Study of the Precambrian BIF-iron deposits in the North China Craton: Progresses and questions

	Study of the Precambrian BIF-iron deposits in the North China Craton: Progresses and questions
	Zhang LianChang 1; Zhai MingGuo 1,2; Wan YuSheng 3; Guo JingHui 2; Dai YanPei 1; Wang ChangLe 1; Liu Li 1
刊名	ACTA PETROLOGICA SINICA
	2012-11-01
卷号	28 期号:11 页码:3431-3445
关键词	Precambrian Banded iron deposit Greenstone belts Crustal growth Ore-forming processes North China Craton
ISSN号	1000-0569
文献子类	Article
英文摘要	It is shown that regular patterns can be established for the distribution of BIF-iron deposits in the North China Craton (NCC). Large scale BIF-iron deposits mainly exist in some greenstone-belts areas such as Anshan-Benxi, eastern Hebei, Huoqiu-Wuyang, Wutai, western Shandong and Guyang etc; formation ages of BIF in the NCC cover a wide range from Paleoarchean to Early Paleoproterozoic, among which Late Neoarchean is the peak period (2.52 similar to 2.56Ga); BIF can be divided into two types, Algoma and Superior Lake. Most BIFs occurring in Neoarchean greenstone belts in the NCC belong to the former while only the Paleoproterozoic Yuanjiacun iron deposit in the Lvliang area has typical characteristics similar to Superior-type BIF. Five specific types for BIFs in the NCC can be divided on the basis of their occurrences in greenstone belts successions and their relations with rock assembly: 1) amphibolites (or hornblende plagioclase gneiss) and magnetite quartzite association; 2) amphibolites, biotite leptynite, mica quartz schist, and magnetite quartzite association; 3) biotite leptynite (or biotite quartz schist) and magnetite quartzite association; 4) biotite leptynite, sericite chlorite schist, biotite quartz schist and magnetite quartzite association; and 5) amphibolites (gneiss), marble and magnetite quartzite association. The formation era of BIFs in the NCC is in accordance with magmatic activity in Early Precambrian, but there is some deviation from the peak period of crustal growth of the NCC, due to Neoarchean intense tectono-thermal events in the NCC. Most Neoarchean BIFs in the NCC formed in island arc setting while BIFs in other areas (like Guyang) might form in deep mantle plume superimposed on island arc setting. There are mainly three types for BIF-hosted high-grade iron ore, primary-deposit type, later structure-hydrothermal superimposed type and ancient weathering crust type, but overall, only a small quantity of high-grade iron ore exist in the NCC and the third type, widespread in foreign countries, is rare in China. This article argues that comprehensive discriminant should take the greenstone belt development sequences into consideration when discussing the types of BIF iron deposits. Algoma-type BIFs often originate in the craton basement setting (greenstone belts) while Superior-type BIFs often form in marine sedimentary basins in the stable craton or in the passive continental margin. Large amount of geochemistry research results of BIFs in the NCC indicate that BIF iron ores lack Ce negative anomaly and their iron isotope characteristics are positive, which suggest that iron deposits formed in low-oxygen or anoxia environments, and the Eu positive anomaly may indicate that BIFs are hot water deposits. The possible mechanism may be that some elements such as Fe and Si are leached out from newly-formed mafic-ultramafic oceanic crust because of the convective circulation of seawater, and then they precipitate in the ocean floor due to changes of physicochemical conditions. The fluctuating eruption of ore-forming fluids may lead to the formation of banded structure of BIFs. However there are some problems needed to be further studied in detail such as material source, minerogenetic condition and mechanism of BIF iron deposits, causes of high-grade ore, reasons for lack of Superior-type BIF iron deposits in the NCC.
WOS关键词	SULFUR CYCLE ; KEY ISSUES ; EVOLUTION ; CONSTRAINTS ; GEOCHEMISTRY ; PROVINCE ; ISOTOPES ; CRUST ; AGE ; ORIGIN
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000312572600001
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84618]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhang LianChang
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 3.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Zhang LianChang,Zhai MingGuo,Wan YuSheng,et al. Study of the Precambrian BIF-iron deposits in the North China Craton: Progresses and questions[J]. ACTA PETROLOGICA SINICA,2012,28(11):3431-3445.
APA	Zhang LianChang.,Zhai MingGuo.,Wan YuSheng.,Guo JingHui.,Dai YanPei.,...&Liu Li.(2012).Study of the Precambrian BIF-iron deposits in the North China Craton: Progresses and questions.ACTA PETROLOGICA SINICA,28(11),3431-3445.
MLA	Zhang LianChang,et al."Study of the Precambrian BIF-iron deposits in the North China Craton: Progresses and questions".ACTA PETROLOGICA SINICA 28.11(2012):3431-3445.