Geology of the Huron River pitchblende occurrence, Baraga County, Michigan

Trace Elements Investigations 303
This report concerns work done on behalf of the Division of Raw Materials of the U.S. Atomic Energy Commission



Small quantities of uranium-bearing minerals were discovered by a geologist of the Jones and Laughlin Ore Company during the summer of 1949 along the East Branch of the Huron River, sec. 1, T. 51 N., R. 30 W., Baraga County, Mich. Subsequent diamond drilling of the prospect by the Jones and Laughlin Ore Company and the Ford Motor Company disclosed only minor amounts of radioactive materials at shallow depths in the immediate vicinity of the surface showings. Pitchblende and secondary uranium minerals occur as very small, discontinuous stringers and pods in calcite and quartz cementing the breccia within a low-angle shear zone that dips about 10 degrees to the southwest. The shear zone has a thickness of 10 to 30 feet and cuts black, locally carbonaceous slates of the upper Huronian Precambrian Michigamme slate. Mineral deposition during two hypogene stages and one supergene stage was identified in polished sections. The first phase consisted of the introduction of quartz and minor hematite into the sheared slate. After fracturing of the quartz the second stage was initiated by deposition of calcite, pyrite, rutile, pitchblende, bornite, sphalerite, chalcopyrite, galena, and greenockite. The supergene stage consisted of the development of metatyuyamunite, chalcopyrite, chalcocite, covellite, cuprite, volborthite, malachite, and goethite.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Geology of the Huron River pitchblende occurrence, Baraga County, Michigan
Series title Trace Elements Investigations
Series number 303
DOI 10.3133/tei303
Year Published 1955
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description Report: 21 p.; Plate: 26.39 inches x 30.24 inches
Country United States
State Michigan
County Baraga County
Other Geospatial Huron River
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
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