Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183

doi:10.1016/j.gca.2017.09.051

GIG OpenIR

	Zhang, Ai-Cheng 1,2; Bu, Yi-Fan 1; Pang, Run-Lian 1; Sakamoto, Naoya 3; Yurimoto, Hisayoshi 3,4; Chen, Li-Hui 1; Gao, Jian-Feng 5; Du, De-Hong 1; Wang, Xiao-Lei 1; Wang, Ru-Cheng 1
	Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN号	0016-7037
	2018
卷号	220 页码:125-145
DOI	10.1016/j.gca.2017.09.051
语种	英语
WOS研究方向	Geochemistry & Geophysics
摘要	Troilite-orthopyroxene intergrowths are present as a common material in the brecciated diogenite Northwest Africa (NWA) 7183. In this study, we report on the petrographic, mineralogical, and rare earth element abundances of the troilite-orthopyroxene intergrowths to constrain their origin and assess their implications for the diverse petrogenesis of diogenites. Two groups of troilite-orthopyroxene intergrowths with various grain sizes and mineral chemistry have been observed in NWA 7183. One group of intergrowths contains fine-grained (<5 mu m) olivine and chromite as inclusions in orthopyroxene (10-20 mu m in size). The other group, in which orthopyroxene is more fine-grained (<10 mu m in size), is closely associated with coarse irregular olivine grains. The orthopyroxene grains in both groups of troilite-orthopyroxene intergrowths are depleted in Cr, Al, Ti, and Ca compared with diogenitic orthopyroxene. Based on the texture and mineral chemistry, we suggest that the two groups of troilite-orthopyroxene intergrowths formed via reactions between diogenitic olivine and S-rich vapors, probably at different temperatures. The fact that some of the intergrowths are included in diogenitic lithic clasts indicates that the formation of the host diogenite should postdate the formation of the majority of troilite-orthopyroxene intergrowths. This relationship further implies that not all of the diogenites are cumulates that directly crystallized from the Vestan magma ocean. Instead, they probably originated from partial melting and recrystallization of magma ocean cumulates. The replacement of olivine by troilite and orthopyroxene intergrowths can partly explain why the expected olivine-rich lithologies were not detected at the two south pole impact basins on Vesta. (C) 2017 Elsevier Ltd. All rights reserved.
关键词	Olivine Troilite-orthopyroxene intergrowth S-rich vapor Northwest Africa 7183 Diogenite Vesta
WOS记录号	WOS:000416502300009
收录类别	SCI
引用统计
文献类型	期刊论文
条目标识符	http://ir.gig.ac.cn/handle/344008/43380
通讯作者	Zhang, Ai-Cheng
作者单位	1.Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposits Res, Nanjing 210046, Jiangsu, Peoples R China 2.Lunar & Planetary Sci Inst, Nanjing 210046, Jiangsu, Peoples R China 3.Hokkaido Univ, Creat Res Inst Sousei, Isotope Imaging Lab, Sapporo, Hokkaido 0010021, Japan 4.Hokkaido Univ, Dept Nat Hist Sci, Sapporo, Hokkaido 0600810, Japan 5.Chinese Acad Sci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550081, Guizhou, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Ai-Cheng,Bu, Yi-Fan,Pang, Run-Lian,et al. Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2018,220:125-145.
APA	Zhang, Ai-Cheng.,Bu, Yi-Fan.,Pang, Run-Lian.,Sakamoto, Naoya.,Yurimoto, Hisayoshi.,...&Wang, Ru-Cheng.(2018).Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183.GEOCHIMICA ET COSMOCHIMICA ACTA,220,125-145.
MLA	Zhang, Ai-Cheng,et al."Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183".GEOCHIMICA ET COSMOCHIMICA ACTA 220(2018):125-145.