Local structural markers of the Batouri gold-bearing shear zone in Southeast Cameroon

Document Type : Research Paper

Authors

1 The Department of Earth Sciences, Faculty of Sciences, University of Yaoundé 1, 812, Cameroon

2 Institute of Geological and Mining Research (IRGM), 4110 Nlongkak, Yaoundé, Cameroon

3 Geology Department, Faculty of Science, Minia University, 61519, El-Minia, Egypt

Abstract

The mining district of Batouri is located in the southeastern part of Cameroon and constitutes an integral part of the Adamaoua-Yadé domain of the Pan-African fold belt. This work aimed to highlight the structural and petrographic markers that characterize the auriferous shear zone. The investigations show that the rocks of the Batouri area suffered a ductile-brittle shear deformation in three directions (E-W, NE-SW, and NW-SE). These shear directions constitute the local extension of the Demza and the Balche shear zones of the Poli group, and the central Cameroon shear zone. Within these shear bands, the S n schistosity and tension cracks present a sigmoidal geometry, which is justified by a variation in the direction and dip of the schistosity planes and veins. This shear zone displays a finite local extension (NNW-SSE) generated by an ENE-WSW compression. Intense shearing is observed within gold- bearing monzogranites and syenogranites. The gold mineralization is controlled by three main vein directions (NNW-SSE, E-W and NE-SW), which are closely associated with silicification, sulfidation, and K-alteration of the host granitoids.

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Article Title [Persian]

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Abd El-Wahed, M., Zoheir, B., Pour, A.B., Kamh, S., 2021. Shear-related gold ores in the Wadi Hodein
Shear Belt, South Eastern Desert of Egypt: analysis of remote sensing, field and structural data.
Minerals, 11(5): 474.
Adam, M.M., Lv, X., Fathy, D., Rahman, A.R.A.A., Ali, A.A., Mohammed, A.S., Farahat, E.S., Sami,
M., 2022. Petrogenesis and tectonic implications of Tonian island arc volcanic rocks from the
Gabgaba Terrane in the Arabian-Nubian Shield (NE Sudan). Journal of Asian Earth Sciences, 223:
105006.
Ali, S., Abart, R., Sayyed, M.I., Hauzenberger, C.A., Sami, M., 2023. Petrogenesis of the Wadi El-Faliq
Gabbroic Intrusion in the Central Eastern Desert of Egypt: Implications for Neoproterozoic Post-
Collisional Magmatism Associated with the Najd Fault System. Minerals, 2023: 13, 10
Asaah, A.V., Zoheir, B., Lehmann, B., Frei, D., Burgess, R., Suh, C.E., 2015. Geochemistry and
geochronology of the~ 620 Ma gold-associated Batouri granitoids, Cameroon. International Geology
Review, 57(11-12): 1485-1509.
Bell, T.H., Johnson, S.E., 1989. porphyroblast inclusion trails: the key to orogenesis. Journal of
Metamorphic Geology, 7 (3): 279-310.
Benedicto, A., Plagnes, V., Vergély, P., Flotté, N., Schultz, R., 2008. Fault and fluid interaction in a
rifted margin: integrated study of calcite-sealed fault-related structures (southern Corinth margin).
Geological Society, London, Special Publications, 299(1): 257-275.
Castaing, C., Feybesse, J., Thiéblemont, D., Triboulet, C., Chevremont, P., 1994. Palaeogeographical
reconstructions of the Pan-African/Brasiliano orogen: closure of an oceanic domain or
intracontinental convergence between major blocks?. Precambrian Research, 69(1-4): 327-344.
206 Boukar et al.
Cloos, E., 1955. Experimental analysis of fracture patterns. Geological Society of America Bulletin,
66(3): 241-256.
Cornacchia, M., Dars, R., 1983. Un trait structural majeur du continent Africain; les lineaments
centrafricains du Cameroun au Golfe d'Aden. Bulletin de la Société géologique de France, 7(1): 101-
109.
Davis, G.H., Reynolds, S., Kluth, C., 2011. Structural geology of rocks and regions. Jhon Wiley & Sons.
Inc. New York.
Fabricio-Silva, W., Rosière, C.A., Bühn, B., 2019. The shear zone-related gold mineralization at the
Turmalina deposit, Quadrilátero Ferrífero, Brazil: Structural evolution and the two stages of
mineralization. Mineralium Deposita, 54(3): 347-368.
Jolly, R.J., Cosgrove, J.W., 2003. Geological evidence of patterns of fluid flow through fracture
networks: examination using random realizations and connectivity analysis. Geological Society,
London, Special Publications, 209(1): 177-186.
Kankeu, B., Greiling, R.O., Nzenti, J.P., Bassahak, J., Hell, J.V., 2012. Strain partitioning along the
Neoproterozoic Central Africa shear zone system: structures and magnetic fabrics (AMS) from the
Meiganga area, Cameroon. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen: 27-47.
Mukherjee, S., Biswas, R., 2014. Kinematics of horizontal simple shear zones of concentric arcs
(Taylor–Couette flow) with incompressible Newtonian rheology. International Journal of Earth
Sciences, 103(2): 597-602.
Ndonfack, K.I.A., Xie, Y., Goldfarb, R., Zhong, R., Qu, Y., 2021. Genesis and mineralization style of
gold occurrences of the Lower Lom Belt, Bétaré Oya district, eastern Cameroon. Ore Geology
Reviews, 139: 104586.
Ngako, V., Affaton, P., Nnange, J., Njanko, T., 2003. Pan-African tectonic evolution in central and
southern Cameroon: transpression and transtension during sinistral shear movements. Journal of
African Earth Sciences, 36(3): 207-214.
Ngako, V., Njonfang, E., Aka, F.T., Affaton, P., Nnange, J.M., 2006. The North–South Paleozoic to
Quaternary trend of alkaline magmatism from Niger–Nigeria to Cameroon: complex interaction
between hotspots and Precambrian faults. Journal of African Earth Sciences, 45(3): 241-256.
Ngako, V., Njonfang, E., 2018. Comment on “The Adamawa–Yade, a piece of Archaean crust in the
Neoproterozoic Central African orogenic belt (Bafia area, Cameroon)“, by Jacqueline Tchakounté et
al. [Precambrian Research 299 (2017) 210–229]. Precambrian Research, 305: 508-513.
Nguemhe Fils, S.C., Mimba, M.E., Nyeck, B., Nforba, M.T., Kankeu, B., Njandjock Nouck, P., Hell,
J.V., 2020. GIS-based spatial analysis of regional-scale structural controls on gold mineralization
along the Betare-Oya Shear Zone, Eastern Cameroon. Natural Resources Research, 29(6): 3457-
3477.
Njonfang, E., Ngako, V., Kwekam, M., Affaton, P., 2006. Les orthogneiss calco-alcalins de Foumban–
Bankim: témoins d'une zone interne de marge active panafricaine en cisaillement. Comptes Rendus
Geoscience, 338(9): 606-616.
Njonfang, E., Ngako, V., Moreau, C., Affaton, P., Diot, H., 2008. Restraining bends in high temperature
shear zones: the “Central Cameroon Shear Zone”, Central Africa. Journal of African Earth Sciences,
52(1-2): 9-20. Ramsay JG (1980) Shear Zone geometry: a review. Journal of structural geology, 2(1-
2): 83-99.
Ramsay, J.G., Graham, R.H., 1970. Strain variation in shear belts. Canadian Journal of Earth Sciences,
7(3): 786-813.
Seguem, N., Diondoh, M., Kepnamou, A. D., Mama, N., Sami, M., Alexandre, G. A., Emmanuel, E. G.,
2022. Petrography and Geochemistry of Baïbokoum-Touboro-Ngaoundaye Granitoids on the Chad-
Cameroon-RCA Borders (Adamawa-Yade Domain). Open Journal of Geology, 12(2): 136-155.
Sibson, R.H., 1977. Fault rocks and fault mechanisms. Journal of the Geological Society, 133(3):191-
213.
Tanko Njiosseu, E.L., Nzenti, J.P., Njanko, T., Kapajika, B., Nédélec, A., 2005. New U–Pb zircon ages
from Tonga (Cameroon): Coexisting Eburnean-Transamazonian (2.1 Ga) and Pan-African (0.6 Ga)
imprints. Comptes Rendus Geosciences, 337 : 551-562.
Tchakounté, J., Eglinger, A., Toteu, S.F., Zeh, A., Nkoumbou, C., Mvondo-Ondoa, J., Penaye, J., de
Wit, M., Barbey, P., 2017. The Adamawa-Yadé domain, a piece of Archaean crust in the
Neoproterozoic central African orogenic belt (Bafia area, Cameroon). Precambrian Research, 299:
Geopersia 2023, 13(1): 185-207 207
210-229.
Tiwari, S.K., Beniest, A., Biswal, T.K., 2020. Extension-driven brittle exhumation of the lower-middle
crustal rocks, a paleostress reconstruction of the Neoproterozoic Ambaji Granulite, NW India.
Journal of Asian Earth Sciences, 195: 104341.
Toteu, S., Van Schmus, W., Penaye, J., Michard, A., 2001. New U–Pb and Sm–Nd data from northcentral
Cameroon and its bearing on the pre-Pan African history of central Africa. Precambrian
Research, 108(1-2): 45-73.
Toteu, S.F., Penaye, J., Djomani, Y.P., 2004. Geodynamic evolution of the Pan-African belt in central
Africa with special reference to Cameroon. Canadian Journal of Earth Sciences, 41(1): 73-85.
Toteu, S.F., Yongue Fouateu, R., Penaye, J., Tchakounte, J., Seme Mouangue, A.C.,Van Schmus, W.R.,
Deloule, E., Stendal, H., 2006. U–Pb dating of plutonic rocks involved in the nappe tectonic in
southern Cameroon: consequence for the PanAfrican orogenic evolution of the central African fold
belt. Journal of African Earth Sciences, 44: 479–493.
Van Schmus, W.R., Oliveira, E.P., Da Silva Filho, A.F., Toteu, S.F., Penaye, J., Guimarães, I.P., 2008.
Proterozoic links between the Borborema province, NE Brazil, and the central African fold belt.
Geological Society, London, Special Publications, 294(1): 69-99.
Vishiti, A., Suh, C., Lehmann, B., Egbe, J., Shemang, E., 2015. Gold grade variation and particle
microchemistry in exploration pits of the Batouri gold district, SE Cameroon. Journal of African
Earth Sciences, 111: 1-13.
White S, Burrows SE., Carreras J., Shaw ND, Humphreys FJ., 1980. On mylonites in ductile shear
zones. Journal of Structural Geology, 2: 175-187.
Yannah, M., Suh, C.E., Mboudou, M.G.M., 2015. Quartz Veins Characteristics and Au Mineralization
Within the Batouri Au District, East Cameroon. Science Research, 3(4): 137149.