This map of the Archean and Proterozoic (Precambrian) geology of Minnesota is identical with MGS State Map S-21, except it portrays an interpretation beneath Phanerozoic (Paleozoic and Mesozoic) strata inferred from geophysical maps and drill core.
Bedrock map includes faults, form lines inferrred from geophysical data, dike locations and types, and geologic interpretations based on geophysics of the area of Minnesota that extends into Lake Superior.
Jirsa, M.A.; Boerboom, T.J.; Chandler, V.W..
S-22, Geologic Map of Minnesota, Precambrian Bedrock Geology.
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