气候变化领域集成服务门户(CCPortal): Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine

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DOI	10.1016/j.scib.2018.12.018
	Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine
	Su, Benxun; Zhou, Meifu; Jing, Jiejun; Robinson, Paul T.; Chen, Chen; Xiao, Yan; Liu, Xia; Shi, Rendeng; Lenaz, Davide; Hu, Yan
通讯作者	Su, BX (通讯作者)
发表日期	2019
ISSN	2095-9273
EISSN	2095-9281
起始页码	108
结束页码	121
卷号	64 期号:2
英文摘要	To investigate the factors controlling the mineralization in ophiolites we systematically compared the petrology and mineral compositions of the harzburgites/lherzolites, dunites and chromitites in the Luobusa and Purang ophiolites. Generally, the petrological features and trace element compositions of chromite and olivine in peridotite and chromitite are distinctly different between the two ophiolites. In Luobusa, boninitic melts are inferred to have interacted with the harzburgites and modified the distributions of some trace elements (e.g., Ni, Mn and V) in chromite and olivine. The subsequently formed dunites and chromitites experienced significant elemental exchange. In contrast, the Purang ophiolite contains a wider range of chromitite compositions and records diverse melt activities, such as the growth of relatively abundant secondary clinopyroxene. The metasomatic melts were enriched in Al and depleted in Si, Na and highly incompatible trace elements (e.g., Nb, Zr). Such melts resemble MORB-like melts proposed in the literature but are assumed to be more hydrous than typical MORB because of presence of hydrous minerals. The parental magmas of the Purang dunites and intermediate chromitites are inferred to be compositionally intermediate between boninitic and MORB-like melts. In addition, the more refractory nature of the Luobusa harzburgites facilitated a high Cr concentration gradient with the interacting melts, making it easier to increase Cr in the melts. Crystallization of clinopyroxene and amphibole in the Purang ophiolite accommodated significant amounts of Cr and water, respectively, and negatively affected Cr concentration and chromite crystallization. The concentration of chromite to form chromitites requires the presence of focused melt channels. (C) 2018 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
关键词	ZANGBO SUTURE ZONE POZANTI-KARSANTI OPHIOLITE IZU-BONIN-MARIANA PODIFORM CHROMITITES OCEANIC LITHOSPHERE UPPER-MANTLE TRANSITION ZONE ORTHO-PYROXENE HIGH-AL HIGH-CR
英文关键词	Chromite; Olivine; Ophiolite; Trace element; Tibet
语种	英语
WOS研究方向	Science & Technology - Other Topics
WOS类目	Multidisciplinary Sciences
WOS记录号	WOS:000460872100007
来源期刊	SCIENCE BULLETIN
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259620
推荐引用方式 GB/T 7714	Su, Benxun,Zhou, Meifu,Jing, Jiejun,et al. Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine[J]. 中国科学院青藏高原研究所,2019,64(2).
APA	Su, Benxun.,Zhou, Meifu.,Jing, Jiejun.,Robinson, Paul T..,Chen, Chen.,...&Hu, Yan.(2019).Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine.SCIENCE BULLETIN,64(2).
MLA	Su, Benxun,et al."Distinctive melt activity and chromite mineralization in Luobusa and Purang ophiolites, southern Tibet: constraints from trace element compositions of chromite and olivine".SCIENCE BULLETIN 64.2(2019).