Yıl 2021, Cilt 3 , Sayı 1, Sayfalar 61 - 69 2020-12-15

Geochemical Characterization and Rare-Metals (Ta-Nb) Mineralization Potentials of Pegmatites Around Lokoja, Central Nigeria

Daniel Imariabe OMORUYI [1] , Ebo Gabriel IMEOKPARIA [2]


Five pegmatite dykes in suburbs of Lokoja area, central Nigeria are studied using field, petrographical and geochemical data to characterize and determine the rare-metals (Ta-Nb) mineralization attributes. The pegmatites which occur as near-vertical, large veins and dykes are hosted by migmatitic biotite gneiss. The pegmatites consist of quartz, feldspar, muscovite with rare biotite, occasional beryl and some minor/accessory apatite and zircon. Composite whole-rock samples were analysed for major, trace and rare earth elements using X-Ray Fluorescence Spectrometer (XRF) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The results reveal the pegmatites are considerably siliceous with SiO2 values of 69.00% to 74.60%. Al2O3 values are relatively moderate (14.80% to 19.60%). Na2O and K2O abundances are low with ranges of 2.32% – 5.93%, 1.22% – 11.00% respectively. MgO abundances are generally low (0.03 – 0.07%). Fe203 values are also low; ranging from 0.31% to 1.16%. Alumina Saturation Index (A/CNK) computation with values ranging from 1.40 to 3.06 indicates the pegmatites are peraluminous. Trace and rare-earth elements results show Bakunba location pegmatite is mineralised (Nb: 571.86ppm, Ta: 180ppm) and compare favourably with other mineralised pegmatites in Nigeria; while Ganaja-2 location (Nb: 100.37ppm, Ta: 26.6ppm) are moderately mineralised. Nb-Ta values of Shagari location (33.14ppm; 2.7ppm), Ganaja-1 location (12.6ppm; 3.6ppm) and Crusher location (0.91ppm; 0.2ppm) show they are barren. Various variation plot diagrams, such as Kb/Rb vs Cs, K/Rb vs Rb, also show mineralization status of these pegmatite bodies as compared with some local and foreign pegmatites. Plots of Zr vs SiO2, Rb vs Y+Nb and Rb vs Sr indicate the pegmatites are magmatic, from within plate granites and in crustal thickness of more than 30 km during the time of emplacement.
Pegmatite, Rare metals mineralization, Trace elements, Niobium, Tantalum
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Birincil Dil en
Konular Yerbilimleri, Ortak Disiplinler
Bölüm Research Article
Yazarlar

Orcid: 0000-0002-0803-3945
Yazar: Daniel Imariabe OMORUYI
Kurum: Department of Geology, University of Benin
Ülke: Nigeria


Yazar: Ebo Gabriel IMEOKPARIA
Kurum: Department of Earth Sciences, Federal University of Petroleum Resources
Ülke: Nigeria


Tarihler

Yayımlanma Tarihi : 15 Aralık 2020

AMA Omoruyı D , Imeokparıa E . Geochemical Characterization and Rare-Metals (Ta-Nb) Mineralization Potentials of Pegmatites Around Lokoja, Central Nigeria. IJESKA. 2020; 3(1): 61-69.

Makalenin Yazarları
Daniel Imariabe OMORUYI [1]
Ebo Gabriel IMEOKPARIA [2]