DIGITAL CAPTURE AND ENHANCEMENT OF CAMBRIAN AND ORDOVICIAN STRATIGRAPHIC CROSS SECTIONS IN THE CENTRAL APPALACHIAN BASIN

A series of six U.S. Geological Survey geologic cross sections (published by Ryder and others between 1990 and 1997) have been digitally captured and enhanced for the Appalachian Basin Framework project of the U.S. Geological Survey (USGS). The cross sections depict the structure of block-faulted Proterozoic basement rocks and early Paleozoic strata across the Appalachian Basin from Pennsylvania to Tennessee. The early Paleozoic strata are grouped into the following three stratigraphic packages: (1) Middle-Cambrian siliciclastic and carbonate strata (rift deposits of the Rome trough); (2) Cambrian-Ordovician passive carbonate strata (passive margin carbonate bank); and (3) Upper Ordovician-Lower Silurian siliciclastic strata (deposits of the Taconic orogeny). In addition to the line-work on the original cross sections, gamma-ray log traces of stratigraphic control points were added to each drill hole on the digital reconstructions. The digitally captured files permit a more readily accessible product with the added functionality of optional client-based editing (e.g., altering stratigraphic contacts, control points, and/or structural attributes). The USGS is currently using these digitally enhanced cross sections to provide geological constraints for modeling regional fluid-flow migration paths. Two of the six cross-sections are available on-line at http://pubs.usgs.gov/products/maps/i-maps.html in .AI, .EPS, and .PDF file formats.