Thickness, character, and structure of upper Permian evaporites in part of Eddy County, New Mexico

Between Project Gnome site and the International Minerals and Chemical Corporation's plant site, in central eastern Eddy County, N. Mex., unconsolidated deposits of Quaternary age and redbeds of Triassic age attain a thickness of about 700 feet, and rest unconformably on evaporites of late Permian age. The upper Permian evaporites are 3,000 to 3,800 feet thick, and they are divided, in descending order, into the Rustler, Salado, and Castile formations. The Rustler is largely gypsum rock, the Salado is dominantly halite rock, and the Castile contains both anhydrite rock and halite rock. The salt and anhydrite beds of the Salado and Castile are intruded by narrow dikes of alkalic rock along which the evaporites are little altered. The sedimentary rocks have a generally southeastward regional dip, but locally are warped in gentle folds of low amplitude and fairly small lateral dimensions.