Mass Mine, Mass Consolidated Mine, Mass City, Ontonagon Co., Michigan, USA
|Latitude & Longitude (WGS84):||46° 45' 50'' North , 89° 5' 10'' West|
|Latitude & Longitude (decimal):||46.76389,-89.08611|
|Other regions containing this locality:||Keweenaw Peninsula, Michigan, USA|
An underground copper mine consisting of three shafts adjacent to Mass City, MI. The Mass Mining Co. was organized in 1856 and worked sporadically until 1888, when the mine operations ceased for good. The mine was merged into the Mass Consolidated Mining Co. in 1899. A wide range of minerals can be found at the original Mass Mine site, including copper, silver, and datolite.
14 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 - 1200 Ma
|Portage Lake Volcanics|
Age: Stenian (1000 - 1200 Ma)
Stratigraphic Name: Portage Lake Volcanics
Comments: This unit is the same as unit Yp on paper map of Sims (1992). Description is taken from that unit description.
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. 
Butler, B.S., and Burbank, W.S., 1929, The Copper Deposits of Michigan. U.S. Geological Survey. Professional Paper 144. 238 pp.
The Copper Country Rock & Mineral Club, 2001, Red Gold and Tarnished Silver, 2nd Ed., 44 pp.