Crustal Architecture Beneath the Southern Midcontinent (USA) -- Data Grids and 3D Geophysical Models: Elevation surface grids

Regional surface elevation grid files provided in Grid eXchange File (GXF) format were used to study crustal architecture beneath the Southern Midcontinent (USA) by McCafferty and others (2019). The study covered a rectangular, multi-state area of 924 by 924 kilometers centered on Missouri, and a corresponding volume extending from the topographic surface to a depth of 50 kilometers below sea level. The grid files (magnetic field observation surface, topographic surface, Precambrian basement surface, and Moho interface) were used to construct templates and initial physical property models for 3D inversions. A masked version of the Precambrian basement surface grid was used to remove inverted densities and magnetic susceptibilities in areas where the basement elevation is unknown All grids are sampled at a 2,000 by 2,000 meter grid interval. Missing data nodes are assigned a value of 1.000000E+38. Two versions of each GXF file are provided: (1) a version with embeded map projection information for use with Geosoft Oasis montaj and the free Geosoft viewer software and (2) a version without map projection information (filenames ending in NoProj.gxf) for use with ArcMap and QGIS. An ArcMap projection file, which contains the missing projection information, is also provided.