Evolution des particules d'or en milieu lateritique soudano-sahelien; alluvions et colluvions dans l'environnement d'un gite filonien, Piela, Burkina Faso

Abstract

On a barren bedrock, transported auriferous materials of colluvial and alluvial origin present differences in the distribution, composition and morphology of gold particles. Under Sudano-Sahelian conditions, transport processes shape evolved particles in short distances.

Landform-regolith mapping in the West African context

“…Transported regolith can host secondary metal concentration such as alluvial placers, as exemplified by gold on active pediments in Burkina Faso (Ouangrawa et al, 2000;Bamba, 2010). Paleo placers should be considered in the detrital Fe duricrust of the paleo-glacis (3HgD, 4MgD).…”

“…16). Mechanical dispersion of these products on glacis / pediments should produce very wide halo stretched down slope, over hundreds of meters to several kilometers (Sanfo et al, 1993;Parisot et al, 1995;Ouangrawa et al, 1996Ouangrawa et al, , 2000Bamba, 2009Bamba, , 2010. Identification of such anomalies on the active pediment may be used to track its primary (endogenous) source upslope thanks to a topographic map at the appropriate resolution.…”

L’or, le zircon et la tourmaline : Traceurs de l’origine des materiaux des profils lateritiques d’afrique

“…Qu'il s'agisse du milieu équatorial ou du milieu subsahélien, l'or s'est révélé un traceur excellent au côté du zircon et de la tourmaline (Colin et al, 1997). Des études en milieu alluvial (Haubauer et Utter, 1977 ;Hérail, 1984 ;Hérail et al, 1990) ou en milieu latéritique (Freyssinet ,1993;Fressiney et al, 1987 ;Edou-Minko, 1988 ;Edou Minko et al, 1992;Sanfo et al, 1993: Sanfo, 1994Zang et Fyfe, 1993 ;Ouangrawa et al, 1996 ;Ouangrawa et al, 2000) ont montré l'existence de relations entre la forme des particules d'or et leur distance de transport à partir de la source primaire.…”

Experimental Abrasion Study of the Evolution of Gold Morphological Criteria in Different Sediments as a Function of Time

“…The dynamics of gold in surface materials in tropical regions have been the subject of numerous studies: [1] and [2], in the Gabonese forest; [3] [4] and [5] in the savannahs and steppes of Burkina Faso, [6] in eastern Senegal. In weathering profiles, gold particles often show evidence of having undergone dissolution.…”