PETROGENESIS, TECTONIC SETTING AND MINERAL POTENTIAL OF IGNEOUS ROCKS FROM THE GAMPU AREA AND ENVIRONS, ZING, NORTHEASTERN NIGERIA: CONSTRAINTS FROM FIELD GEOLOGY AND GEOCHEMISTRY
The Gampu area of Zing, northeastern Nigeria, located approximately between 8°43′–8°49′N and 11°35′–11°45′E, forms part of the northern Adamawa Massif and exposes a diverse assemblage of Precambrian basement and intrusive igneous rocks. The geology tectonic setting and mineral potential of Gampu and its environs is poorly constrained. This study aims to investigate the petrogenesis, tectonic setting and mineral potential of the igneous rocks in the area using integrated field geology, petrography and whole-rock major- and trace-element geochemistry. Geological mapping identified gneisses, granites, granodiorites, tonalites, quartz syenites, quartz monzonites and minor mafic intrusions, including doleritic dykes. Petrographic observations reveal mineral assemblages dominated by quartz, plagioclase, alkali feldspar, biotite and amphibole, with accessory phases including zircon, allanite, titanite, apatite and opaque minerals. Whole-rock geochemical analysis reveals intermediate to felsic compositions, with SiO₂ contents ranging from 49.1 to 70.2 wt.% in the analysed igneous rocks. Major-element classification and alumina-saturation characteristics indicate diverse granitoid compositions ranging from metaluminous to peraluminous. Harker variation trends indicate that fractional crystallization, involving the progressive removal of mafic minerals, feldspar and accessory phases, played an important role in magma evolution, although the compositional diversity suggests contributions from more than one parental magma. The granites and granodiorites exhibit geochemical characteristics compatible with crustally influenced, syn-collisional magmatism, whereas the tonalites, quartz monzonites and quartz syenites show affinities with late- to post-collisional magmatism. The latter association is interpreted to reflect mantle-influenced magmatism followed by fractional crystallization and variable interaction with continental crust. The coexistence of contrasting magmatic affinities suggests that the Gampu area records multiple stages of Pan-African tectono-magmatic evolution, from crustal melting and syn-collisional granitoid emplacement to late- and post-collisional magmatism and progressive differentiation. Trace-element enrichment, particularly in Rb, Zr, Y and Nb, indicates substantial magmatic differentiation and suggests potential for rare-metal mineralization. The anomalously high Nb and Ta concentrations recorded in sample GM01 warrant further analytical and mineralogical verification, while the elevated Cr and Ni contents of the dolerite indicate a mafic component that merits further investigation. Overall, the Gampu area represents a compositionally and tectonically diverse magmatic domain whose mineralization potential is closely related to magmatic differentiation and late-stage tectono-magmatic processes. Further geochronological, isotopic and mineral-chemical investigations are recommended to establish the timing, magma sources and economic significance of the observed geochemical anomalies.
Authors : Ahmed, H.A., Anthony, O.I., Haruna, I.V., Kaigama, U., Abdallsamed, M.I.M., Halilu, M., Aminu, N.I., Umar, M.F., Yahaya, A., Umar, Z. and Amodu, A.
Category : Open Access Volume (Issue) : 12(1) Date Uploaded : 26th September 2026