DIGITAL CAPTURE AND ENHANCEMENT OF PALEOZOIC STRATIGRAPHIC AND GEOLOGIC CROSS SECTIONS IN THE CENTRAL APPALACHIAN BASIN

A series of regional stratigraphic cross sections through the Appalachian basin, published by the U.S. Geological Survey (USGS) between 1990 and 1997, are being converted to digital files for modeling-based, fossil-fuel resource investigations. These resulting digital files contain lithologic, stratigraphic, and structural data, which are essential for modeling programs that predict burial/thermal history, hydrocarbon generation, and fluid flow in the basin. Although the original cross sections incorporated only Cambrian and Ordovician strata, four of the sections will be expanded to geologic cross sections that include the entire Paleozoic sequence. Gamma ray logs, which are not shown on the original cross sections, have also been added. We use the following approach to create the digital files: 1) the cross section is digitally captured using autovectorization software; 2) gamma-ray well logs are scanned, traced with commercial software, and converted to Log ASCII Standard (LAS) files; 3) lithologic information is transcribed into a digital format using LITHOS, a spreadsheet-based computer program developed at the USGS. LITHOS permits the user to incorporate down-hole data from scanned images, text, and LAS files into one spreadsheet, which aids in standardizing the approach for picking formation tops and quantifying the components of stratigraphic units. We illustrate the process and benefits of our own digital compilation on a cross section that extends from Richland County, Ohio, to Rockingham County, Virginia.