Graphite Creek adit

USGS Geologist Susan Karl investigates an outcrop of massive flake graphite (dark gray rock) at the Graphite Creek deposit located on the Seward Peninsula, Alaska. An adit, a horizontal passage leading into a mine for the purposes of access or drainage, from historical mining is visible in the corner. The Graphite Creek deposit is the largest flake graphite resource in the US. The investigation concluded that high-temperature metamorphism and partial-melting of the host rocks enriched graphite to economic grades.