Hercules Metals Corp V.BIG

Preservation

[Retiredgeo]

The Seven Devils volcanics are Triassic in age (~225 m.a.).  The porphyry was intruded ~200 m.a.. The Hercules rhyolite was dumped on top some time later (~160 m.a.).  The entire package was thrust faulted on top of the North American continent ~70 m.a.  This means that the entire rock package was faulted and broken up long after the mineralization and the Hercules rhyolite.  Preservation is greatest to the NW and worst to the SE.  The Hercules rhyolite is thickest to the NW and entirely eroded away to the SE.  Paleopreservation of the porphyry is believed to be greater to the NW (how much of it was preserved before the Hercules rhyolite buried it).