Sims, Paul K.

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Precambrian basement geologic map of Montana--An interpretation of aeromagnetic anomalies

Geologic map showing the structure and history of the basement rocks of Montana. Most of the state is covered by Phanerozoic bedrock units; the underlying basement structure must be inferred from magnetic anomaly data combined with geologic observations.

Precambrian basement structure map of the continental United States-an interpretation of geologic and aeromagnetic data

Principal basement structures formed during the Precambrian in the continental United States based on interpretation of regional aeromagnetic anomaly data of North America.