Principal basement structures formed during the Precambrian in the continental United States based on interpretation of regional aeromagnetic anomaly data of North America.
Digital and analog archives comprising more than 1,000 surveys, covering approximately 8,000,000 line-km of data, flown at various flight heights and line spacings
Probabilistic estimates of the amounts of undiscovered gold, silver, copper, lead, and zinc in conventional types of mineral deposits in the United States.
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.