Geology
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Item Geology of Basement Complex rocks in Kabo area, Kano, Northwestern Nigeria: Insights into the Trends of Mineralization in the Region(INTERNATIONAL JOURNAL OF SCIENCE FOR GLOBAL SUSTAINABILITY, 2025-03) Lawal, M.; Mohammed, M. A.; Alalade, K. A.; Hamidu, H.; Shuaibu, A. M.; Yelwa, N. A.; Omanayin, Y. A.; Adeniyi, F. S.Nigeria is situated in a mobile zone separating older cratons of West Africa and Gabon, and underlain by nearly equal proportions of sedimentary and crystalline rocks. The crystalline basement rocks comprises three lithological groups (the Basement Complex, the Younger Granites and the Tertiary-Recent Volcanics) that were affected by Pan African (~550 Ma) thermo-tectonic events. The Basement Complex (Precambrian) encompasses gneisses- and migmatite-complex with schist belts, granites and minor charnokites and syenites with complex history and geochronology. In Kano (Kabo NE, Sheet 80 of Nigerian Geological Survey Agency maps) NW Nigeria, outcrops of these late Precambrian – lower Paleozeoic crystalline rocks are being mined of economic minerals. However, only a few studies exist on the geology of Kabo region. Therefore, this study describes the geology (lithology, composition, associated structures and field relationship) of rocks that characterize Kabo region, Kano and discuss trends of associated mineralization using field mapping and thin section petrography. Our data also includes high-resolution photographs of evidential geology of the area, parts of which are now defaced due to intense mining activities. Results showed that Kabo area is underlain by three rock groups: a migmatite-gneiss complex, an infolded schist belt (Younger Metasediments) and the Older Granites (porphyritic biotite granites, porphyroblastic biotite-rich gneiss and fine-medium grained granites). The porphyroblastic biotite-rich gneisses of the Older Granite division trend mainly in NE-SW and cut through the migmatite-gneiss complex; they exhibit preferred mineral alignment, suggesting that they are probably granitization products of the migmatite-gneisses, later metamorphosed and deformed. The granitized bodies are enriched in tourmaline that occur both in the NE-SW porphyroblastic rocks and the schist belt. The study thus serves as guide for investment decisions on solid mineral exploration in the area, and as a handbook for students of geology and tourists who now find Kano as a relatively safe geoheritage site. Keywords: Basement Complex, Northern Nigeria, KanoItem Field and Petrographic Studies of Basement Complex Rocks in Saigbe and Environs, North-Central, Nigeria(Nigerian Journal of Basic and Applied Sciences (NJBAS), 2023-06) Omanayin, Y. A.; Lawal, M.; Bolaji, I. B.; Muhammad, A.Geological mapping and petrographic studies of rocks provide useful information on texture and mineralogical composition of rocks which can be used in the exploration and exploitation of any associated mineralization. However, few regional studies have been conducted in Minna and environs. Here, preliminary field mapping and petrography of out crops in Saigbe environ were conducted to determine their identification, structural and mineralogical composition. Twenty-one rock samples were collected, eight of which were used for thin section analysis. Joint directions were measured and plotted on rose diagram. Results show that Saigbe is underlain by schist, amphibolite and granite with minor pegmatite intrusions. Joints, faults, fold and foliations constitute main structures. Joints in the schists trend NE-SW, while those in the granites trend NW-SE, suggesting different episodes of emplacement for both rocks. Petrography revealed that the schists comprised quartz, biotite, muscovite, plagioclase and opaque mineral, while the amphibolites are composed largely of quartz, hornblende, plagioclase feldspar and opaque minerals. The granites are composed of quartz, microcline, plagioclase feldspar, muscovite and opaque minerals. The pegmatite dykes in the granites comprised quartz, plagioclase feldspar, orthoclase feldspar, muscovite and gemstones, hence interpreted as product of residual melt. The pegmatites make interesting target for mineral exploration. Keywords: Older Granite, Basement Complex, Petrography, Pegmatites, Northern NigeriaItem Characterization of Pegmatites in Ogodo-Odobola Area of Idah Sheet 267NW, Central Nigeria(INTERNATIONAL JOURNAL OF SCIENCE FOR GLOBAL SUSTAINABILITY, 2023-07) Omanayin, Y. A.; Waziri, N. M.; Onoduku, U. S.; Alabi, A. A.The pegmatites of Ogodo-Odobola area around Ajaokuta, Central Nigeria belong to the pegmatite belt of Central Nigeria. A detailed geological mapping of the pegmatites and host rocks was conducted with the aim of understanding their mode of occurrence and field relationship and to assess their mineralization potentials. Twelve (12) representative samples of rocks were selected for petrographic analysis. The results show that the area is underlain by migmatite-gneiss, schist, with intrusions of granite and pegmatite. The pegmatites occur in tabular form with varying widths (2 centimetres – 6 metres) and lengths (12 – 200 metres). Principal joint direction is NNE-SSW which is believed to have influenced the pegmatite emplacement. Petrography of the representative rock samples revealed an average mineralogical composition of biotite (23.90%), microcline (22.15%), hornblende (15.05%), quartz (10.65%), plagioclase (10.35%), muscovite (8.00%), myrmekite (0.20%), and opaque and accessory minerals (9.70%). The pegmatites were found to be dominated by microcline and plagioclase feldspars, and then muscovite, biotite, and accessory and opaque minerals. The pegmatite of the Ogodo-Odobola area is worth probing as the results have shown prospect for possible economic minerals. Keywords: Mineralization, Basement Complex, Structural Features, Petrography, Ajaokuta