Alaska Geophysical Survey Interpretation

Science Center Objects

Available geophysical data for Alaska have not been fully exploited. Project objectives were to conduct systematic analysis of existing gravity, aeromagnetic and airborne electromagnetic data to map geologic trends, structural geologic and tectonic patterns, and identify key lithologies for direct integration with geologic framework and mineral potential studies.

Science Issue and Relevance

Alaska is a geologic frontier with substantial mineral resource potential. Complex geology, limited outcrop, and high logistical costs make airborne geophysics essential for efficient reconnaissance. Available geophysical data for Alaska have not been fully exploited. Project objectives were to conduct systematic analysis of existing gravity, aeromagnetic and airborne electromagnetic data to map geologic trends, structural geologic and tectonic patterns, and identify key lithologies for direct integration with geologic framework and mineral potential studies.

AK aeromagnetic anomaly map

Revised merged magnetic anomaly map of Alaska. Figure 4 from Connard and others, 1999, USGS Open-File Report 99-503.

(Public domain.)

Method to Address Issue

Project activities focused on performing an advanced analysis of the Alaska Division of Geological & Geophysical Surveys (DGGS) surveys based on USGS processing methods.

Airborne Data Processing and Geophysical Feature Mapping: The primary objective was the production of geophysical feature maps from reprocessed high-resolution airborne geophysical data that highlight physical property variations and structural features in the shallow subsurface. The workflow involved systematic data quality assessment, processing, integration, and production of geologically relevant quantitative maps and cross-sections including electromagnetic inversion and complimentary magnetic interpretation. 

New Regional Aeromagnetic Map of Alaska: The last published magnetic data compilation for Alaska was released by the USGS in 1997. New data and advances in data compilation methods allowed for significant improvement of the previous compilation. The objective was to release an updated regional magnetic data compilation for Alaska. The new Alaska magnetic data compilation used all available data, incorporated satellite magnetic data for leveling, and utilized the latest compilation methods to improve the 1997 compilation.

Geophysical Basement Maps of Alaska: The goal was to significantly improve the current Tertiary basin framework that dates from the Decade of North American Geology (DNAG) effort (Kirchner, 1994).

Reference Cited:  Kirchner, C., 1994, Map showing sedimentary basins in Alaska (DNAG Alaska Volume G-1): Geological Society of America, 1 plate (scale 1:2,500,000).

 

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