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A Gossan at the Blackbird Cobalt-Copper Mine

Detailed Description

USGS scientist Art Bookstrom maps and samples a gossan, developed on tightly folded, mineralized, metamorphosed, and weathered banded siltite, exposed on the southwest rim of the Blacktail pit of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho. The gossan is overlain by unconsolidated colluvial debris. A gossan is an intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.


Public Domain.