Intense faulting and fracturing in the Harris Lake area) northeastern Minnesota are documented by detailed field studies. Faults are identified chiefly by the disruption of mappable layers within sequences of plagioclase and plagioclase-olivine cumulates. Most layers grade from olivine-rich bottoms to plagioclase-rich tops and were probably deposited by density currents. Faults trend principally N35?E, N05?W, and N40?W. The recognition of intense faulting and fracturing in this region and an understanding of the currents responsible for cumulate deposition establish a basic geologic framework with important local and regional implications.
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USGS Numbered Series
Preliminary geologic report on the Harris Lake area, northeastern Minnesota