Publications scientifiques
Marvine Nzepang Tankwa
Autres affiliations : University of Ibadan · Pan-Atlantic University
Landry Soh Tamehe
Autres affiliations : Central South University
Brice Kamguia Woguia
Arnold Steven Motto Mbita
Jean Paul Nzenti
Olugbenga Okunlola
Autres affiliations : Pan-Atlantic University
Evine Laure Tanko Njiosseu
International Geology Review
The Kelle Bidjoka Iron Formations (IFs) occur at the northmost margin of the Neoarchean to Paleoproterozoic Nyong group greenstone belts in SW Cameroon. This contribution presents for the first time the petrographical, geochemical, and geochronological data of the Kelle Bidjoka IFs and associated metaigneous (metatonalite) and metasedimentary (pyroxene gneiss) rocks. The studied IFs form a thin unit of 3.21 m thick and comprise magnetite pyroxene gneiss, garnet-bearing magnetite pyroxene gneiss, pyroxene BIFs, and grunerite BIFs. Petrographic studies have revealed mineral assemblages indicating retrograde amphibolite facies metamorphism. Magnetite pyroxene gneiss and pyroxene BIFs show signatures of both seawater and hydrothermal fluids, with magnetite pyroxene gneiss deposited closer to the vent source. In contrast, garnet-bearing magnetite pyroxene gneiss and grunerite BIFs are devoid of hydrothermal characteristics and show significant crustal contamination. The lack of Ce anomaly in most samples indicates anoxic to suboxic conditions during their deposition. The geochemical characteristics of the associated metaigneous and metasedimentary rocks indicate that Kelle Bidjoka IFs were deposited in a submarine volcanic arc environment, similar to the Algoma-type BIFs. Detrital zircon LA-ICP-MS U-Pb dating suggests that the Kelle Bidjoka BIFs were deposited during early Paleoproterozoic (ca. 2423 Ma) and were metamorphosed up to granulite facies during the Eburnean/Transamozian (ca. 2050 Ma) orogeny.
