摘要
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 incon-sistent 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.
The Oban Basement Massif of southeastern Nigeria is composed of metamorphosed rocks including phyllites, schists, gneisses and arnphibolites 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 axe 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.
