Deformation, Alteration and Geochemical Footprint of a Gold-Bearing Shear Zone in Metagranitoid and Metasediment, East Cameroon Goldfield — Oak Academic Publishing
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Deformation, Alteration and Geochemical Footprint of a Gold-Bearing Shear Zone in Metagranitoid and Metasediment, East Cameroon Goldfield
Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
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Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
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Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
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Department of Civil Engineering, The University Institute of Technology (IUT), University of Douala, Douala, Cameroon
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Department of Mining and Mineral Engineering, National Higher Polytechnic Institute, University of Bamenda, Bambili, Northwest Region, Cameroon
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Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Palapye, Botswana
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Department of Mining and Mineral Engineering, National Higher Polytechnic Institute, University of Bamenda, Bambili, Northwest Region, Cameroon
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Economic Geology Unit, Department of Geology, University of Buea, Buea, Cameroon
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Department of Geology, Pan African University Life and Earth Sciences Institute (PAULESI), University of Ibadan, Ibadan, Nigeria
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Technology and Applied Sciences Laboratory (TASL), University of Douala, Douala, Littoral Region, Cameroon
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Ore Treatment Laboratory, Institute of Geological and Mining Research (IRGM), Yaoundé, Nlongkak, Cameroon
1 Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
2 Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
3 Department of Geology, Mining and Environmental Science, The University of Bamenda, Bambili, Northwest Region, Cameroon
4 Department of Civil Engineering, The University Institute of Technology (IUT), University of Douala, Douala, Cameroon
5 Department of Mining and Mineral Engineering, National Higher Polytechnic Institute, University of Bamenda, Bambili, Northwest Region, Cameroon
6 Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Palapye, Botswana
7 Department of Mining and Mineral Engineering, National Higher Polytechnic Institute, University of Bamenda, Bambili, Northwest Region, Cameroon
8 Economic Geology Unit, Department of Geology, University of Buea, Buea, Cameroon
9 Department of Geology, Pan African University Life and Earth Sciences Institute (PAULESI), University of Ibadan, Ibadan, Nigeria
10 Technology and Applied Sciences Laboratory (TASL), University of Douala, Douala, Littoral Region, Cameroon
11 Ore Treatment Laboratory, Institute of Geological and Mining Research (IRGM), Yaoundé, Nlongkak, Cameroon
The Gankoumbol-Djouzami-Beka (GDB) area investigated in this study is part of the Central Cameroon Shear Zone (CCSZ) which is a network of anastomosing NE-SW-trending brittle-ductile mega shear. Primary gold mineralization in the area is restricted to secondary structures in the hydrothermally altered metagranitoids and metasediments pointing to a link between deformation, fluid flow and attendant mineral alteration synchronous with gold precipitation. Here, we document the spectrum of fault rocks that adorn the shear zone at the GDB area, ranging from ultramylonite/mylonite at the center of the shear zone that grades outwards through protomylonite to cataclasite at the margins. Shear sense indicators point to sinistral shear with a dominant prolate-type strain ellipsoid. The metagranitoid is subalkaline, with fault rocks characterized by alterations such as K-feldspar alteration, silicification, sericitization and sulphidation which affects the geochemistry of this altered assemblage. The least altered metagranitoid and fault rocks samples show LREE enrichment, depletion in HREE and a negative Eu anomaly depicting plagioclase fractionation over the various alteration categories. On the multielement variation plots, positive Rb, K, Sm, Pb, and Th anomalies and negative Nb, Sr, Ba, Ti and Zr anomalies are observed, resulting from hydrothermal alteration for the fault rocks. Gold (up to 1.8 g/t) mineralization is associated with sericitization, silicification and sulphidation. Hydrothermal alteration in fault rocks results to enrichment Mn, Cu, S, Au, Te, Fe, Bi, Ba, Mo, Mg, and depletion in Nb, Sn, As, Sb and Ga. Au-S-Cu-Mn-Te-Fe-Mo-Bi metal association constitutes a pathfinder element class reflecting gold mineralization contemporaneous with sulphidation.
KeywordsAlterationDeformationGoldCameroon
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