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A magnetic anomaly near Bear Lake, Houghton County, Michigan

January 1, 1952

A large magnetic anomaly of unknown origin occurs about 1 1/2 miles east of Bear Lake, Houghton County, Michigan, in secs. 24 and 258 T. 56 N., R. 34 W. The occurrence is isolated in an area of very weakly magnetic rocks and has special geologic interest because it is adjacent to a non-magnetic rhyolite porphyry body that is stratigraphically higher than any other known igneous rock in the Keweenawan series.

An aeromagnetic survey of the Michigan copper district by the Geophysics Branch of the U. S. Geological Survey in 1948 first revealed the anomaly (Fig. 1). The anomalous area has been more fully outlined by a dip-needle survey, and briefly discusses the geology of the area and possible significance of the anomaly.

Publication Year 1952
Title A magnetic anomaly near Bear Lake, Houghton County, Michigan
DOI 10.3133/ofr52169
Authors James C. Wright
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 52-169
Index ID ofr52169
Record Source USGS Publications Warehouse