|Latitude & Longitude (WGS84):||46° 47' 3'' North , 89° 35' 10'' West|
|Latitude & Longitude (decimal):||46.78417,-89.58611|
|Other regions containing this locality:||Keweenaw Peninsula, Michigan, USA|
|Köppen climate type:||Dfb : Warm-summer humid continental climate|
Commodities (Major) - Silver
Development Status: Prospect
Host Rock Unit: Portage Lake Volcanics
Host Rock: Basalt
The Boston and North American Mining Company sank one shaft on this site in 1845 in hopes of finding copper. What was found was very little copper and some silver in the shaft, but not enough to continue exploration and the site was abandoned in 1846.
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
1000 - 1600 Ma
|Copper Harbor Conglomerate|
Age: Mesoproterozoic (1000 - 1600 Ma)
Stratigraphic Name: Copper Harbor Conglomerate
Comments: Note: The unnamed formation has since been named the Porcupine Volcanics (Ypv).
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
1000 - 1200 Ma
|Mesoproterozoic sedimentary rocks|
Age: Stenian (1000 - 1200 Ma)
Comments: Mid-Continent Rift
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.