Mine detail: Isle Royale Amygdaloid

Previously called 'Grand Portage Amygdaloid LodeIsle Royale LodeIsle Royale Amygdaloid Lode'

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Location

Lat / long: 47.11667, -88.56255

Resource(M)

Primary: Copper
Secondary: Silver
Ore: Copper, Silver
Gangue: Epidote, Pumpellyite-(Mg), Quartz, Sericite, Calcite, Datolite, Laumontite, Chalcocite, Domeykite
Orebody form: AMYGDALOIDAL LODE

Production

Operation type: Underground
Deposit type: Fissures, Secondary Enrichment
Production size: Medium
Development status: Past Producer
First production started: 1852
Last production ended: 1968

Geology

Host rock:Portage Lake Volcanics
Host type:Basalt
Structure:Isle Royale syncline and Grand Portage fault
Alteration processes:Early oxidation followed by epidotization/pumpellitization associated with mineralization

References

MRDSW060041
DEP10082608
Reference{Deposit:: BUTLER, B.S., AND BURBANK, W.S., 1929, THE COPPER DEPOSITS OF MICHIGAN: USGS PROF. PAPER NO. 144, 238 PP.}{Deposit:: WEEGE, R.J., AND POLLACK, J.P., 1971, RECENT DEVELOPMENTS IN THE NATIVE COPPER DISTRICT OF MICHIGAN: IN W.S. WHITE, (EDITOR), GUIDEBOOK FOR FIELD CONFERENCE, MICHIGAN COPPER DISTRICT; SEPT. 30-OCT. 2, 1971, SOC. ECON. GEOL., P. 19-43}{Deposit:: WHITE, W.S., 1968, THE NATIVE COPPER DEPOSITS OF NORTHERN MICHIGAN: IN J.D. RIDGE, (EDITOR) ORE DEPOSITS OF THE UNITED STATES 1933-1967, (GRATON-SALES VOL); AM. INSTIT. MIN. METALL. PETROL. ENG., V. 1, P. 303-325}{Deposit:: WHITE, W.S., 1956, GEOLOGIC MAP OF THE CHASSELL QUADRANGLE, MICHIGAN: USGS MAP MF-43, SCALE 1:24000.}{Deposit:: BODWELL, W.A., 1972, GEOLOGIC COMPILATION AND NONFERROUS METAL POTENTIAL, PRECAMBRIAN SECTION, NORTHERN MICHIGAN: HOUGHTON, MICHIGAN TECHNOLOGICAL UNIVERSITY, M.S. THESIS, 98 P.}{Deposit:: BORNHORST, THEODORE J., 1992, KEWEENAWAN COPPER DEPOSITS OF WESTERN UPPER MICHIGAN; AN OVERVIEW OF THE KEWEENAW PENINSULA NATIVE COPPER DISTRICT, MICHIGAN: GUIDEBOOK SERIES, VOL. 13, P. 33-62.}{Deposit:: WILBAND, J.T, 1978, THE COPPER RESOURCES OF NORTHERN MICHIGAN, USBM - J0366067.}{Deposit:: WILSON, M. L. AND DYL, S.J., II, 1992, MICHIGAN COPPER COUNTRY; MINERALOGICAL RECORD, V. 23, P. 29-41.}{Deposit:: JOHNSON, A.M. AND GROTH, E.H., 1998, INVENTORY OF UNDERGROUND MINES, HOUGHTON COUNTY, SITE ID 310029, MICHIGAN DEPARTMENT OF NATURAL RESOURCES.}{Production:: WEEGE AND POLLACK, 1971 WHITE, 1968}
ReporterNicholson, Suzanne, Sutphin, D.M., Mason Jr., G.T., Anderson, Arlene (M. Gere)