Long-wavelength aeromagnetic anomaly map of the conterminous United States

Abstract

Total intensity magnetic anomaly unflltered and low-pass filtered profile and contour maps of the conterminous United States have been prepared from data provided by the U.S. Naval Oceanographic Office9s Project MAGNET Survey. The maps are useful for regional geological investigations because the anomalies, particularly on the filtered maps that emphasize long-wavelength anomalies, can be correlated with known major geologic features. The most intense positive, long-wavelength anomaly occurs over Precambrian mafic basement rocks in eastern Tennessee and Kentucky. Other examples of prominent positive anomalies occur over the Great Valley of California and the Colorado Plateau and along the Appalachian fold belt. In contrast, prominent negative long-wavelength magnetic anomalies occur over the Cascade Mountains, Mississippi Embayment, and southern Rocky Mountains and marginally to the positive anomaly related to the Mid-continent Rift.