Antimony deposits in the Variscan Armorican belt, a link with mafic intrusives?

International audienceThe Variscan Armorican belt was the World leading producerof antimony at the beginning of the twentieth century. However,geological controls on the deposits remain unconstrained.Here, we illustrate the field setting ofmineralisations and perform a statistical analysis using GeographicalInformation System software, geophysical and geologicaldata. The analysis shows that Sb deposits are spatiallycorrelated with high-density and magnetic zones. This mayreflect the presence of mafic/ultramafic bodies at depth – asuggestion that is further supported by numerous occurrencesof doleritic dykes throughout the region. Future antimonyprospecting should focus on the high-density and high-magneticzones which comprise about 18% of the Armorican massif.Links between Sb deposits and mafic intrusions arerecognised elsewhere in the West European Variscan belt,emphasising that these may be key for antimony prospectingin deformation belts