We solicited suggestions for things to do in the Southwest a few weeks ago and a number of folks suggested we check out Carlsbad Caverns National Park in southern New Mexico. Because we like caves, and it was along our route, we gave it a go.
It turns out Carlsbad Caverns National Park contains more than 110 natural limestone caves, but we only had time to explore Carlsbad Cavern itself (which, having been dissolved by sulfuric acid only a measly 4 to 6 million years ago, is apparently one of the newest caves in the Guadalupe Mountains).
After taking an elevator down hundreds of feet we found ourselves in a huge (on average it takes about an hour and a half to circumnavigate) cavern and set off on a winding, paved trail lined with guardrails (this becomes important later!).
The cavern was massive, with strange rock formations jutting from the ground and long rock spires decorating the ceiling. There were strategically-placed lights all throughout the cavern to highlight the formations, but they were very dim and oddly-hued so even with a tripod it was difficult to take quality photos.
Most of our walk was uneventful, until…
As we were gazing into the Bottomless Pit (it’s not actually bottomless, but it is pretty darn deep) we cracked a joke about how awful it would be to get stuck down in the caverns in the dark. We had just read a sign explaining that all lights are on a back-up generator because without them it would be PITCH BLACK in the cave.
“Whew!” we laughed. “I’m glad there’s a back-up system in place, because we didn’t even bring our cell phones, let alone a flashlight. How would we get out of here?”
Cue the darkness.
No, seriously, cue the darkness. All of a sudden, out of nowhere, the lights just went out! Uhm…. helloooooo?
I swear there had been people around us not even ten minutes before, but now it was deserted and we seemed to be the only ones stranded in a really, really dark cave.
In fact, as the quiet darkness settled around us it was easy to believe that maybe we were the only ones left in the whole world, and some catastrophic nuclear event had wiped out humanity as we knew it — along with our backup power — on the surface (this seems farfetched now, but at the time…).
I remembered passing a safety phone a little ways back (we’d made fun of it because it said Cave Watch! and urged us to call the operator to report any shenanigans taking place), so we grabbed ahold of the guard rail and groped our way in the direction we’d come.
We used the LCD screen on our camera to find the phone and dial, then spoke with a cheery operator who, apparently somewhat surprised to be getting a call from underground, asked to put me on hold. ON HOLD?!
I’m practically being eaten alive by bats down here and I’m terrified no one will ever find my remains and you want to put me on HOLD?!?
Okay, in reality we were actually pretty calm. Sure, on the inside I was secretly envisioning the next day’s tourists stumbling over my scattered bones, but we kept our panic at bay and entertained ourselves by placing bets on how far we could get in the dark before we fell into a bottomless chasm.
Eventually the operator returned and told me a ranger was on his way down to rescue us with a flashlight. Long story short, it turns out there hadn’t been any nuclear explosions (I know, you were all really worried about that, huh?) — instead he had just TURNED OUT THE LIGHTS for the evening after doing a walkthrough and determining that the cave was empty.
Empty? Y’know, except for those two pesky tourists (that would be us) who happened to still be in there.
It gave us a good fright, but it also gave us a good story… and the resolve that next time we enter a cave we’re bringing enough flashlights to light the whole damn thing if we have to.
There are more photos of the caverns below, with geological descriptions (for our rock-obsessed family members) that I more-or-less lifted from the official Carlsbad Caverns National Park website. Enjoy!
The cave was dissolved along cracks and faults in the limestone rock by sulfuric acid.
The limestone was laid down about two-hundred and fifty million years ago, as part of a reef complex along the edge of an inland sea. Seventeen to twenty million years ago, the ancient reef rocks that had been buried under thousands of feet of younger rocks began to lift upwards. Tectonic forces pushed the buried rock layers up and erosion wore away softer minerals to expose the ancient reef as the Guadalupe Mountains. Deep in the basin, a brine originating from oil and gas deposits and rich in hydrogen sulfide was forced into the limestone at the edge of the basin. When this brine encountered oxygen-rich rainwater moving down through the rock, it created sulfuric acid. This acid dissolved the limestone creating cave passages. As the Guadalupe Mountains continued to lift up, the water drained out of the cave allowing fresh water to percolate through and leave minerals on the ceiling, walls, and floors that we know as cave decorations.
The speleothems (cave formations) that decorate Carlsbad Cavern are due to rain and snowmelt soaking through limestone rock, then eventually dripping into and evaporating in the cave below. Those water drops have absorbed gasses and dissolved minerals from the soil and limestone above. Wherever that water drop evaporates and releases carbon dioxide in an air-filled cave, a small amount of mineral (mostly calcite) is left behind. Thus, drip-by-drip, over the past million years or so, Carlsbad Cavern has slowly been decorating itself.
Most of the speleothems found inside Carlsbad Cavern were active and growing during the last ice age when instead of having a desert above the cave, there were pine forests.
Common speleothems found on the ceiling may be stalactites, soda straws, draperies, ribbons or curtains. The faster the dripping, the more likely it is to make some type of decoration on the floor. A wide range of decorations on the cave floor include totem poles, flowstone, rim stone dams, lily pads, shelves, cave pools, and of course stalagmites.