Résumé
The Barberton Greenstone Belt (BGB) contains over 350 gold occurrences and an estimated production of 342 tons, mainly from Fairview, New Consort, Sheba and Agnes mines. Many studies target these active mines to understand gold mineralisation. This study focuses on the distribution and structural control of hydrothermal veins, including in old mining areas and low-grade gold occurrences. The gold-bearing event is studied using spatial statistical analysis combined with structural field geology and mineralogical analysis. The hydrothermal/gold occurrences are distributed in several clusters. Two main tectonic events are involved in the formation of hydrothermal veins. A main deformation event related to large-scale folding and thrusting controls emplacement of gold-bearing veins during a single or pulsed NW-SE shortening in the northern BGB, and during an E-W shortening in the southern BGB. A late deformation event, produced by NE-SW shortening in the southern BGB is also related to late hydrothermal quartz veins. Quartz-carbonate veins are found in the northern mineralised system, whereas quartz-tourmaline-feldspars-carbonate +/- sulfides veins are present mainly in the southern BGB. The mineralised event in the BGB is structurally controlled by the main NW-SE to E-W shortening whereas additional quartz systems, not mineralised, seem to be controlled by an enigmatic NESW shortening.