Elevation of top of Precambrian rocks from previous USGS studies of the Colorado Plateau

For use as part of a regional petroleum assessment, the USGS in the early 1990's developed a dataset reporting elevation on the surface of the Precambrian basement of the central and southern Colorado Plateau and vicinity (Butler, 1991). This dataset was released as paper report that included a table of basement elevations at more than 3,700 control points, including outcrop data of Precambrian rock on the plateau periphery, plus borehole data, seismic data, and depth estimated from a variety of published maps and stratigraphic sections. A contoured map of these data was released as a figure in an interpretive report (Blank and others, 1998). This digital dataset contains spatial datasets corresponding to the elevation of the Precambrian basement tabulated by Butler (1991) and the derived contour map (Blank and others, 1998). Basement elevation at control points is contained within a point feature class within the geodatabase. Points are attributed by type of data, method used to estimate top of Precambrian rocks from the data, and an estimation of the confidence in the reported elevation values. Contoured elevation data are contained in a line feature class within the geodatabase. Both types of data are also saved as individual shapefiles. Nonspatial tables define the data sources, terminology, and methods used.