The characterization of the relationships between
mineralization and hydrothermal alteration is an essential element in
understanding gold deposits. In south-west Burkina Faso, the Napélépéra
mineralisation, the mobility of chemical elements and alteration-mineralization
relationships were studied by means of selected core drilling and geochemical
analyses using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and
ICP-AES (Inductively coupled plasma atomic emission spectroscopy). The
mineralised granodiorite is grey porphyroid with quartz, plagioclase, biotite and amphibole. It
is metaluminous and located in the tholeiitic series. The Na2O + CaO versus Fe2O3 + MgO
alteration diagram divides the samples according to alteration dominance.
Chloritisation and carbonation are the main alterations. There is a
relationship between gold mineralisation at Napélépéra and alteration, and the
paragenesis of gold + pyrite ± carbonate ± silica ± sericite is the main
characteristic. Carbonation is the result of fluid input in the shear corridor
of the mineralised zone. The mass balance of comparative metals in the proximal
and distal zones of the mineralisation shows the absence of metals, while As,
Hg, Ag and Bi are strongly enriched from the distal zone to the mineralised
zone. The oxides associated with the mineralisation are mainly NaO, SrO and CaO.
References
[1]
Abd El Monsef, M., Slobodník, M. and Salem, I.A. (2018) Hydrothermal Evolution of Granitoid-Hosted Gold Mineralization in Gidami Area: An Example for Orogenic-Gold Deposits in Egypt. Journal of African Earth Sciences, 146, 132-149.
https://doi.org/10.1016/j.jafrearsci.2018.04.007
[2]
Ada, K., Gampini, S.E., Naba, S., Marquis, P., Lompo, M., Wenmenga, U., Traoré, S.A. and Ilboudo, H. (2011) Le Gite Aurifere De Djarkadougou Dans La Ceinture De Roches Vertes De Hounde (Burkina Faso-Afrique De L’Ouest): Contexte Lithologique Et Structural. Journal des Sciences et Technologies, 9, 49-64.
[3]
Eilu, P. and Mikucki, E.J. (1998) Alteration and Primary Geochemical Dispersion Associated with the Bulletin Lode-Gold Deposit, Wiluna, Western Australia. Journal of Geochemical Exploration, 63, 73-103.
https://doi.org/10.1016/S0375-6742(98)00016-8
[4]
Schwartz, M.O. and Melcher, F. (2003) The Perkoa Zinc Deposit, Burkina Faso. Economic Geology, 98, 1463-1485. https://doi.org/10.2113/gsecongeo.98.7.1463
[5]
Ouattara, G., Saga, S., Ouedraogo, A., Bamba, O., Ouattara, G., Gampine, E. and Sawadogo, S. (2016) Caractérisations structurales des gites aurifères du corridor de Bouboulou-Bouda au Burkina Faso, Afrique de l’Ouest. Afrique Science, 12, 89-104.
[6]
Sawadogo, S., Naba, S., Ilboudo, H., Traoré, A.S., Nakolendoussé, S. and Lompo, M. (2018) The Belahourou granite pluton (Djibo greenstone belt, Burkina Faso): Emplacement Mechanism and Implication for Gold Mineralization along a Shear Zone. Journal of African Earth Sciences, 148, 59-68.
https://doi.org/10.1016/j.jafrearsci.2018.04.009
[7]
Baratoux, L., Metelka, V., Naba, S., Ouiya, P., Siebenaller, L., Jessell, M.W., Naré, A., Salvi, S., Béziat, D. and Franceschi, G. (2015) Tectonic Evolution of the Gaoua Region, Burkina Faso: Implications for Mineralization. Journal of African Earth Sciences, 112, 419-439. https://doi.org/10.1016/j.jafrearsci.2015.10.004
[8]
Ouedraogo, T., Sawadogo, S., Kiéma, B. and Naba S. (2022) La minéralisation aurifère de Napélépéra, SW Burkina Faso, Afrique de l’Ouest: Mise en place dans une zone de cisaillement tardi-orogénique éburnéenne. Afrique Science, 20, 81-92.
[9]
Ouiya, P., Siebenaller, L., Salvi, S., Béziat, D., Naba, S., Baratoux, L., Naré, A. and Franceschi, G. (2015) The Nassara Gold Prospect, Gaoua District, Southwestern Burkina Faso. Ore Geology Reviews, 78, 623-630.
https://doi.org/10.1016/j.oregeorev.2015.11.026
[10]
Castaing, C., Billa, M., Milesi, J.P., Thieblemont, D., Le Mentour, J., Egal, E., Donzeau, M., Guerrot, C., Cocherie, A., Chevremont, P., Tegyey, M., Itard, Y., Zida, B., Ouedraogo, I., Kote, S., Kabore, B.E., Ouedraogo, C., Ki, J.C. and Zunino, C. (2003) Notice explicative de la carte géologique et minière du Burkina Faso a 1/1,000,000. BRGM BUMIGEB, 147.
[11]
Baratoux, L., Metelka, V., Naba, S., Jessell, M.W., Gregoire, M. and Ganne, J. (2011) Juvenile Paleoproterozoic Crust Evolution during the Eburnean Orogeny (～2.2-2.0 Ga), Western Burkina Faso. Precambrian Research, 191, 18-45.
https://doi.org/10.1016/j.precamres.2011.08.010
[12]
Gasquet, D., Barbey, P., Adou, M. and Paquette, J.L. (2003) Structure Sr-Nd Isotope Geochemistry and Zircon U-Pb Geochronology of the Granitoids of the Dabakala Area (Ivory Coast): Evidence for a 2.3 Ga Crustal Growth Event in the Palaeoproterozoic of West Africa? Precambrian Research, 127, 329-354.
https://doi.org/10.1016/S0301-9268(03)00209-2
[13]
Kiema (2021) Mémoire de master université Joseph KI-ZERBO.
[14]
H&S Consultants Pty Ltd. (2019) NI 43-101 Technical Report Mineral Resource Estimates of the Doropo Project Cote d’Ivoire. 97.
[15]
Cox, K.G., Bell, J.D. and Pankhurst, R.J. (1979) The Interpretation of Igneous Rocks. George Allen and Unwin, London.
[16]
Peccerillo, A. and Taylor Sr. (1976) Geochemistry of Eocene Calc-Alkaline Volcanic Rocks from the Kastamonu Area, Northern Turkey. Contributions to Mineralogy and Petrology, 58, 63-81. https://doi.org/10.1007/BF00384745
[17]
Villaseca, C., Barbero, L. and Rogers, G. (1998) Crustal Origin of Hercynian peraluminous Granitic Batholiths of Central Spain: Petrological, Geochemical and Isotopic (Sr, Nd) Constraints. Lithos, 3, 55-79.
https://doi.org/10.1016/S0024-4937(98)00002-4
[18]
Large, R.R., Gemmell, J.B., Paulick, H. and Huston, D.L. (2001) The Alteration Box Plot: A Simple Approach to Understanding the Relationships between Alteration Mineralogy and Lithogeochemistry Associated with VHMS Deposits. Economic Geology, 96, 957-971. https://doi.org/10.2113/gsecongeo.96.5.957
[19]
Lang, J.R. and Baker, T. (2001) Intrusion-Related Gold Systems: The Present Level of Understanding. Mineralium Deposita, 36, 477-489.
https://doi.org/10.1007/s001260100184
[20]
Thomson, J.F.H., Sillitoe, R.H., Baker, T., Lang, J.R. and Mortensen, J.K. (1999) Intrusion Related Gold Deposits Associated with Tungsten Provinces. Mineralium Deposita, 34, 323-334. https://doi.org/10.1007/s001260050207
[21]
Feng, X., Amponsah, P.O., Martin, R., Ganne, J. and Jessell, M.W. (2015) Example of North-Western Ghana. Precambrian Research, 274, 161-179.
[22]
Ofori, P., Salvi, S., Béziat, D., Siebenaller, L., Baratoux, L. and Jessell, M.W. (2015) Geology and Geochemistry of the Shear-Hosted Julie Gold Deposit, NW Ghana. Journal of African Earth Sciences, 112, 505-523.
[23]
Allibone, A., Hayden, P., Cameron, G. and Duku, F. (2004) Paleoproterozoic Gold Deposits Hosted by Albite- and Carbonate-Altered Tonalite in the Chirano District, Ghana, West Africa. Economic Geology, 99, 479-497.
https://doi.org/10.2113/gsecongeo.99.3.479
