DNR Report 201: 1981; Geological, Geophysical, and Geochemical Surveys of Lake, St. Louis and Cook Counties, Minnesota

Introduction extracted from page 1 of the report:

INTRODUCTION  This project was initiated as a result of funding from the 1980 Minnesota legislature to perform bedrock core drilling for mineral potential determination and to further the geologic knowledge of the State of Minnesota. The data in this report consists of geochemical, geophysical and geological surveys conducted by the Division of Minerals of the Minnesota Department of Natural Resources in Cook, Lake and St. Louis counties for the purpose of locating bedrock core drilling sites.


The areas surveyed were selected geochemical anomalies from regional lake sediment surveys previously conducted by the Division Of Minerals and from magnetic anomalies from aeromagnetic data derived by the Minnesota Geological Survey (Chandler and Walton, 1981). Agency policy parameters placed on the selection of core drilling sites included that there must be at least 50% state trust fund or tax-forfeited county mineral ownership; that sites should not be near already defined economic mineralization, and that drill sites must be located in or near the Duluth Complex but outside of the Boundary Waters Canoe Area. The areas where geochemical, geophysical, or geological surveys were conducted are shown on Figure 1.

The geological, geochemical and geophysical surveys conducted in Cook, Lake and St. Louis counties resulted in the selection of a number of drill sites in Lake County, of which two were drilled during January to March, 1981. Of two holes drilled in the Fools Lake area (Sec. 12, T59N, R11W), the first hole intersected an oxide gabbro with thin zones of up to 30% iron and titanium oxide, and the second hole contains traces of sulphide mineralization. A third hole drilled northeast of Toimi near Crest Lake (Sec. 10, T57N, R11W) intersected a banded troctolite with thin zones of oxide. The oxide zones in this drill hole frequently contain 5% total sulfides and up to 40% oxides assaying .22%-.25% copper and 9%-14% titanium oxide. Disseminated sulfides occur throughout the troctolite. These drilled anomalies represent portions of magnetic anomalies defined by aeromagnetic surveys conducted by the Minnesota Geological Survey. Few, if any, outcrops are known to occur over these anomalies, and the drill holes represent the first known sample of rock producing these anomalies. The results of these drill holes are significant, particularly the drill hole near Crest Lake, and suggest that further investigation may be productive.

This report consists of a presentation of the data, and no attempt to interpret the findings is made. Plates 1 through 12 contain the geophysical, geochemical and geological results obtained during this survey.


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Report 201: Geological, Geophysical, and Geochemical Surveys of Lake, St. Louis and Cook Counties, Minnesota; for the 1980 Drilling Project; various locations in T50N-63N R3E-14W
(18 pages, 8.5 x 11 inches, 1.28 MB)
Authors: M.K. Vadis, L.W. Gladen, and D.G. Meineke

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Map plates available

Plates 1-12: Reside on microfiche in the MN DNR Hibbing office.
Author: MN DNR, Lands and Minerals Division


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