REDUCTION TO THE POLE OF THE NORTH-AMERICAN MAGNETIC-ANOMALIES

Magnetic anomalies of North America are reduced to the pole using a generalized technique which takes into account the variations in the directions of the core field and the magnetization of the crust over North America. The reduced-to-the-pole magnetic anomalies show good correlations with a number of regional tectonic features, such as the Mid-Continental rift and the collision zones along plate boundaries, which are also apparent in the vertical gravity gradient map of North America. The magnetic anomalies do not, however, show consistent correlation with the vertical gravity gradients, suggesting that magnetic and gravity anomalies do not necessarily arise from common sources. -Authors