For more information about this project refer to the following publication: Ruppel, S. C., Jones, R. H., Breton, C.L., and Kane, J.A., 2005, Preparation of maps depicting geothermal gradient and Precambrian structure in the Permian Basin: The University of Texas at Austin, Bureau of Economic Geology, Contract report to the U.S.Geological Survey, under order no. 04CRSA0834 and requisition no. 04CRPR01474.