An early meetup with Joy and Larry and drive up the 7-mile road to the park headquarters to begin our visit. Day 3 was a two-event day with a morning hike and exploration down into the caverns and later in the day, a ranger guided tour into the Kings Palace and an elevator ride out.
The following description of the geology of the caverns is extracted from a USGS description of the park.
The area where Carlsbad Caverns is located today was the coastline of an inland sea 250 million years ago. Due to the warm, shallow, tropical seas, the reef formed from mostly sponges and algae instead of coral, like many reefs today. Landward of the reef redbeds, evaporites, lagoonal mudstones, pisolitic grainstones (calcium carbonite grains that build on each other looking like tiny onions), and back-reef grainstones were deposited during this time period. Today, the reef deposit makes up the Capitan Limestone formation, which is 750 feet thick, and most of the National Park is within this limestone formation. Eventually, by the end of the Permian (approximately 251.9 million years ago marked by the largest mass extinction of life in earth’s history), the sea dried up and the reef became buried by sediment for tens/hundreds of millions of years. Fossils from this time period can be seen within Carlsbad Caverns, including ammonites, crinoids, snails, nautiloids, bivalves, brachiopods, and trilobites.
Over the past 20 million years local faulting and stresses of the Earth’s crust uplifted the reef sediment by nearly 10,000 feet, creating the Guadalupe Mountains to the south southwest. The sediment eroded, exposing the reef. Within the Guadalupe Mountains there are more than 300 caves, and 119 known caves within Carlsbad Caverns National Park. The Big Room in Carlsbad Caverns is the largest cave chamber in North America, with 8.2 acres of floor area. Additionally, Lechuguilla Cave is the deepest and third-longest cave in the United States.
The caves in Carlsbad Caverns are unusual, as they formed from sulfuric acid instead of carbonic acid. Most caves in the world are formed when water interacts with carbon dioxide and seeps downwards. The location of the Guadalupe Mountains played a key role in the creation of these caves. Carlsbad Caverns National Park is located near the border of New Mexico and Texas, and close to the Permian Basin, which hosts large oil fields. Hydrogen sulfide-rich water rose from the oil reservoirs as late as 12 million years ago and mixed with groundwater to form sulfuric acid. The limestone was dissolved at the water table, and therefore, Carlsbad Caverns was dissolved from below and not from above. Gypsum blocks, a byproduct of sulfuric acid dissolution, can be seen today on the floor of the Big Room of the Carlsbad Caverns.
So, there you have it. More interesting to me was the concept that at some point in time each level of the caverns represented a relatively stable water table. As the caverns were formed, and the uplift of the area continued, there was beyond a significant amount of free-standing water in the caves. All those years when the water dousing guys came around looking for the underground rivers and lakes to drill into for water supply had some bit of rationale. If only there had been a limestone bed in the area!!
The park was not crowded at all during our visit. After going through the visitor center, we hiked down through the natural entrance to the cave and dropped 750 feet on a 1.25 mile relatively steep switchback trail. As we dropped down the temperature dropped to a chilly 56 degrees F, all light was provided by artificial means, and it got very quiet. Lots to see and appreciate.
The second part of the day was a guided tour into the King’s Palace portion of the park with Ranger Rick. This area is only open to ranger guided tours because there are no railings to keep morons from destroying the cave. It is a phenomenal area of the caverns to visit, and Ranger Rick knew his stuff including geology, archeology and history of the area. At one point, he did the obligatory turn off of all the lights for a bit so that we could appreciate what it took to explore the caves back in the late 1800’s.
The photos that accompany this post are primarily from Joni’s iPhone. I found that while my camera gave realistic photos with lighting and color, the iPhone did a far better job of making the caverns wild and crazy features and topography visible. Also, apologies for lack of scale in many of the pictures. The dark doesn’t provide much opportunity for distance comparisons. Moreover, the railings and controls to keep Moron Assholes Generally Americans from ruining the cave features does not allow up close warm and fuzzy approaches to the features.
