MAGAZINE,69(6),1059-1075.
MLA	Shi, GH,et al."Kosmochlor and chromian jadeite aggregates from the Myanmar jadeitite area".MINERALOGICAL MAGAZINE 69.6(2005):1059-1075.