Bulk geochemistry,Rb-Sr,Sm-Nd,and stable O-H isotope systematics of the Metzimevin high-grade iron ore deposit,Mbalam iron ore district,southern Cameroon

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外文标题：Bulk geochemistry,Rb-Sr,Sm-Nd,and stable O-H isotope systematics of the Metzimevin high-grade iron ore deposit,Mbalam iron ore district,southern Cameroon

外文摘要：Bulk geochemistry,Sr,Nd,and O-H isotope systematics are reported for the first time on banded iron formation(BIF)-hosted high-grade iron ore at the north-western segment of Congo Craton(CC).Located in Mbalam iron ore district,Southern Cameroon,Metzimevin iron ore deposit is a hematite-magnetite BIF system,dominated by SiO2+Fe2O3(97.1 to 99.84 wt％),with low concentrations of clastic elements e.g.,Al2O3,TiO2,and HFSE,depicting a nearly pure chemical precipitate.The REE+Y signature of the iron deposit displays strong positive Eu anomaly,strong negative Ce anomaly,and chondritic to superchondritic Y/Ho ratios,suggestive of formation by mixed seawater-high temperature hydrothermal fluids in oxidising environment.The 87Sr/86Sr ratios of the BIF are higher than the maximum 87Sr/86Sr evolution curves for all Archean reservoirs(bulk silicate earth,Archean crust and Archean seawater),indicat-ing involvement of continentally-derived components during BIF formation and alteration.The εNd(t)(+2.26 to+3.77)and Nd model age indicate that chemical constituents for the BIF were derived from undifferentiated crustal source,between 3.002 and 2.88 Ga.The variable and diverse O and H isotope data(-1.9‰ to 17.3‰ and-57‰ to 136‰respectively)indicate that the Metzimevin iron ore formed initially from magmatic plumes and later enriched by mag-matic-metamorphic-modified meteoric fluids.Mass balance calculations indicate mineralisation by combined leaching and precipitation,with an average iron enrichment factor of＞2.67 and SiO2 depletion factor of＞0.99.This is associ-ated with an overall volume reduction of 28.27％,reflecting net leaching and volume collapse of the BIF protholith.

外文关键词：

Bulk geochemistryRb-SrSm-NdMitzimevinHigh-grade iron ore

作者：

Samndong Cyril Tufoin、Cheo Emmanuel Suh、Tabod Charles Tabod、George Lemewihbwen Ngiamte

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作者单位：

Department of Geology,Mining and Environmental Science,The University of Bamenda,B.P.39,Bambili,North West Region,Cameroon

Economic Geology Unit,Department of Geology,University of Buea,P.O.63,Buea,South West Region,Cameroon

Department of Physics,Faculty of Science,The University of Bamenda,B.P.39,Bambili,North West Region,Cameroon

Department of Geology,Pan-African University Life and Earth Sciences Institute(PAULESI),University of Ibadan,Ibadan,Nigeria

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关键词：

Bulk geochemistry Rb-Sr Sm-Nd Mitzimevin High-grade iron ore

出版年：

2024

DOI：

10.1007/s11631-023-00667-x

地球化学学报(英文版)

中国科学院地球化学研究所

地球化学学报(英文版)

影响因子：0.33

ISSN：2096-0956

年,卷(期)：2024.43(4)