干旱区生态环境知识资源中心(Arid): Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong-Nujiang suture zone, Tibetan Plateau

Arid

DOI	10.1002/gj.3496
	Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong-Nujiang suture zone, Tibetan Plateau
	Liu, Zhi-Bo 1; Li, Jing-Chao 2; Zhao, Tao 2; Song, Yang 1; Yuan, Guo-Li 2; Lin, Yun 2; Shao, Hua-Sheng 2
通讯作者	Yuan, Guo-Li
来源期刊	GEOLOGICAL JOURNAL
ISSN	0072-1050
EISSN	1099-1034
出版年	2020
卷号	55 期号:2 页码:1283-1299
英文摘要	Serpentinised ultramafic rocks are widely distributed in the Bangong-Nujiang suture zone (BNSZ) and show close relationship with the regional mineralisation. Here, we investigate the serpentinised ultramafic rocks from Angwu in the central segment of the BNSZ, where the primary minerals include olivine, clinopyroxene, chromite, lizardite, magnetite, and chlorite. Based on a comprehensive analysis of the results from petrography, back-scattered electron images (BSE), and energy dispersive spectrographs (EDS), as well as electron probe microanalysis (EPMA), the alteration process of the ultramafic rocks, including serpentinisation, can be divided into three stages: 1, formation of relatively Fe-rich serpentine (Mg#, 0.82), with no precipitation of magnetite; 2, formation of relatively Mg-rich serpentine (Mg#, 0.93), with precipitation of magnetite in serpentine veins; and 3, alteration of serpentine into chlorite. We computed the reactions associated with alteration process for the above stages. In addition, thermodynamic modelling in multicomponent mineral equilibrium phase diagrams indicate that during the serpentinisation process, the desilication of pyroxene in caused the enhancement of SiO2 activity and restricted the transformation from olivine to magnetite. The reaction temperature for the serpentinisation of these rocks was relatively high, and within this temperature interval (100-300 degrees C), lizardite was stable, and precipitation of magnetite was not favoured. We also evaluate the factors influencing magnetite precipitation during serpentinisation of ultramafic rocks including the composition of primitive rocks and the activity of SiO2 and temperature. Our study provides insights on the mechanism of magnetite mineralisation associated with the serpentinisation of ultramafic rocks.
英文关键词	Bangong-Nujiang suture zone (BNSZ) magnetite serpentinisation Tibetan Plateau ultramafic rocks
类型	Article
语种	英语
国家	Peoples R China
收录类别	SCI-E
WOS记录号	WOS:000512877800015
WOS关键词	BOU-AZZER OPHIOLITE ; HYDROGEN GENERATION ; ABYSSAL PERIDOTITES ; TECTONIC EVOLUTION ; EASTERN DESERT ; ANTI-ATLAS ; SERPENTINIZATION ; GEOCHRONOLOGY ; GEOCHEMISTRY ; OLIVINE
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/314599
作者单位	1.Chinese Acad Geol Sci, Inst Mineral Resources, Key Lab Metallogeny & Mineral Assessment, Beijing, Peoples R China; 2.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China
推荐引用方式 GB/T 7714	Liu, Zhi-Bo,Li, Jing-Chao,Zhao, Tao,et al. Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong-Nujiang suture zone, Tibetan Plateau[J],2020,55(2):1283-1299.
APA	Liu, Zhi-Bo.,Li, Jing-Chao.,Zhao, Tao.,Song, Yang.,Yuan, Guo-Li.,...&Shao, Hua-Sheng.(2020).Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong-Nujiang suture zone, Tibetan Plateau.GEOLOGICAL JOURNAL,55(2),1283-1299.
MLA	Liu, Zhi-Bo,et al."Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong-Nujiang suture zone, Tibetan Plateau".GEOLOGICAL JOURNAL 55.2(2020):1283-1299.