Geologic history of Painthorse Quadrangle, Culberson County, Texas

The Painthorse quadrangle was an area of deposition during every geologic period except the Triassic, Jurassic and Tertiary. Prior to Permian time the area was situated on an unstable shelf which, from time to time, was covered by shallow epicontinental seas. The orogeny at the end of Pennsylvanian time marked the area's transition from a shelf-type depositional region to an intracratonic basin which received great thicknesses of Permian sediments. The area was exposed during the first two periods of the Mesozoic era. The Cretaceous sea moving up from the south marked the last marine transgression. Late Tertiary uplifts accompanied by faulting preceded the deposition of Quaternary alluvium