Star Mine, Copper Harbor, Keweenaw Co., Michigan, USA
|Latitude & Longitude (WGS84):||47° 28' North , 87° 53' West|
|Latitude & Longitude (decimal):||47.46667,-87.88333|
|Other regions containing this locality:||Keweenaw Peninsula, Michigan, USA|
|Köppen climate type:||Dfb : Warm-summer humid continental climate|
An underground copper mine consisting of four shafts and two adits located southeast of Copper Harbor, or one mile south of the Clark Mine. The Star Copper Company was organized in 1851 nad began producing copper in 1855. Work was suspended in 1859, but resumed in 1864 due to rising copper prices. Prices dropped again in 1865, forcing the mine to close once again. The mine reopened briefly in 1872 and again in 1881 but closed permanently in 1882. The company remained organized in hopes of reopening the mine, but never did. The property was sold around 1908 to Calumet & Hecla Mining Co.
As with Clark Mine, datolite is the main attraction here, and some very nice specimens can still be found on the rock piles. Prehnite and copper can also be found here. Beware however, that the piles are covered with 120+ years of overgrowth, so finding them can be tricky.
4 valid minerals.
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.