Carnes Quarry (Johnson Materials Co.)

 Copper mine near Carnes Quarry site

Copper mine near the site of the present day Carnes Quarry, Douglas County, Wisconsin, circa 1900. Photo courtesy of the Wisconsin State Historical Society.

LOCATION: East of South Range, SW SW SW sec. 31 T48N R.12W, Douglas County, Wisconsin

ACCESSIBILITY: Posted private property, periodically active quarry

GEOLOGY:Tilted and faulted amygdaloidal Keweenawan basaltic lava flows. Flow top structures visible. Minerals mostly fill amygdules, or are found in veins and along faults.

MINERALOGY NOTES:

Augite - in groundmass, also as phenocrysts. Largely replaced by epidote and chlorite.
Calcite - white cleavable massive.
Chlorite - massive, fine-grained scaly and spheres on quartz xls.
Chalcopyrite - massive, brassy to slightly iridescent.
Epidote - abundant as crystals in amygdules, also massive replacement of primary minerals in the basalt groundmass.
K Feldspar - pink massive adularia in amygdules. Also euhedral xls. showing pseudo-rhombohedral habit, with quartz
Plagioclase -as phenocrysts and in basalt groundmass. Largely replaced by epidote and other minerals.
Prehnite - green botryoidal, crude xls in amygdules.
Quartz - several habits: clear to white massive, locally euhedral xls. several cm. long, also sky blue massive, smoky massive and as pale white, tan or pink banded agate.
Unknown - Insoluble greenish fibers with epidote, etched from massive calcite. Actinolite? Pumpellyite?
COMMENTS: colorful combination of quartz, (massive and agate), K feldspar, epidote, chlorite and calcite in amygdules in black basalt.

BIBLIOGRAPHIC REFERENCES: Cordua, 1995 field notes.

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