气候变化领域集成服务门户(CCPortal): Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit (China): Implicated by petrography and geochemistry of Nb-bearing minerals

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DOI	10.1016/j.precamres.2020.105864
	Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit (China): Implicated by petrography and geochemistry of Nb-bearing minerals
	Liu, Shang; Ding, Lin; Fan, Hong-Rui; Yang, Kui-Feng; Tang, Yan-Wen; She, Hai-Dong; Hao, Mei-zhen
通讯作者	Liu, S (通讯作者)
发表日期	2020
ISSN	0301-9268
EISSN	1872-7433
卷号	348
英文摘要	The Bayan Obo REE-Nb-Fe deposit, which reserves the current largest REE resources globally, also hosts over 70% of China's Nb resources. Unlike many world-class carbonatite-related Nb deposits (e.g. Morro dos Seis Lagos and Araxa, Brazil) with igneous or secondary origin, Nb was mainly stored in Nb-bearing minerals (aeschynite, ilmenorutile, baotite, fergusonite etc.) of hydrothermal origin at Bayan Obo, supported by evidence from petrography, element and isotopic geochemistry. Although igneous fersmite and columbite were occasionally discovered in local carbonatite dykes, the Mesoproterozoic and Paleozoic hydrothermal metasomatism occurred in the ore-hosting dolomite, related to carbonatite intrusion and the closure of Paleo-Asian Ocean respectively, has played a more significant role during the ultimate Nb enrichment. REE, however, was significantly enriched during both the carbonatite-related magmatic and hydrothermal processes. Consequently, there was differentiated mineralization between REE and Nb in the carbonatite dykes and the ores. Niobium mineralization at Bayan Obo is rather limited in Mesoproterozoic carbonatite, whereas more extensive in the metasomatized orehosting dolomite, and generally postdating the REE mineralization at the same stage. According to mineral geochemistry, Bayan Obo aeschynite was classified into 3 groups: aeschynite-(Nd) with convex REE patterns (Group 1); aeschynite-(Ce) (Group 2) and nioboaeschynite (Group 3) with nearly flat REE patterns. Aeschynite (Group 1), ilmenorutile and fergusonite precipitated from Paleozoic hydrothermal fluids with advanced fractionation of Ce-rich REE minerals. The Mesoproterozoic hydrothermal Nb mineralization, represented by aeschynite (Group 3) and baotite, occurred postdating REE mineralization at same stage. Besides, fersmite and aeschynite (Group 2) precipitated from the Mesoproterozoic REE-unfractionated melt and hydrothermal fluids, respectively. All above Nb-bearing minerals exhibit extreme Nb-Ta fractionation as a primary geochemical characteristic of mantle-derived carbonatite. The forming age of the aeschynite megacrysts (Group 1) has not been accurately determined. However, the potential age was constrained to similar to 430 Ma or alternatively similar to 270-280 Ma subjected to subduction and granite activity, respectively. These aeschynite crystals inherited REEs from multiphase former REE mineralization, with an intermediate apparent Sm-Nd isochron age between the Mesoproterozoic and the Paleozoic REE mineralization events.
关键词	RICH CARBONATITE DYKE LA-ICP-MS INNER-MONGOLIA TRACE-ELEMENTS ORE-DEPOSIT DOLOMITE MARBLE U-PB AESCHYNITE-GROUP CONSTRAINTS NIOBIUM
英文关键词	Nb mineralization; Nb-bearing minerals; Hydrothermal; Bayan Obo REE-Nb-Fe deposit
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000567091500009
来源期刊	PRECAMBRIAN RESEARCH
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/259997
推荐引用方式 GB/T 7714	Liu, Shang,Ding, Lin,Fan, Hong-Rui,et al. Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit (China): Implicated by petrography and geochemistry of Nb-bearing minerals[J]. 中国科学院青藏高原研究所,2020,348.
APA	Liu, Shang.,Ding, Lin.,Fan, Hong-Rui.,Yang, Kui-Feng.,Tang, Yan-Wen.,...&Hao, Mei-zhen.(2020).Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit (China): Implicated by petrography and geochemistry of Nb-bearing minerals.PRECAMBRIAN RESEARCH,348.
MLA	Liu, Shang,et al."Hydrothermal genesis of Nb mineralization in the giant Bayan Obo REE-Nb-Fe deposit (China): Implicated by petrography and geochemistry of Nb-bearing minerals".PRECAMBRIAN RESEARCH 348(2020).