Lechuguilla Cave

Situated in Carlsbad Caverns National Park in New Mexico, Lechuguilla Cave is the deepest limestone cave in the United States and one of the longest caves in the entire world. Throughout the cave’s history, adventurers have mapped in excess of 136 miles of passages in the cave and descended to a depth of 1,604 feet (with unknown depths still to explore), ranking Lechuguilla among the longest caves in not only the United States, but also the world. The cave, which received its name from a plant species called Agave lechuguilla that was present near the entrance, is a complex, winding maze that is still not fully explored or charted. The cave is renowned for its uncommon geology, including formations seen nowhere else, and its largely undisturbed condition. In 1993 the US Congress passed legislation protecting some ten square miles, or about twenty-five square kilometers, around Lechuguilla Cave.

Background

Until 1986, Lechuguilla Cave was considered to be a small and rather unimportant historic site within the Carlsbad Caverns National Park. Under a mining claim filed in 1914, small quantities of guano (bat excrement) had been mined from the cave opening area, which was known as Misery Hole. Early exploration of the cave showed it to consist of a pit dropping about ninety feet, followed by about four hundred feet of passages with no outlets or underground waterways. After the mining operation ended the cave was visited infrequently, mainly by cave enthusiasts. Yet a group of visitors in the 1950s noticed a wind current coming from the bottom of the cave, leading many to believe that further passages must exist but had been blocked by a cave-in. In the 1970s there were a number of efforts to break through the collapsed rubble, but they were unsuccessful.

In 1984 a group of cavers from Colorado got permission from the National Park Service (NPS) to dig in the cave. That team finally broke through into massive passages on May 26, 1986, and subsequently began to explore what proved to be a vast network of interconnected chambers. Lechuguilla soon proved to be among the longest and deepest known caves—greater even than its more famous neighbor, Carlsbad Cavern—and revealed extremely well-preserved examples of rare and never-before-seen formations. Ever since, cavers from around the world have come to help map the cave and study its unique geology.

The extensive nature of Lechuguilla Cave means that even after years of exploration it remains incompletely mapped, with its ultimate dimensions unknown. Expeditions continued to push the known limits of the cave into the 2010s. In 2012, a team directed by caver Derek Bristol explored the top of a dome within the cave and uncovered a number of unexplored passageways, pits, and even big rooms. The new portion of the cave was named "Oz," with several of its features named in reference to L. Frank Baum’s book The Wizard of Oz, including an expansive room called Munchkin Land and a deep pit called the Kansas Twister. Bristol and his team took over a week charting Oz, and their findings pushed the cave’s overall length to over 130 miles.

Overview

Lechuguilla Cave lies within an ancient coral reef–turned–mountain range, the Guadalupe Mountains, which straddle the Texas-New Mexico border. The cave is essentially a vast maze of large rooms and galleries, narrower channels with deep pits, and slotted rifts. Many of these features are thought to have formed as vents for rising fluids that migrated through the limestone of the former coral reef long after it had been buried by other sediment. After mixing with oxygenated groundwater or interacting with air at surface of the water table, the fluids developed sulfuric acid and essentially dissolved the large chambers. This process likely happened when the Guadalupe Mountains became sloped in the late Tertiary and Quaternary periods. The geology of Lechuguilla suggests that the cave built itself from the bottom up, rather than the top down.

Lechuguilla Cave is deep and insulated from surface water and air by its relatively small entrance and the solid siltstone rock above it. Because of this, temperature in the cave is cooler in the deeper points. The airflow and convection patterns caused by this variation is thought to have played an important part in developing the unique patterns of deposition and erosion that created the cave’s exquisite mineral formations, or speleothems. These include vast quantities of brightly colored gypsum and sulfur deposits in the form of so-called chandeliers, straws, beards, and hair. Other features, some of which are unique to the cave, include cave pearls, rusticles, "balloons" of hydromagnesite, and subaqueous helictites. The speleothems of Lechuguilla Cave are even larger and more varied than those found in Carlsbad Caverns. There is a close connection between the cave and the local aquifer system; the lower-most pool in Lechuguilla, called the Lake of the White Roses, is believed to intersect the water table in the Capitan Reef Aquifer that supplies water to the region.

The discoveries made in Lechuguilla Cave include rare bacteria classified as chemolithoautotrophic, or rock-eating, and which live off minerals such as iron, sulfur, and manganese. It is hypothesized that such bacteria may have played a role in creating the cave’s massive size and the unique assortment of speleothems. Another discovery made in the cave is the extremophile microbes that may have medicinal benefits for human use.

Lechuguilla Cave was recognized as unique and important by the US Congress in 1993, and the cave itself and surrounding lands are protected from development. However, the park wilderness area is next to land owned by the Bureau of Land Management (BLM), which allows drilling for oil and gas resources. The proximity of drilling activities increases the risk of the cave being breached by fluids or gases, which could disrupt the cave’s delicate ecosystem, destroy unique features, and potentially make the site unsafe for further exploration. The National Park Service actively works to protect the cave and minimize risks. For this reason, access to the cave is restricted to authorized researchers, surveyors, teams of scientific explorers, and National Park Service personnel. Though no tourism is allowed in the cave, several film crews have documented some of Lechuguilla Cave’s features for various productions.

Bibliography

Culver, David C., and William B. White. Encyclopedia of Caves. 2nd ed. Boston: Academic, 2012. Print.

Davis, Donald G. "Extraordinary Features of Lechuguilla Cave, Guadalupe Mountains, New Mexico." Jour. of Cave and Karst Studies 62.2 (2000): 147–57. Print.

Jagnow, David H. "The Geology of Lechuguilla Cave, New Mexico." Subsurface and Outcrop Examination of the Capitan Shelf Margin, Northern Delaware Basin. Paul M. Harris and George A. Grover, eds. Tulsa: Soc. of Economic Paleontologists and Mineralogists, 1989. Print.

"Lechuguilla Cave." Carlsbad Caverns. Natl. Park Service, 2016. Web. 1 Sept. 2016.

Taylor, Michael Ray. "Journey into Lechuguilla Cave." NOVA. PBS, WGBH, 1 Oct. 2002. Web. 1 Sept. 2016.

Waltham, Tony. Great Caves of the World. London: Natural History Museum, 2008. Print.