Art Bookstrom, PhD (Former Employee)

USGS scientist Steve Box takes an oriented sample of folded, crenulated, and metamorphosed banded siltite, exposed in the Blacktail pit of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho.

USGS scientist Tom Frost measures the distance across the transition from garnet-bearing rocks, upslope from the end of the tape, to garnet-free rocks below it, as exposed on the northeast wall of the Blacktail pit of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho.

USGS scientist Tom Frost stands on the northeast rim of the Blacktail pit of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho.

USGS scientist Art Bookstrom photographs copper-stained banded siltite, exposed in the Blacktail pit of the Blackbird cobalt-copper mine, Salmon River Mountains, east-central Idaho.

USGS scientist Art Bookstrom uses a hand-lens to search for sulfide minerals in oxidized copper-cobalt-bearing siltite of the banded siltite unit of the Apple Creek Formation, exposed in the Blacktail pit of the Blackbird cobalt-copper mine, Salmon River Mountains, east-central Idaho.

USGS scientist John Slack holds his hammer to a biotitic mafic dike, intruded into twice-folded banded siltite, exposed in the Hawkeye adit of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho. Biotite is a type of mica, and mafic refers to a high magnesium and iron content.

USGS scientist Art Bookstrom looks at puzzling sedimentary structures in metasedimentary rocks of the Apple Creek Formation, near the Jackass prospect, near Iron Creek, in the southeastern part of the Idaho cobalt belt, in east-central Idaho.

USGS scientist Art Bookstrom looks at greenish copper stain and pale pink cobalt bloom on limonite-stained meta-siltite and meta-argillite at the No Name prospect, near Iron Creek, in the southeastern part of the Idaho cobalt belt, in east-central Idaho.

USGS scientist Art Bookstrom hammers on limonite-stained breccia, cutting banded siltite of the Apple Creek Formation, exposed near the Uncle Sam portal of the Blackbird cobalt-copper mine, in the Salmon River Mountains of east-central Idaho.

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.

Cross-bedded sandstone of the Gunsight Formation of the Mesoproterozoic Lemhi Group. These beds are interpreted as products of alluvial sedimentation in a deltaic setting.

A thick lens of biotite-rich rock, interlayered with thick beds of cross-bedded meta-sandstone + scapolite of the Gunsight Formation of the Lemhi Group in the Lemhi sub-basin of the Mesoproterozoic Belt Basin. The biotite-rich rock is exposed in a prospect pit above the Sweet Repose mine adit.

Quartz vein in biotite-rich rock in the Gunsight Formation of the Mesoproterozoic Lemhi Group. Bluish green copper-bearing minerals coat the quartz vein. Pale pinkish cobalt bloom and white caliche coat adjacent biotite-rich wallrock.

Outcrop of biotitic meta-sandstone in the lower part of the Gunsight Formation, cut by white quartz veins with alteration envelopes of coarsely crystalline black biotite and minor muscovite. USGS intern, Shane Kostka prepares to collect representative samples from this outcrop.

Small-scale syncline in siltite of banded siltite unit of Apple Creek Formation, within a zone of tight, north-plunging chevron folds, exposed on the south-facing slope above the upper part of Little Deer Creek, east of the Blackbird cobalt-copper mine area, in east-central Idaho.

Outcrop of the banded siltite unit of the Apple Creek Formation of the Lemhi Group, in the Lemhi sub-basin of the Mesoproterozoic Belt Basin. This exposure is along the Deep Creek road, southeast of the Blackbird cobalt-copper mine area, in the Salmon River Mountains of east-central Idaho.

Outcrop of the banded siltite unit of the Apple Creek Formation, east of the Slippery Gulch fault, and south of the Blackbird cobalt-copper mine area, in the Salmon River Mountains of east-central Idaho.

Limonite-stained outcrop of the banded siltite unit of the Apple Creek Formation, near Blackbird Creek, south of the Blackbird cobalt-copper mine area, in the Salmon River Mountains of east-central Idaho.

Mylonitic breccia in alluvium of Little Deer Creek, downstream from a moderately west-dipping contact between biotitic quartzite of the Gunsight Formation, which is structurally overlain by garnet-chloritoid-bearing banded siltite of the banded siltite unit of the Apple Creek Formation.

Blocks of biotitic meta-sandstone from the lower part of the Gunsight Formation, and drill core from the underlying banded siltite unit of the Apple Creek Formation, lying on the dump of the lower workings of the Copper Queen mine, southeast of the Blackbird cobalt-copper mine area.