EVAPORITE KARST SPELEOGENESIS OF EDDY COUNTY, NEW MEXICO

Guadalupian and Ochoan evaporite strata of the Permian Basin in Eddy County, New Mexico are heavily associated with extensive, widespread karst development. Various speleogenetic processes influence the variety of karst features evident here. Caves formed by dissolution of rising fluids due to both forced and free convection are numerous within the study area; these hypogene caves are traditionally associated with isolated subsurface voids and maze caves and can be easily recognized by morphological features including risers, cupolas and half-tubes. While hypogene processes are the most prominent mechanism for speleogenesis, open and filled depressions in the form of sinkholes are the dominant karst geomorphic manifestation; however, a thin gypsum crust exists over most areas while exposed bedrock features exhibit heavy karren development. Within many well-developed sinkholes, epigene caves commonly exist, forming large, incised openings connected to small solution conduits. Evidence of paleokarst features may be found at K Hill, a paleokarst erosional remnant formed by post-Cretaceous collapse of overlying rock into a karstic void that had previously developed within the Castile formation, as well as other locations. Varied expressions of brecciated zones are yet another prominent karst manifestation, including vertical breccia pipe structures and lateral blanket breccias, which have been documented throughout the Delaware Basin related to the Castile, Rustler and Salado formations. Basalt dikes and hydrogen-sulfide rich springs within the study further complicate the speleogenesis of the region.