Sunday, October 22, 2017

How Does a Pristine Cavern Look? Black Chasm Provides a Clue

Some things can only be experienced once. The discovery of a new plant or animal that no one has ever seen, a new mineral, a new planet in space, to see a vista that no one has witnessed before. Exploration of new things is one of the great joys of being human. One of the saddest lines I've ever seen in a move was from The Truman Show (1998):

Young Truman: I'd like to be an explorer, like the great Magellan.
Teacher: [rolling down a map of the world] Oh, you're too late. There's really nothing left to explore.
Entrance room of Black Chasm cave. The dirt on the decorations is from soil seeping in from above, but many of them are broken from early explorers and visitors.

And there are things that can be destroyed only once. The extinction of a species, a beautiful canyon marred by a poorly-planned development, the destruction of a culture or a people.
If there is anything I have learned as a scientist and a teacher, it is that there is never an end to exploration. I was reminded of this as I took a group of students on a field studies journey on Saturday. Ostensibly the trip was about caverns and karst topography in the Sierra Nevada Mother Lode, although it included a great deal of information about the 1848 Gold Rush as well. We toured Highway 49 between Jackson and Columbia, but included an excursion through Black Chasm Cave near the village of Volcano.
Helictites in Black Chasm Cave
So many caves that are known today were discovered in previous centuries, and have been explored and vandalized to a shocking degree. My opening point about a single moment of discovery and a single final moment of destruction applies in many ways to caverns. A cavern can only be discovered and explored once. From that time on, in human terms, it is moving inexorably towards destruction. Caverns cannot recover from the damage inflicted by human visitors in any kind of time frame that people would recognize.
Helictites in Black Chasm Cave
Non-cavers are often confused or bemused by the nearly maniacal lengths that cavers take to prevent causing damage to pristine caves. But the cavers themselves understand. Many experienced cavers have watched some of their favorite places turn from a mystical underground fairyland to a dark dirty troll's den in the space of a few years. Research literature documents the destruction of caves as their location becomes known to the public at large. For this reason, the location of the vast majority of caverns is a closely held secret. A pristine cave is a rare and precious resource that is too easily lost to vandals. As a consequence, most casual cave visitors will never know the experience of a newly discovered cave. But there is a way that they can come close.
Helictites and stalactites in Black Chasm Cave
There are around a thousand known caves in the Sierra Nevada, and six are open for tours: Crystal (in Sequoia National Park), Boyden (just outside Kings Canyon National Park), Moaning (near Columbia), California (outside San Andreas), Mercer (near Murphys), and Black Chasm. Each of them have their charms and educational value, but Black Chasm stands out. It is one of the few that has the feel of an undefiled cave, at least once you've crossed the "chasm".
The "Dragon", mascot of Black Chasm. That's not the normal color...the guide was using a laser pointer on it.
The miners who discovered most of the Sierra caves explored them with smoky torches or candles, and they as well as those who followed over the years had no compunctions about touching and breaking off the speleothems (cave decorations) found in the caves. Owners even encouraged visitors to take a souvenir, thinking that the stalactites would grow back within a few years. These caves ended up with dirty walls and ceilings, and the only stalactites left were those that were out of reach of visitors. This also happened at Black Chasm.
But a short distance into the steep cave entrance the rocks drop off into the inky darkness of the chasm itself. It's around 90 feet deep with sheer walls and a series of small lakes or ponds at the bottom. Getting to the rooms beyond required technical climbing skills that weren't practical until the 1960s and 1970s. Those who were then able to explore deeper into the cave were careful spelunkers, not vandals, and the rooms they found were spectacular.
When the owners decided to develop the cave, they constructed a series of stairs and bridges that provided access to the back rooms of the cave, but the stairwells also prevent tourists from getting too close to the pristine decorations. And what wonderful decorations they are! The first thing I always notice is the pearly white color of the dripstone and flowstone features. They don't have any soot or dirt on them at all. The next thing that comes to my attention is the total lack of broken features. They quite literally look the way they did when they were first discovered except for the lighting. Because the flowstone and other features are translucent, the owners were able to place the lighting behind the features so the light could glow through. The photographic results sans flash are wonderful. Flash pictures always seem to make the speleothems look flat and featureless.
The crowning feature of Black Chasm Cave is the number and variety of helictites. They can be thought of as stalactites on drugs. They don't believe in gravity and have instead grown in all kinds of directions, almost as if someone took handfuls of spaghetti noodles and tossed them onto the wall. They are rare in caves, especially those open to tourists, in part because of their incredibly fragile nature. A single touch would be more than enough to snap them off. But it hasn't happened at Black Chasm. The sheer number on some walls (thousands of them) have resulted in the cave being declared a National Natural Landmark, a federal program that encourages owners of outstanding natural features to protect their resource (of course it doesn't hurt their public relations).
The owners of Black Chasm Cave have done a great job of protecting their resource, and their tours are done well. In addition, they encourage educational groups by offering steep discounts, so I have no problem recommending them to my fellow educators. Information about visitation and tours can be found on their website at https://caverntours.com/black-chasm-cavern-national-natural-landmark/. They also have an excellent nature trail on the property (that will be in the next post), plus a curio shop with some surprisingly sophisticated speleology texts for sale, along with the usual geodes and t-shirts.

Don't ever stop exploring!