Mine detail: Grassy Island Prospect

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Location:	Koochiching County, Minnesota, United States, North America
Lat / long:	48.61806, -93.21467
dep_id:	10082805
mrds_id:	W062155
Commodity type:	metallic
Major mineral:	Gold
Operation type:	Unknown
Production size:	Unknown
Development status:	Unknown
ore:	Gold
gangue:	Chlorite, Pyrite, Quartz, Sericite, Specularite, Tourmaline
ore_ctrl:	Sims And Day (1992) Note That The Fundamental Regional Control On Gold Deposits In The Superior Province Is Transcurrent And Oblique Slip-Shear Deformation Zones That Formed In Late Archean Time.
Reporter:	Sutphin, David M. (Cannon, W. F.), Mason Jr., G.T.
Structure:	In The Quetico Subprovince Of The Superior Province. The Rainy Lake Area Lies Within A Dextral Wrench (Shear) Zone Bounded On The North By The Quetico Fault And On The South By The Rainy Lake-Seine River Fault.
tectonic:	Superior Province, Relatively Undisturbed Archean Craton, The Southern Half Of Which Consists Of Dominantly Alternating Belts Of Volcanic-Plutonic (Greenstone-Granite) Terranes And Metasedimentary Rock Terranes.
References:	Deposit:: GROUT, F.F., 1937, PETROGRAPHIC STUDY OF GOLD PROSPECTS OF MINNESOTA: ECONOMIC GEOLOGY, V. 32, NO. 1., P. 56-68. Deposit:: SIMS, P.K., AND DAY, W.C., 1992, A REGIONAL STRUCTURAL MODEL FOR GOLD MINERALIZATION IN THE SOUTHERN PART OF THE ARCHEAN SUPERIOR PROVINCE, UNITED STATES, IN SIMS, P.K., AND CARTER, L.M.H., EDS., CONTRIBUTIONS TO PRECAMBRIAN GEOLOGY OF THE LAKE SUPERIOR REGION: U.S. GEOLOGICAL SURVEY BULLETIN 1094-M, 19 P. Deposit:: DAY, W.C., 1990, BEDROCK GEOLOGIC MAP OF THE RAINY LAKE AREA, NORTHERN MINNESOTA: U.S. GEOLOGICAL SURVEY MISCELLANEOUS INVESTIGATIONS SERIES MAP I-1927, SCALE 1:50,000. Deposit:: DAY, W.C., AND SIMS, P.K., 1984, TECTONIC EVOLUTION OF THE RAINY LAKE AREA, NORTHERN MINNESOTA: GEOLOGICAL ASSOCIATION OF CANADA, THE MINERAL ASSOCIATION OF CANADA, LONDON, ONTARIO, CANADA, PROGRAM WITH ABSTRACTS, V. 9, P. 57.