The Plover Au deposit, located in Marathon County, WI, is host to a series of andesite, schist, and felsic/mafic intrusives which have undergone at least 3 phases of deformation, hydrothermal alteration, and greenschist grade metamorphism. With its proximity to the larger and better explored Reef Deposit, a more complete understanding of the formational history and geochemical footprint of the Plover prospect can add to regional understanding and better gold exploration models. For this study, two holes (PL-76-1 & PL-76-4), totaling ~1,180 linear feet of core were logged and described to highlight the volcanic stratigraphy and lithologic variety. Cores and samples were characterized by petrographic and geochemical analyses. Mineralization at the Plover deposit is characterized by cross-cutting vein networks containing boudins and vugs, and zones of brecciation. Hydrothermal alteration is suggested based on sericite/talc alteration within volcanic strata and zoned sulfide (pyrite, chalcopyrite, pyrrhotite), quartz, and calcite veins and vugs. Since high Au concentrations are typically present within brittle massive/semi-massive sulfide veins, formation of these deposits likely occurred after Penokean deformation/metamorphism and are related to a younger tectonic/magmatic event.
