GEOLOGY, GEOCHEMISTRY AND RARE METAL POTENTIAL OF SOME PEGMATITES IN MAKARFI AREA, PART OF ZARIA SHEET 102 NE, NORTH CENTRAL BASEMENT COMPLEX OF NIGERIA
GEOLOGY, GEOCHEMISTRY AND RARE METAL POTENTIAL OF SOME PEGMATITES IN MAKARFI AREA, PART OF ZARIA SHEET 102 NE, NORTH CENTRAL BASEMENT COMPLEX OF NIGERIA
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Date
2018-09
Authors
AMINU, Raliya Hayatu
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Abstract
Geological mapping of Makarfi area on a scale of 1:50,000, petrographic and geochemical studies of selected rocks and mineral samples were carried out in order to unravel the evolutionary history and rare metal mineralization potential of the pegmatites in the area. The area is underlain by gneisses, granites and pegmatites. The granite suites vary in texture and mineralogy and comprise of; porphyritic hornblende-biotite granite, coarse grained biotite granite, medium grained biotite granite and medium grained muscovite granite. A total of 15 samples comprising seven (7) host rocks and eight (8) minerals were analysed for major, trace and REE using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using litho-4 and peroxide fusion techniques. The results obtained revealed that the gneisses, which include migmatitic gneiss, biotite gneiss and granitic gneiss are paragneisses, metaluminous with tholeiitic affinity. The granites are peraluminous (A/CNK>1) and calc-alkaline. The granite suites had undergone changes from a more primitive hornblende-biotite I-type variety to a more fractionated muscovite bearing S-type variety. The pegmatites are peraluminous, and the high Li-Cs-Ta contents of its minerals suggests that they belong to the LCT petrogenetic family, rare element class, while the high contents of Li, Rb, Cs, Be, Ga, Sn and Ta places the group under the beryl subtype. A genetic linkage between the granites and pegmatites was confirmed by their K/Rb, K/Ba and Rb/Sr ratios. The pegmatites represent the last stage fraction of liquid remaining after extensive fractional crystallization of granitic magma. Chemical data shows there is enrichment in Li, Rb, Cs, Ta, Sn, Nb and Ga during the differenciation and evolution of the pegmatites. The rare metal mineralization of the pegmatites were evaluated using K/Rb versus Rb, K/Rb versus Cs, Ta versus Cs, Ta versus K/Cs and Ta Versus Ga plots, and they were found to be comparable to other mineralized pegmatites of Nigeria but lower than the highly mineralized Tanco pegmatites. It is hereby proposed that the pegmatites differenciated from the granitic magma through magmatic and post magmatic differenciation processes and were then injected into the weak zones of the gneisses and granites.
Description
A THESIS SUBMITTED TO THE DEPARTMENT OF GEOLOGY, AHMADU BELLO UNIVERSITY ZARIA, IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE IN GEOLOGY (MINERAL EXPLORATION)
Keywords
GEOLOGY,, GEOCHEMISTRY,, METAL POTENTIAL,, PEGMATITES,, MAKARFI AREA,, ZARIA,, SHEET 102 NE,, NORTH CENTRAL,, BASEMENT COMPLEX,, NIGERIA,