Virtual Field Trip—Group 7
Geologic Overview of Fort Stanton Cave
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Fort Stanton Cave is located in the Sacramento Mountains and consists of San Andres limestone. The San Andres limestone covers most of southeast and southcentral New Mexico. The GPS location of the cave entrance is 0454249 South, 3707371.
Geologic Background
Fort Stanton is located on the south side of Hwy–380, about midway between Lincoln and Capitan, New Mexico. The entrance, at an elevation of 6,160 feet above sea level, is about a mile off of the highway, it is a steep-sided sink hole. This cave is the third longest cave in New Mexico and the most extensive cave in the Sacramento Mountains. The cave is made of San Andres limestone of the Permian age (~300–240 m.y.). The formation of the cave is the result of erosion by an underground stream and the dissolution of limestone by carbonic acid. The cave is of special interest because of speleothems (secondary mineral deposits formed in caves).
- There are two major types of speleothems: Calcium carbonate based (limestone) and calcium sulfite based (gypsum crystals).
- Some examples of calcium carbonate speleothems would be: soda straws, fried eggs, and cave velvet.
- Examples of calcium sulfate or selenite crystals would be: selenite needles and gypsum stars.