Evidence for Syngenetic Precious Metal Enrichment in an Appalachian Volcanogenic Massive Sulfide System: The 1806 Zone, Ming Mine, Newfoundland, Canada

The Ming deposit, Baie Verte, Newfoundland, Canada, is an Early Ordovician bimodal-mafic, Cu-Au-(Zn-Ag) volcanogenic massive sulfide (VMS) deposit. The deposit consists of a number of ore lenses that are stacked in the uppermost part of the Rambler rhyolite. One of the uppermost lenses, the 1806 zone, is enriched in Au and Ag. The deposit has been affected by Silurian-Devonian greenschist to amphibolite grade metamorphism and polyphase deformation and this has led to debates as to whether the Au-Ag enrichment in the deposit is syngenetic or a product of a later metamorphic and structural overprint. The 1806 zone consists predominantly of discordant sulfide stringer, stratabound semimassive to massive sulfides and a weakly mineralized silicified cap zone. The ore is largely hosted within the footwall Rambler rhyolite that is strongly altered to quartz-sericite ± green mica with sporadic chlorite-biotite. Base and precious metal zoning is developed from the down-plunge portion (Cu-Au)