MINNESOTA BIRCHDALE-INDUS Area - SULFIDE MINERALIZATION, Koochiching County 1977

Description

SCARCE HISTORIC ITEM!!
This is Minnesota Geological Survey Report of Investigations 17:
Geology, Sulfide Mineralization and Geochemistry of the Birchdale-indus Area, Koochiching County, Northwestern Minnesota
. This scarce old report published in 1977 comes complete with the original geologic map in a pocket in the back and a fold out map in the text.
This is a nice study of some interesting Archaean rocks in northern Minnesota. The area is between the Red Lakes and Lake of the Woods and stretches a couple hundred miles east and west. The rocks are part of the Wabigoon Volcanic Belt of Canada, and include various volcanic rock
s, intrusive rocks, felsic dikes, tuffs, iron formation and later granites. The structure is complex with significant folding and faulting.
This area has been explored for metal deposits without notable success even though the rock types seem like they would be prospective. One hindrance is that the rocks are not well exposed. Swamps and glacial till cover areas making the geology a bit difficult to put together. This study took all the available information and pulled it together into one report, with a new map to go with it, It details the geology, rock types and mineralization. In addition to base metals exploration, some gold has been produced form a few areas. Other areas have been tested with small pits and shafts. It seems like a fertile area that just lacks good exposures. Perhaps there is still something to be found here. This report could help, or just make for interesting reading about a little-known area.
These state publications are often harder to find than USGS bulletins. Don't miss it.
Expert packing assured. The recent increase in postage rates was pre
tty big. As a result, Media Mail is now my default shipping method to keep shipping affordable.
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