Methanophage sulfate-reducing bacteria have played a very similar role in association with methane seeps through Permian evaporites in west Texas and New Mexico. Sulfuric acid (from oxidized hydrogen sulfide) is believed to have been the principal agent responsible for creating Carlsbad Caverns and the related Lechugilla cave system. This includes the associated gypsum deposits and stunning cave formations in Lechugilla. The down-dip components of the Permian hydrologic system can be seen in the Gypsum Plains area of Culberson County, Texas. Here, methane seeps, some still active, are associated with calcitized Castile Formation evaporites, complete with characteristic well-preserved disharmonic folds, and with native sulfur, H₂S gas and patches of extremely coarse secondary, hydrothermal? selenite gypsum. Selenite crystals may be several feet in diameter.

Some outcrops appear to represent a calcitized facies of the Salado Formation, which over-lies the Castile Formation. The Salado secondary carbonates include botryoidal cements, which suggest that early bacterial precipitation may have taken place at or near the very late Permian sea floor. Methane seepage is suggested to have occurred over a geologically long time interval.