Page 370 - NEWGEN21-Proceedings-Full

DEPOSIT GEOLOGY

Orebody Characteristics

▪ Host Rocks: ANTENNA
▪ Known deposits can be grouped into three distinct litho-structural
corridors (from west to east) – the Antenna, Koula-Ancien and Boulder-
Gabbro corridors.
▪ All lithologies can be mineralised, but more reactive lithologies (e.g.
high-Fe basalts and the Antenna rhyolite) more susceptible to alteration
and infiltration by mineralising fluids.

▪ Structure:
▪ D1 shearing and extensive mylonitisation => ground preparation.
▪ D2 brittle/ductile dilationary structures and reactivation of D1 shears
and mylonites.
▪ Alteration and Metamorphism:
▪ Protracted infiltration of mineralising silica-CO -K-S-Ca-Fe-(Au)
2
hydrothermal fluids at lower to middle greenschist P-T conditions has to
some degree modified all rock types (excluding late intrusives) at each
of the Séguéla deposits.
▪ Variation of a silica-albite-muscovite/sericite-biotite-Fe carbonate-
chlorite proximal alteration assemblage.
▪ Alteration intensity decreases rapidly outwards from the core of
deposits to distal sericite-chlorite-calcite-epidote alteration, generally
only over a few metres. ANCIEN