A REGIONAL GEOPHYSICAL OVERVIEW OF THE GEOSWATH: PACIFIC NORTHWEST TO THE APPALACHIANS

The idea behind the GeoSwath is to undertake a highly integrated analysis of the structure and evolution of the lithosphere along a coherent path that extends from coast to coast. A major goal of this effort is to provide links between mapped geologic features, major structures in the upper crust, and deeper structures, and thus, to provide an improved understanding of the structure and evolution of North America. Databases of gravity and magnetic data have recently been complied for the U.S., and their analysis provides one way to attain a cost-effective initial analysis of the major crustal and upper mantle structures across the continent. We have created a series of gravity and magnetic maps of the areas that together cover the GeoSwath from the Pacific Northwest to the Appalachians. In addition, we have employed recent compilations of seismic reflection and refraction profiles to provide constraints on our integrated interpretations. When viewed together, these maps and data display many correlations with mapped geologic features that provide indications of the magnitude and lateral extent of these features. They also reveal relationships between known geologic features and contain anomalies whose geologic interpretation is not clear. In the latter case, these maps suggest areas and features worthy of further attention by EarthScope and related projects.