Digital Geologic Map of Sherman Quadrangle, North-Central Texas

This data set was created for use in a regional ground-water model of the Lake Texoma watershed for a project by the U.S. Environmental Protection Agency, National Risk Management Research Laboratory located in Ada, Oklahoma, titled "Development of protocols and decision support tools for assessing watershed system assimilative capacity, in support of risked-based ecosystem management and restoration practices." Although this data set was created for use in a specific project, it may be used to make geologic maps, and determine approximate areas and locations of various geologic units. This digital data set contains geologic formations for the 1:250,000-scale Sherman quadrangle, Texas and Oklahoma. The original data are from the Bureau of Economic Geology publication, "Geologic Atlas of Texas, Sherman sheet", by J.H. McGowen, T.F. Hentz, D.E. Owen, M.K. Pieper, C.A. Shelby, and V.E. Barnes, 1967, revised 1991. Additional geology data sets are available for Oklahoma at URL "http://ok.water.usgs.gov/gis/geology/index.html". The source maps for three counties in the Oklahoma panhandle are at a scale of 1:125,000. The source maps for the rest of Oklahoma are at a scale of 1:250,000. The original geology source map was published in the Transverse Mercator Projection, Zone 14. This data set was projected to an Albers Equal Area projection (Synder, 1987), cast on the North American Datum of 1983. This electronic report was subjected to the same review standard that applies to all U.S. Geological Survey reports. Reviewers were asked to check the topological consistency, tolerances, attribute frequencies and statistics, projection, and geographic extent. Reviewers were given digital data sets and paper plots for checking against the source maps to verify the linework and attributes. The reviewers were asked to check the metadata and accompanying files for completeness and accuracy.