Michigan · Houghton County
Past Producer

Isle Royale Amygdaloid

Houghton County, Michigan, United States
CopperSilver
⌖ Show on mapUSGS source ↗
Commodities
PrimaryCopper
SecondarySilver
Commodity typeM
Deposit
Deposit typeFissures, Secondary Enrichment
Model96: Native Cu
Deposit sizeM
Orebody formAMYGDALOIDAL LODE
Materials
Ore mineralsCopper, Silver
GangueEpidote, Pumpellyite-(Mg), Quartz, Sericite, Calcite, Datolite, Laumontite, Chalcocite, Domeykite
Geology
Host rockBasalt · Portage Lake Volcanics
StructureIsle Royale syncline and Grand Portage fault
AlterationEarly oxidation followed by epidotization/pumpellitization associated with mineralization
Economic & production
Development statusPast Producer
First production1852
Last production1968
Identification
Deposit ID10082608
MRDS IDW060041
Alternate namesGrand Portage Amygdaloid Lode, Isle Royale Lode, Isle Royale Amygdaloid Lode
RegionNA
Data scoreB
Coordinates47.09778, -88.58033
References
BUTLER, B.S., AND BURBANK, W.S., 1929, THE COPPER DEPOSITS OF MICHIGAN: USGS PROF. PAPER NO. 144, 238 PP.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. 19-43WHITE, 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. 303-325WHITE, W.S., 1956, GEOLOGIC MAP OF THE CHASSELL QUADRANGLE, MICHIGAN: USGS MAP MF-43, SCALE 1:24000.BODWELL, W.A., 1972, GEOLOGIC COMPILATION AND NONFERROUS METAL POTENTIAL, PRECAMBRIAN SECTION, NORTHERN MICHIGAN: HOUGHTON, MICHIGAN TECHNOLOGICAL UNIVERSITY, M.S. THESIS, 98 P.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.WILBAND, J.T, 1978, THE COPPER RESOURCES OF NORTHERN MICHIGAN, USBM - J0366067.WILSON, M. L. AND DYL, S.J., II, 1992, MICHIGAN COPPER COUNTRY; MINERALOGICAL RECORD, V. 23, P. 29-41.JOHNSON, A.M. AND GROTH, E.H., 1998, INVENTORY OF UNDERGROUND MINES, HOUGHTON COUNTY, SITE ID 310029, MICHIGAN DEPARTMENT OF NATURAL RESOURCES.WEEGE AND POLLACK, 1971 WHITE, 1968