Carlsbad Caverns National Park

The caverns started forming about 250 million years ago. The area was under water at the time. The land around the sea was a flat plain with higher hills in the northwest and southwest. The climate was warm. Near the shoreline of the inland sea small forms of lime-secreting algae found a home in the shallow offshore waters. Generations of algae lived off the husks of the previous ones. The lime built up until the reef-like mass was several hundred feet high and at least a mile across. It dipped sharply into the deeper water at the face. Behind it the waters were shallow and protected from the sea's turbulence by the rocky wall. This back reef area varied from a width of one to a dozen or so miles. The top of the reef was near water level and was usually awash. Many forms of sea life lived on it. This reef, today called the Capitan Reef, was made of algal remains and fossils of sea life.

The reef formed a natural barrier between the lagoon waters toward shore and the open sea. As steams and rivers emptied into the lagoon, they emptied sediment from the highlands into this back reef area. Sediments on the seaward side were very different. But under the pressure from waves sediments and the reef itself continually broke off spreading "reef talus" several miles out to sea. The reef pieces were deposited in layers with mud and sand brought in by sea currents

Later the channel supplying water to this inland sea began to close off. The sea became stagnant as water evaporated. As salty water evaporated gyspum and salts filled the basin over the next few centuries. It was now almost a flat surface again with the reef hidden below. Millions of years passed of sediments being deposited above the former reef. Several thousand feet of sediment were deposited. Then about 60 million years ago the region was lifted and changed from its previously low lying position. It was tilted at a low angle with the higher area to the west. As the crust lifted, erosion tore down the higher areas. The uplifting was gradual and uneven. About 25 million, more movement occurred, to raise the previously low lying reef several thousand feet above the former sea level. Erosion wore down the salts, gypsums, ands, and shales at about the same rate as the uplift. But the reef and some of the back reef limestones were more resistant and uplift was faster than erosion in the area of the Capitan Reef and its lagoon deposits. So the Guadalupe Mountains began to take shape because of the resistance of the limestones. The south face of the Guadalupes is the edge of the ancient algal reef. Most of the reef lies buried in New Mexico and Texas, but it has been traced for hundreds of miles by drilling.

As the original reef was buried stresses and strains of the overburden caused the first hairline fracture within the reef. Movement of the earth's crust added more. Ground water entered the reef limestone through these cracks. Gravity carried the water down the water carried tiny amounts of chemicals from the soil and humus it passed through causing it to become a weak acid. This weak acid dissolved the limestone. Where the limestone was dissolved the limestone was carried away by moving ground water. Cavities enlarged. The dissolving was greatest at or near the ground water level since newly supplied acidic ground water had not yet been diluted or neutralized at that point.

When the Guardalupe Mountains were exposed by erosion, the water table in the area around Carlsbad Caverns dropped. The water slowly drained away. A lower level evolved and stabilized. While the water was within the spaces it supported the lattice like network of openings. As the water drained away some of the unsupported rock collapsed and created the great chambers known today. Some did not collapse however and can still be seen today, such as in the section called The Boneyard. At three levels the water stood for some time resulting in nearly horizontal cave levels at about 200, 750, and 850 foot depths.

As soon as a chamber became partially air filled, changes began. Waters from rain and snow filtered through the soiland humus where it picked up CO2 and became a weak acid. It dissolved limestone while moving through and carried the dissolved limestome away. But because this is now an ir fille dchamber rather than a water filled one, the water formed dripson the ceiling or wall. At that point the CO2 was released into the air. At that point the water is no longer acidic and could no longer carry the limestone in solution. The limestone would drip out and cling to the ceiling or wall. These would be stalctites. If the water was flowing too fast to deposit the limestone it would fall to the floor and deposit the beginning of a stalagmite. Sometimes limestone is deposited in both places.

Radiocarbon dating shows bats have been in the cave about 17,000 years. There were two known natural openings. The trail for the walk in tour goes through the large natural opening. The second one is about one quarter mile east of the first and is a narrow rift with a vertical drop of over 100 feet into the portion of the cave known as Bat Cave. Many species of bats are here but the most common are the Mexican Freetail Bat (Tadarida brasiliensis). It spends about half its life in Mexico. The colony rests about a one quarter mile east of the main entrance near the small rift of the second natural opening. Public trails do not go there. The bats use the people entrance to enter and exit however. When in the cave they hang upside down at an average of about 300 per square foot of ceiling. They come up in a counter-clockwise spiral at the rate of 5,000-10,000 bats per minute. They return individually. In the 1940s the colony at the caverns was in the several millions. The decline is due to use of pesticides by farmers that reduce their food supply. Some were poisoned themselves. But because of the bats man first became interested in the caves.

Unusual formations called helictites grow in all kinds of directions. Many look like the underground view of a root system of a plant. They contain a tiny central canal through which water moves. The conduit and end openings are so small that a speck of water on the tip will not form a drop. Cave Pearls are common in Carlsbad. Dripping water must fall with enough force and flow to hollow out a small depression in the floor. Any small foreign object that falls into the depression becomes the nucleus of a pearl if enough water comes down. Constant agitation of the water coats the nucleus with layers of limestone.

Earliest occupants of the Guadalupes area was about 12,000 years old. Artifacts have been found associated with the musk ox and four horned antelope. Other remains about 4,000 years old have been found, attributed to a little known people called the Basketmakers. They were here until about the 13th century when the Apaches either drove them away or absorbed in them in their own culture. After that we lose all traces of the earlier tribes. The Apaches remained until fairly recent times and were there when early American military epeditions of the middle and later 1800s came through. Then they were driven from the land. Their descendants now live on t he Mescalero Apche Reservation 100 miles norrthwest of the caverns. They didn't venture far into the cave; there is a 30 foot drop off just inside the natural entrance and an Indian sandal was found there by early explorers. Spanish explorers came into the area in the 1500s but there is no evidence they entered the caverns region. When the area became part of Mexico in 1821, then the U.S. got the land by the Treaty of Gaudalupe Hidalgo and in 1850 established the territory of New Mexico.

After that homesteaders came in and started up ranches. They were the ones that refound the cavers and other caves. The name Bat Cave was given to the big hole that would later become famous. One of the earliest explorations into Bat Cave was in 1883 when a 12-year old boy named Rolth Sublett of Artesia, New Mexico, was lowered into the cave by his father. He only went as far as natural light carried. Two years later Ned Shattuck and his father were searching for a stray cow and saw bats flying out. Many neighbors figured there must be large amounts of nitrate-rich bat guano that would be good vertilizer. In 1903, Abijah Long filed a claim for guano and other minerals on a 40-acre site around the mouth of the Big Cave. Other guano claims were filed too.

Mining started soon after. Shafts were dug into bat cave and mine cars used to transport it to the surface. Over a period of time six companies tried to make a financial success of guano mining. All failed largely to high transportation costs. Still in 20 years of operation over 100,000 tons of guano were taken out. Most was shipped to southern California for the citrus industry. Mining stopped in 1923, but some brief activity occurred in the 1940s. Few of those early miners had the curiosity or the bravery to explore any of the rest of the caverns. James Larkin White was the exception. He had worked for most of those mining companies. In his spare time, he took lanterns and probed deeper. In 1922, the stories attracted the attention of Commissioner William Spry of the General Land Office. He began an investigation of the cave to designate it a national monument. Mineral Examiner Robert A. Holley was assigned the task. On October 25, 1923, President Calvin Coolidge designated Carlsbad Caverns National Monument. In the late 1920s trails were built and lighting was installed. Exploration continued while only parts were open for public tours. New passages were discovered in 1966. It received national park status in May 14, 1930, when President Herbert Hoover signed a bill creating Carlsbad Caverns National Park. The first two elevators came into service in 1931. Two more awere added in 1955. The present visitor center was dedicated in 1957.

There are some 27 other known caves outside of Carlsbad and many others in the Guadalupes not within the park. Many contain the formations that Carlsbad does. New Cave on the wall of Slaughter Cavern is one of the larger ones. Guano was mined here until 1957 when the fed government acquired the land and made it part of the national park. Some scenes from the movie King Solomon's Mines were filed in New Cave. Lechuguilla Cave, near the caverns, is the deepest and one of the longest caves in north America. It is 1,567 feet deep and 89.3 miles long. It is dark has steady temps, limited air circulation, little water and almost no organic matter. There are about 1,200 microbial life forms, some that are found no where else on earth. It has no bags or insects so there are no organic residue to feed organisms. There is no flowing water and only one known passage to the outside world. Many of the unusual bacterial feed on and get energy from "eating" iron, manganese, and sulfur. On the surface are prickly pear, mescal, sotol, rock squirrels, rabbits, skunks, racoons, gray fox, bobcat, porcupine, raing tail, diamond back rattler, black tailed rattler, roadrunner, black chinned sparrow, rock wren, Say's phoebe, nighthawks, cave swallow strawberry cactus, pitaya, yucca.

Modern tours go 829 feet below the surface on steep switchback trails as you wind through the Main Corridor, Green Lake Room, Kings Palace, Queens, Chamber, and Papoose Room. Average temperature is 56 degrees year round. During the evening in the summer a bat flight program is given at the natural entrance. Roadside exhibits, developed nature trails, and primitive hiking trails lead into the backcountry.

Go back home

Last revised 5/19/98