Day 4 : Stop 4

DAY 4 (9/29/2025) - STOP 4

"Parks' Ranch Cave System"

COORDINATES: 32.11084° N, 104.40636° W

Fig. 35 Gypsum / Evaporite Beds on Cave Walls

    We next visited two caves, located within the Parks Ranch Cave System (fig. 36), that sit within the gypsum-dominated evaporite succession of the western Delaware Basin. These caves are found in Permian Castile evaporites. The Castile Formation creates thick and lateral beds of gypsum and anhydrite (fig. 35) that were deposited during the Late Permian in a deep, restricted basin where the concentration of seawater produced an evaporitic sequence. The laminations and laterally continuous beds preserved in the Castile record deposition below the wave base in a hypersaline depositional setting. These primary lithologies, gypsum and anhydrite with intercalated carbonates, provide both the soluble substrate and structural fabric that control modern karst development in the area (Stafford et al., 2008).

    Field observations at the Parks Ranch system and in other gypsum karst landscapes emphasize rock-type controls on depositional and post-depositional behavior. Gypsum and anhydrite dissolve at rates far greater than carbonate rocks under the same chemical conditions, which explains the abundance of solutional depressions and rapid enlargement of conduits during high-discharge events. The cave system itself, mapped to more than four miles of passages with multiple entrances, narrow crawls adjacent to larger galleries, domal or breccia zones where intrastratal dissolution and collapse have occurred, and depositional features, such as sands, clay, and standing water, that record surface inflow and local ponding during storm events (Bureau of Land Management, 1993). This was especially prevalent during our visit to this site because the area had been recently subjected to heavy rainfall. This resulted in flooding and still water in the system.     

    The geology and geomorphology of the Parks Ranch site show an evaporite-karst system where depositional history, lithologic susceptibility (gypsum/anhydrite), structural and stratigraphic architecture, such as continuous laminations and bedding contacts, combine to produce an extensive cave network and a dynamic surface karst landscape.

Fig. 36 Walking Through Park Ranch Cave System

External References:
Stafford, K., Rosales-Lagarde, L., & Boston, P. (2008). CASTILE EVAPORITE KARST POTENTIAL MAP OF THE GYPSUM PLAIN, EDDY COUNTY, NEW MEXICO AND CULBERSON COUNTY, TEXAS: A GIS METHODOLOGICAL COMPARISON. https://legacy.caves.org/pub/journal/PDF/v70/cave-70-01-35.pdf

Parks Ranch Cave System. (1993). Bureau of Land Management. https://www.blm.gov/sites/default/files/docs/2023-06/Parks_Ranch_Cave_System.pdf