Iron isotopic constraints on the genesis of Bayan Obo ore deposit, Inner;Mongolia, China

doi:10.1016/j.precamres.2013.06.004

	Iron isotopic constraints on the genesis of Bayan Obo ore deposit, Inner;Mongolia, China
	Sun, Jian 3; Zhu, Xiangkun ; Chen, Yuelong 1; Fang, Nan 1
刊名	PRECAMBRIAN RESEARCH
	2013
卷号	235 页码:88-106
关键词	Bayan Obo Iron isotopes Iron ore REE Carbonatite Magmatic origin
ISSN号	0301-9268;EI 1872-7433
DOI	10.1016/j.precamres.2013.06.004
英文摘要	The giant polymetallic Bayan Obo REE-Nb-Fe ore deposit is the largest REE deposit in the world. Despite the fact that a great number of works have been done on the deposit, its origin remains controversial. Various genetic models have been proposed, including sedimentary origin, magmatic origin, hydrothermal origin or origin with multiple processes. Here the Fe isotope compositions of different types of rocks from the deposit and related geological formations, such as carbonatites, mafic dykes, and Mesoproterozoic sedimentary iron formation and carbonates, are systematically investigated. For the ore deposit, the average delta Fe-56 values are -0.03 +/- 0.16 parts per thousand (2SD, n=14), 0.01 parts per thousand +/- 0.24 parts per thousand (2SD, n=6), -0.07 +/- 0.24 parts per thousand (2SD, n=19) for bulk samples of fine-grained iron ores, gangue rocks and ore-hosting dolomite marble, respectively; and 0.01 +/- 0.14 (2SD, n=14), 0.08 +/- 0.18 (2SD, n=3), -0.21 for the magnetite, hematite and dolomite, the main Fe oxide and carbonate minerals in the deposit. The narrow range of the near-zero delta Fe-56 values of fine-grained iron ores and Fe oxide minerals are consistent with those of magmatic products such as igneous rocks and magmatic iron ores, but different from those of sedimentary or hydrothermal products like Precambrian sedimentary iron formations and hydrothermal iron ores reported previously. The slightly negative Fe isotope values of the orehosting dolomite marble are consistent with those of the carbonatite dykes in Bayan Obo area and the typical carbonatites worldwide, but different from those of Mesoproterozoic sedimentary carbonates. The small Fe isotope fractionations between magnetite and dolomite (Delta Fe-56(magnetite-dolomite) approximate to 0.23 parts per thousand), and between hematite and magnetite (Delta Fe-56(hematite-magnetite) approximate to 0.07 parts per thousand), indicate that the ore deposit experienced a very high temperature. Overall, the Fe isotope compositions are inconsistent with either sedimentary or hydrothermal origin, but support a magmatic origin for the Bayan Obo deposit. (C) 2013 Elsevier B.V. All rights reserved.
学科主题	矿床地质
WOS关键词	MID-ATLANTIC RIDGE ; NB-FE DEPOSIT ; MOSSBAUER-SPECTROSCOPY ; MASS-SPECTROMETRY ; MANTLE SOURCE ; REE DEPOSIT ; FRACTIONATION ; ROCKS ; EARTH ; CARBONATITES
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000328522400006
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40177]
专题	中国地质科学院地质研究所
作者单位	1.CAGS, Inst Geol, State Key Lab Continental Dynam, Lab Isotope Geol,MLR, Beijing 100037, Peoples R China. 2.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China. 3.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Sun, Jian,Zhu, Xiangkun,Chen, Yuelong,et al. Iron isotopic constraints on the genesis of Bayan Obo ore deposit, Inner;Mongolia, China[J]. PRECAMBRIAN RESEARCH,2013,235:88-106.
APA	Sun, Jian,Zhu, Xiangkun,Chen, Yuelong,&Fang, Nan.(2013).Iron isotopic constraints on the genesis of Bayan Obo ore deposit, Inner;Mongolia, China.PRECAMBRIAN RESEARCH,235,88-106.
MLA	Sun, Jian,et al."Iron isotopic constraints on the genesis of Bayan Obo ore deposit, Inner;Mongolia, China".PRECAMBRIAN RESEARCH 235(2013):88-106.