GRAVITY AND MAGNETIC ANALYSIS OF THE MIDCONTINENT RIFT SYSTEM IN IOWA
A large segment of the MCRS transverses Iowa, which to date has only been generally investigated geophysically with little information regarding the lower crustal and upper mantle structure under the rift. In order to understand the crustal and upper mantle structure, we will analyze the available gravity and magnetic data in Iowa. Residual gravity and magnetic anomaly maps clearly outline the main rift system with maxima anomalies over the basalt and minima anomalies over the flanking rift basins. To further the investigation, four profiles, perpendicular to the rift were constructed using gravity and magnetic data. These 2D models will be constrained by previous gravity and magnetic models performed elsewhere on the MCRS, seismic reflection data, basement penetrating drillholes and broadband seismic results from the recent Earthscope experiment. The models will be integrated with 2D inverse models for the Earthscope long period magnetotelluric experiment in order to determine the crustal and upper mantle structure of the Iowa segment of the MCRS. These models will aid us in determining if mantle anomalies still persist from the extrusion of large amounts of mafic material from the upper mantle.