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Going Underground (Carlsbad Caverns NP)

Updated: Nov 17, 2022

Friday, 4 November 2022, Carlsbad

You can tell a lot about a place from its name. Looking at NPS sites, you have Mammoth Cave NP. Wind Cave NP. Oregon Caves NM. Timpanogos Cave NM.

Carlsbad CAVERNS NP.

Most caves are formed by rainwater sinking into the ground, dissolving limestone. This water seeps through fractures and sinkholes, feeding underground streams, which carve out passages reminescent of subway tunnels (as one ranger put it). These caves tend to run horizontally (though often at different levels).

Only 2% of the caves in the world (including Carlsbad) were formed from sulfuric acid. Millions of years ago, when the future cave was at the water table, water rich in hydrogen sulfide migrated through fractures in the reef that now forms the Guadalupe Mountains. This water mixed with rainwater to form that acid. The gas from this acid coated the limestone ceiling of any opening, turning it into gypsum (the same material in drywall). Soon these rinds of gypsum would succumb to gravity, falling into the pools and dissolving. The acid would then coat the newly-exposed limestone, turning it into gypsum, and the practice repeated itself for eons.

This process created the aptly named Big Room in Carlsbad: nearly 4,000' long, 625' wide, and up to 255' high. This space - the word 'cavernous' comes to mind - exceeds any other chamber in North America, but ranks 'only' 31st in the world. The Big Room is set up for self-guided tours, but the King's Palace can only be toured with a ranger.

When I reached the park at 10:00, I headed straight to the ticket booth for the 'first come, first served' tickets for the King's Palace cave tour. Timing! I got the last ticket for the day. Nice to start with a 'win'.

Last night I'd reserved a ticket to see the Big Room, to enter between 9:30 and 10:30. This main attraction lies 750' underground, thus many people opt to take the elevator down (and back up later). The more adventurous visitor can instead go in the natural entrance (at the Bat Flight Amphitheatre)

and descend 750' on a one-mile walk. Guess which option I chose!

The natural entrance gave off a spooky vibe, with diminishing light the further in I went. The twilight zone ended quickly,

and all light now came from electric lights. (Fun fact: in 2017, the NPS replaced the existing lights with LED bulbs, which provides a more natural light.)

This upper part of the cave had few speleothems (cave features such as stalactites and stalagmites). I did notice helictites on the ceiling early on,

but other features had to wait for the 45 minutes it took me to reach the Big Room. Once at the Big room, I marveled at the highlights:

Though I have toured many caves, I don't recall every seeing spongework, formed when porous rock had its pores enlarged by the sulfuric acid.

A feature unique to Carlsbad is the Lion's Tail - easy to see how this got named! Calling it 'Cave popcorn on the end of a stalactite' doesn't have the same romance.

Cave drapery I've seen in many caves, and Carlsbad has several examples. Instead of water dripping to form a stalactite, it flows down a sloped ceiling, depositing calcite that forms a curving sheet. Some drapes with dark and light bands have earned the name 'cave bacon'.

(NPS has placed many interpretive signs along the trail, describing the features and talking about the park history. One sign mentioned that in the 1930s, someone floated a proposal to dynamite through a cave wall to make the area accessible to autos. In a milk bottle full of bad ideas, that would certainly be the cream rising to the top! Thankfully, the notion went nowhere, and soon after the NPS added the elevators. But nature is complex! and adding this access lowered the humidity, causing the cave to dry out. In the 1970s, they added airlocks at the elevator to mitigate that damage.)

The Silent Bell is a stalagmite with a twist: while forming, the base of the stalagmite sat next to a pool. The feature continued expanding, but the part extending over the pool stopped when it touched the water. Today the water is gone, and the rim of the stalagmite perches over air - resembling a bell that can never be rung.

This distinctive stalagmite was dubbed Rock Of Ages. When I first saw it (before knowing its name), I called it the Walrus. Coo-coo-ca-choo!

Flowstone occurs when water flows over a surface, instead of dripping. Some flowstone features look like 'frozen waterfalls'.

I passed a few pools along the trail. If you look closely, you can see ripples in the water, caused by drips falling into the pool.

This whimsical feature got dubbed the Chinese Theater. Some people say it looks like a pagoda.

After two and a half hours, I finished my self-guided tour. Time to retire to the cafeteria/gift store/elevator/restroom area for a snack and to rest before the 1:30 King's Palace tour. More information on the cave is displayed there. Fun fact: every year, volunteers remove 19 pounds of lint (such as clothing fibers, skin cells, hairs) from the cave. [It would certainly be far more than that if the NPS hadn't banned all food products (other than plain water) from the cave.]

Before taking his visitors into the King's Palace (853' underground, lower than the Big Room), the ranger showed that his tour would be highly interactive. He started by asking everyone in turn to name their favorite National Park. (I declined to name one, saying I wouldn't finish seeing them until next fall.)

Once in the lower cave, the ranger started by pointing out the Royal Family (seen just right of center near the bottom) - not sure if I can see the resemblance...

As part of his patter, talked about changes to the caves - electric lights, hand rails, paved trails - and how they affect the cave environment. He posed a question to the tour group: "Can you name a time when you altered your environment? What happened? What changes did you notice?"

I had to weigh in. "When I was in the 5th grade, we lived on seven acres out in the country, and an irrigation ditch ran through our property. One day that spring, my brother and I got the notion to build a dam in the ditch, see how the water flow changed. Scientific curiosity, right? The farmers downstream were NOT amused."

After a few more answers, he moved the group into the actual King's Palace area. This area sparkled with stalagmites, stalactites, and drapery.

As he held us back so people could take photos, he posed another question. "Sometimes change can happen naturally - for instance, erosion could break off a rock and send it off a cliff. Or a person could throw a rock off a cliff. What is the difference between natural and man-made change, if both types result in new rocks off the cliff?"

Guests answered by equating 'natural' with 'random or chaos', and man-made as 'logical or intentional'. I raised a different issue. "Man changes the environment to suit himself. But how about a beaver? He alters the environment to achieve his needs by building dams. Is that considered natural?" [Ooh... maybe I have a latent fetish for dams that's finally coming to light...] The ranger conceded my point.

The last major room in the tour was the Queen's Draperies. Here, many drapes undulated across the room, though they were difficult to frame in a photo.

As we paused in this room, the guide resorted to the basic trick in a cave guide's repertoire: turning off the lights so people can feel the effect of total darkness. "Now, most people will have one of two reactions to 100% darkness: either abject terror, or thoughts of, 'Man, I could get the best night's sleep of my life here!'"

Before leading us up to the exit (with the lights back on!), he asked the group one last question: "What will you take from the cave today?" He was obviously fishing for notions like 'inspiration' or 'a sense of awe'. However, one young girl beat everyone to the punch. "Nothing!" she cried out, pleased with herself for knowing not to disturb anything here.

On the way back to the Big Room, we passed through the Green Lake Room. The (greenish) reflection in the pool impressed me.

Back on the main trail, the ranger gave us our options: we could take the elevator 750' back up to the Visitor Center, and take the natural-entrance trail back for a mile, at an average gradient of 20%. I've always said I may be crazy, but I try not to be stupid. I took the elevator.

Driving out the park road, I stopped at two pullouts and took short walks into the surrounding Chihuahuan Desert. The display at one pullout made a claim that surprised me: this desert (one of four in North America) contains the greatest biological diversity in the world. It has more reptiles than the Sonoran Desert, more bird species than the Everglades (!!!), 130 mammal species, and over 3,000 plants. Amazing! Especially considering how desolate it feels.

I looked at the time: nearly 5:00. Nothing to hurry back to town for... so let's head back for the bat flight. This time I stayed away from the cave entrance - close-by cameras may distract the bats as they strive to reach cruising altitude, but a camera far away from them shouldn't cause a problem.

I noticed fewer bats than the night before, but still saw a few bat-clouds fly by. I can't imagine seeing over a hundred times as many on the wing...

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