Mineralization of pegmatites in parts of the Oban Massif, Southeastern Nigeria: A preliminary analysis

Abstract

The Oban Basement Massif of southeastern Nigeria is composed of metamorphosed rocks including phyllites, schists, gneisses and amphibolites cut by pegmatitic dykes of varying length and thickness, which intruded the metamorphic rocks. Preliminary geochemical study and analysis of these pegmatites from western Oban Massif at Uyanga, Akwa Ibami, Iwuru I, Iwuru II and Igbofia showed that the pegmatites are highly albitized. This is inconsistent with earlier postulations that the pegmatites in this part of Nigeria are barren. Indices of fractionation such as Ba/Rb, K/Rb, Na/K, K/Cs, K/Ba reveal that the pegmatites are mineralized and different discrimination plots show that they are enriched in Li, Be, Sn, Ba, Ta, Ni, Cs, Sn and Zn. Rare metal indicative elements such as Ta, Nb, Rb, Cs, and Sn are enriched in the pegmatites, confirming that the pegmatites are mineralized.

New Insights into Pre-to-Post Ediacaran Zircon Fingerprinting of the Mamfe PanAfrican Basement, SW Cameroon: A Possible Link with Rocks in SE Nigeria and the Borborema Province of NE Brazil

“…The Kibarian was followed by ages ranging from 900-450 Ma representing the imprint of the PanAfrican orogenic events (around 600 ± 70 Ma, [86]) that gave rise to migmatite, gneisses, and older granite intrusions [84]. The PanAfrican basements in SE Nigeria are composed of gneisses, phyllites, schists, amphibolites migmatites, and granites [87][88][89]. Basement rocks in this complex were invaded by numerous intrusive bodies ranging from massive to thin dyke-like bodies [88].…”

“…Basement rocks in this complex were invaded by numerous intrusive bodies ranging from massive to thin dyke-like bodies [88]. These intrusive rocks include granites, dolerites, pegmatites, syenites, diorites, granodiorites, and charnockites [89]. The metamorphic basement rocks in the Oban area of SE Nigeria, which underwent polymetamorphism, with the grade ranging from medium greenschist facies in phyllites and schists to uppermost amphibolite facies in the kyanite-sillimanite schists, garnet sillimanite schists, and migmatic gneisses [90].…”

Tin Mineralisation in Nigeria: A Review

“…Notable mineralized pegmatites are found in Ijero, Sepeteri, Aramoko, Ife-Ilesha, Ikoro, Osu, Igbeti, Oro, Oke-Ogun, Komu, Egbe, Akata, Wamba-Jema'a, Keffi, Akwanga, Gwon Gwon, and Jos Plateau, all occurring within the Nigerian mineralized pegmatite belt. A few occurrences of poorlow grade tin-bearing pegmatites have also been found outside the pegmatite belt in the Obudu and Oban massifs in southeastern Nigeria [29,33,[37][38][39][40]. The mineralized pegmatites have yielded about 5% of the total cassiterite produced in Nigeria [25,41].…”