Mansfield Mine, Crystal Falls, Menominee iron range, Iron Co., Michigan, USA
|Latitude & Longitude (WGS84):||46° 6' 59'' North , 88° 13' 12'' West|
|Latitude & Longitude (decimal):||46.11639,-88.22000|
Commodities (Major) - Iron
Deposit Type: Secondary Enrichment
Development Status: Past Producer
Deposit Model: 241: Superior Fe (BC name is Lake Superior & Rapitan types iron-formation)
Host Rock: Iron Formation
An iron mine worked from 1890 to 1913. This mine worked the Proterozoic Hemlock Volcanics Iron-formation of the Marquette Range supergroup. The roof of one part of this mine passed very close to the bed of the Michigamme River, close enough that miners could hear logs grinding against the river bottom as the logs floated down the river to sawmills. On September 28, 1893, the roof gave way under the river, flooding the mine and taking 27 lives.
7 valid minerals.
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
1600 - 2500 Ma
|Menominee Group; Hemlock Formation|
Age: Proterozoic (1600 - 2500 Ma)
Stratigraphic Name: Hemlock Formation
Comments: Continental margin assemblage (north of Niagara Fault)
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. 
Cannon, W. F. (1999) "Digital Geologic Map of the Penokean Continental Margin, Northern Michigan and Wisconsin", U.S. Geological Survey Open-File Report 99-547, U. S. G. S., Reston, VA.
BAYLEY, R. W., 1959, GEOLOGY OF THE LAKE MARY QUADRANGLE,IRON COUNTY, MICHIGAN. WASHINGTON, U.S. GOVT. PRINTING OFFICE, 1959 PP. 40-44.
LAKE SUPERIOR IRON ORE ASSOCIATION, 1938, LAKE SUPERIOR IRON ORES (1ST ED.): CLEVELAND, OHIO.
LAKE SUPERIOR IRON ORES, MINING DIRECTORY AND STATISTICAL REPORT, PUBLISHED BY THE LAKE SUPERIOR IRON ORE ASSOCIATION, 1952.