IJG  Vol.4 No.10 , December 2013
Gold Behavior in Weathering Products of Quartz Vein in Mintom Area South Cameroon (Central Africa)

Gold mineralization in Mintom area, south Cameroon was studied in a tropical forest setting using X-ray diffraction, inductively coupled plasma-atomic emission spectrometry (ICP/AES) and inductively coupled plasma-mass spectrometry (ICP/MS) respectively for the mineralogical and chemical data. The mineralization occurs in quartz veins in the archean Ntem complex of the vast Congo Craton in Central Africa. Gold distribution patterns were vertically studied in the different horizons of the weathering profile and in the different grain-size fractions of the materials sampled in the pit on down slope of the interfluve where the mineralization exists. The weathering profile consists of an upper, thin loose sandy-clayey horizon (P6) covered by a light humic horizon, a nodular horizon with lateritic nodules or blocks (P5), a gravel horizon (P4), a thin spotted horizon (P3) and a saprolite (P2) up to 1.4 m thick. The specific geochemical signature of the bedrock is not recognized in each horizon of the weathering profile. Some groups of elements, e.g., high SiO2 and low REE characterize quartz vein while Cr-Ni characterizes a basic rock like gabbro. The residual gold is concentrated at the base of weathering profile. Its concentration increases from the saprolite up to the gravel horizon and decreases in the surface horizons. However, the evolution of visible Au distribution is not the same for all grain-size fractions: 1) in the finest fraction, the Au content is only regular in spotted and gravel horizons; 2) in the medium size fractions, the Au is in high content and greatly decreases from saprolite up to the spotted horizon and disappears in the upper horizons; 3) in the coarsest fraction, Au content is found in the saprolite and the maximum Au content of the weathering profile is found in this layer just above the mineralized quartz vein. This observation shows that the Mintom residual gold comes from the quartz vein.

Cite this paper
A. Mbenoun, G. Ngon, E. Bayiga, R. Fouateu and P. Bilong, "Gold Behavior in Weathering Products of Quartz Vein in Mintom Area South Cameroon (Central Africa)," International Journal of Geosciences, Vol. 4 No. 10, 2013, pp. 1401-1410. doi: 10.4236/ijg.2013.410137.
[1]   A. W. Mann, “Mobility of Gold and Silver in Lateritic Weathering Profiles, Some Observations from Western Australia,” Economic Geology, Vol. 79, No. 1, 1984, pp. 38-49. http://dx.doi.org/10.2113/gsecongeo.79.1.38

[2]   J. G. Webster and A. W. Mann, “The Influence of Climate, Geomorphology and Primary Geology on the Supergene Migration of Gold and Silver,” Journal of Geochemical Exploration, Vol. 22, No. 1-3, 1984, pp. 21-42.

[3]   F. Colin and P. Vieillard, “Behavior of Gold in the Lateritic Equatorial Environment: Weathering and Surface Dispersion of Residual Gold Grains, at Dondo Mobi, Gabon,” Applied Geochemistry, Vol. 6, No. 3, 1991, pp. 279-290.

[4]   S. M. B. de Oliveira and E. G. Campos, “Gold-Bearing Iron Duricrust in Central Brazil,” Journal of Geochemical Exploration, Vol. 41, No. 3, 1991, pp. 233-244.

[5]   G. Bocquier, J. P. Müller and B. Boulange, “Les Laterites. Connaissances et Perspectives Actuelles sur les Mécanismes de Leur Differenciation,” In: Livre Jubilaire du Cinquantenaire, A.F.E.S., Paris, 1984, pp. 123-138.

[6]   C. Granier, P. Lajoinie and C. Vitali, “Géochimie de L’or et du Cuivre Dans les Formations Latéritiques Argileuses du Mont Flotouo (Ity, CBte d’Ivoire),” Bulletin de la Société Francaise de Mineralogie et de Cristallographie, Vol. 86, 1963, pp. 252-258.

[7]   J. S. Toom’s, “Exploration for Gold in the Humid Tropics,” International Geochemical Exploration Symposium, Toronto, 2-6 March 1962, p. 90.

[8]   R. Davy and M. El-Ansary, “Geochemical Patterns in the Laterite Profile at Boddington Gold Deposit, Western Australia,” Journal of Geochemical Exploration, Vol. 26, No. 2, 1986, pp. 119-144.

[9]   P. Lecomte and F. Colin, “Gold Dispersion in a Tropical Rainforest Weathering Profile at Dondo Mobi, Gabon,” Journal of Geochemical Exploration, Vol. 34, 1989, pp. 285-301. http://dx.doi.org/10.1016/0375-6742(89)90118-0

[10]   E. Ekomane, “Etudes Sédimentologiques et Paléoenvironnementales des Roches Carbonates et Pélitiques de la Formation de Mintom, Sud-Est Cameroun,” Ph.D. Thesis, l’Université de Yaoundé I, p. 189.

[11]   R. Letouzey, “Atlas du Cameroun, Phytogéographie Camerounaise,” Imprimerie Nationale, Yaoundé, 1968, p. 84.

[12]   B. Bessoles and R. Trompette, “Géologie de L’Afrique: La Chaine Panafricaine, Zone Mobile d’Afrique Central (Partie sud) et Zone Mobile Soudanaise,” Mémoire du BRGM, Orléans, Vol. 92, 1980, p. 378.

[13]   C. K. Shang, M. Satir, E. N. Nsifa, J. P. Liegeois, W. Siebel and H. Taubald, “Archean High-K Granitoids Produced by Remelting of the Earlier Tonalite-Trondhjemite-Granodiorite (TTG) in the Sangmelima Region of the Ntem Complex of the Congo Craton, Southern Cameroon,” International Journal of Earth Sciences, Vol. 96, No. 5, 2007, pp. 817-840.

[14]   C. Lerouge, A. Cocherie, S. F. Toteu, J. P. Milesi, J. Penaye, R. Tchameni, N. E. Nsifa and C. M. Fanning, “SHRIMP U-Pb Zircon Dating for the Nyong Series, South West Cameroon,” Journal of African Earth Sciences, Vol. 45, No. 4-5, 2006, pp. 413-427.

[15]   R. Tchameni, “Géochimie et Geochronology des Formations de l’Archéen et du Paléoprotérozoique du Sud-Cameroun (Groupe du Ntem, Craton du Congo),” Thèse de l’Université d’Orléans, 1997, p. 356.

[16]   M. Lasserre and D. J. Soba, “Age Liberien des Granodiorites et des Gneiss à Pyroxènes du Cameroun Meridional,” Bulletin du BRGM (Deuxième série), France, section IV, No. 1, 1976, pp. 17-32.

[17]   S. F. Toteu, W. R. Van Schmus, J. Penaye and J. B. Nyobe, “U-Pb and Sm-Nd Evidence for Eburnean and Pan-African High-Grade Metamorphism in Cratonic Rocks of Southern Cameroon,” Precambrian Research, Vol. 67, No. 3-4, 1994, pp. 321-347.

[18]   A. K. Charkravorty and D. K. Ghosh, “Kaolinite-Mullite Reaction Series: The Development and Significance of a Binary Aluminosilicate Phase,” Journal of the American Ceramic Society, Vol. 74, No. 6, 1991, pp. 1401-1406.

[19]   W. F. McDonough and S. Sun, “The Composition of Earth,” Chemical geology, Vol. 120, No. 3-4, 1995, pp. 223-253.

[20]   J. J. Braun, M. Pagel, J. P. Muller, P. Bilong A. Michard and B. Guillet, “Cerium Anomalies in Lateritic Profiles,” Geochimica et Cosmochimica Acta, Vol. 51, No. 3, 1990, pp. 597-605.

[21]   J. P. Ambrosi and D. “Nahon, Petrological and Geochemical Differentiation of Lateritic Iron Crust Profiles,” Chemical Geology, Vol. 57, No. 3-4, 1987, pp. 371-393.

[22]   P. D. Ndjigui, P. Bilong and D. Bitom, “Negative Cerium Anomalies in the Saprolite Zone of Serpentinite Lateritic Profiles in the Lomié Ultramafic Complex, South-East Cameroun,” Journal of African Earth Sciences, Vol. 53, No. 1-2, 2009, pp. 59-69.

[23]   G. H. Brimhall and W. E. Dietrich, “Constitutive Mass Balance Relations between Chemical Composition, Volume, Density, Porosity, and Strain in Metasomatic Hydrochemical Systems: Results on Weathering and Pedogenesis,” Geochimica Cosmochimica Acta, Vol. 51, No. 3, 1987, pp. 561-581.

[24]   P. Lecomte, “Stone Line Profiles: Importance in Geochemical Exploration,” Journal of Geochemical Exploration, Vol. 30, No. 1-3, 1988, pp. 35-61.

[25]   J. Gazel and G. Gerard, “Notice Explicative sur la Feuille Batouri Est (1/500 000),” D.M.G. Yaoundé, 1954, p. 43.