Antimony deposits in the Variscan Armorican belt, a link with mafic intrusives?
Résumé
The Variscan Armorican belt was the World leading producer
of antimony at the beginning of the twentieth century. However,
geological controls on the deposits remain unconstrained.
Here, we illustrate the field setting of
mineralisations and perform a statistical analysis using Geographical
Information System software, geophysical and geological
data. The analysis shows that Sb deposits are spatially
correlated with high-density and magnetic zones. This may
reflect the presence of mafic/ultramafic bodies at depth – a
suggestion that is further supported by numerous occurrences
of doleritic dykes throughout the region. Future antimony
prospecting should focus on the high-density and high-magnetic
zones which comprise about 18% of the Armorican massif.
Links between Sb deposits and mafic intrusions are
recognised elsewhere in the West European Variscan belt,
emphasising that these may be key for antimony prospecting
in deformation belts.