THE USE OF RESISTIVITY AND INDUCED RECONNAISSANCE FOR GOLD BEARING (NORTH-EAST MASSIF CENTRAL, FRANCE)

At Varennes (Creuse) , sulfides (pyrite and arsenopyrite with gold) were found in the vicinity of faults (shear zones) which divide a volcano-sedimentary basin into metric to decametric compartments formed mainly by rhyolitic tuffs and breccias. Resistivity measurements carried out using the gradient array mode with two different spacings and directions contributed to the definition of the local structural scheme, based on two normal faulting systems. Induced polarization readings taken using the same array showed stronger anomalies at the fault junctions and along discrete subvertical faults striking N15 00, which channelled hydrothermal fluids, the source of the ore mineralization.