Graphite: Roadcut occurrence near

Gooderham, Ontario, Canada

Petrology

Geological map of the area south of Gooderham, Ontario showing intrusive rocks amongst graphite-bearing carbonate. metasediments. The spherical-graphite-bearing calcite boudins are exposed along the east side of Highway 507. Modified from Ontario Department of Mines Map 2173 Glamorgan Township.

Roadcut on the east side of Highway 507, south of Gooderham, Ontario. Note the highly sheared layers and the calcite boudin to the right of the scientist.

10 by 8 inch cross section of a calcite lens, containing several 1-mm graphite spheres. Adjacent rock is graphitic marble mylonite and feldspar/amphibole skarn. Note brecciation of the scarn from shearing. John A. Jaszczak collection and photo.

Calcite bearing spherical graphite with adjoining gneissic, schistose, and marble layers. This is the same boudin shown to the right of the scientist in the roadcut above.

Schematic of a calcite lens showing the spatial relationship among the various rock types and graphite aggregates. Also shown are delta 13C (per mil) values.