Petrogenetic characterization of the host rocks of the Sanaga iron ore prospect,southern Cameroon  

作　　者：Tasin Godlove Bafon Anthony Temidayo Bolarinwa Cheo Emmanuel Suh Temesgen Oljira Bekele Ayele Bedada Gilles Nyuyki Ngoran Kevin Ijunghi Ateh Boris Martial Keuko Djoumbissie Cho Terence Ngang 

机构地区：[1]Department of Geology,Pan African University Life and Earth Science Institute,University of Ibadan,Ibadan,Nigeria [2]Department of Geology,Mining and Environmental Science,University of Bamenda,P.O.Box 39,Bambili,Cameroon [3]Explorers 33 Consulting Group Sarl,P.O.Box 6666,Yaounde,Cameroon [4]Department of Earth Sciences,Faculty of Science,University of Yaounde I,P.O.Box 812,Yaounde,Cameroon

出　　处：《Acta Geochimica》2023年第2期195-220,共26页地球化学学报（英文）

摘　　要：The Sanaga iron ore prospect is a recent discovery in the Nyong Series with a resource estimated at 82.9 Mt at 32.1%Fe and whose origin remains debatable.The mineralization occurs as NE-SW oriented discontinuous lenticular bodies of magnetite-bearing pyroxenegneisses(MPG)hosted by ortho-derived gneisses.Rare amphibolites are observed.The MPG mineral assemblage consists of quartz-magnetite-orthopyroxene-garnet-tremolite/actinolite exhibiting a granoblastic texture,which is characteristic of granulite facies metamorphism.The granodioritic gneisses show compositional features of the tonalite-trondhjemite-granodiorite association.Their trace and REE element geochemistry indicate their protolith melt resulted from the partial melting of a subducted oceanic slab,with interaction with the overlying mantle wedge during ascent.The amphibolites show enrichment in LILE with negative Ta–Nb and Zr–Hf indicating arc-related magmas generated by partial melting of a sub-continental lithospheric mantle source with metasomatism by subduction-related fluids.The MPG exhibits oxidation-exsolution features characterized by ilmenite lamellae,with hematite fracture-fillinginmagnetite,andlacksfeatures characteristic of typical BIF such as LREE depletion relative to HREE,positive Eu,La,and Y anomalies.Based on the results of this study,we interpret the Sanaga MPG as a possible skarn-type mineralization formed by the metamorphism/metasomatism of a possible BIF protolith.The results of this study compare with similar magnetite-rich mineralization in the Sa o Francisco craton in northeastern Brazil and enhance the correlation of pre-drift reconstructions of the Sa o Francisco–Congo Cratons.

关 键 词：Magnetite-pyroxene-gneiss METASOMATISM Ilmenite exsolution Hematite fracture-filling Skarn type mineralization Nyong Series 

分 类 号：P618.31[天文地球—矿床学]