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!

The Sequoia Underground: An Exploration of Crystal Cave

It's true that Crystal Cave in Sequoia National Park can hardly be described as a wild cave. Since its discovery in 1918 and its development as a park attraction in 1940, the cave has been visited by more than a million people. Dynamite was used by workers to widen passageways, and besides the lighting and pathways, there was a generator, and underground bathrooms. And yet there is still something wild about the cavern. Because it was discovered by park personnel and protected from vandalism from the beginning, the cave presents some wonderful examples of speleothems (cave decorations). The cave has a total of 2.42 miles of passageways (the third largest in California), but only a fraction ever receives visitors. The rest remains an underground wilderness.

The cave is an integral part of our field studies course on the geology of Sequoia and Kings Canyon National Parks. We paid a visit this last weekend and made the cave our first stop. Our tour began with an orientation on White-nose Syndrome (a fungus that kills bats), and sterilized our shoes. We then started down the half mile trail to the cave entrance.

The trail itself is a pleasure, and a good introduction to the local geology. The rocks are part of the Kings Terrane, a group of metamorphic rocks that formed in a shallow marine setting in Triassic and Jurassic time (around 200-150 million years ago) with some parts possibly older. The rocks formed in the Pacific Ocean and were accreted to the western edge of the North American continent as the mass of continental crust entered into the vast subduction zone that was consuming the ocean crust. The collision and subsequent invasion of the rock by molten granite caused the silt, sand and lime mud to become schist, quartzite and marble. It is in the marble that we find the caverns forming.

The trail provides a nice view of the marble cliffs. Permanent springs cause Cascade Creek to flow year round, providing a cool stretch of trail on a hot day and some beautiful small waterfalls.

Soon we reached the entrance to the cave and met our guide. The cave is administered by the Sequoia Natural History Association and is generally open for tours from the early spring to late fall.

A cool breeze was blowing out of the cave. The temperature is controlled by the average year-round climate, so the cave is relatively cooler in summer, and warmer in winter. Although the darkness of the cave provides little in the way of food, a number of animals do live in the cave, including a number of species of bat, and small arthropods like spiders, isopods and pseudoscorpions.

Entry into the cave is controlled by the famous spider-web gateway. I remember vividly seeing that gate when I visited the park for the first time as a child in the 1960s, and I remember the gate (and the underground bathrooms) the best.

Given the number of visitors, it's amazing that any cave decorations are left. It's to the credit of the park service and history association workers that so little damage has been done, although plenty of bad things have happened (the park service actually allowed self-guided tours for a brief time with disastrous results). The improvements to the pathway have actually meant that some of the stalactites and stalagmites have begun healing from previous damage, as evidenced by the pure white calcite on some surfaces. Dust from tramping feet and smoke from torches left many features a dingy yellow or brown color.

We passed some beautiful stalagmites on the floor of the cave, and then moved into the Junction Room, which was filled with the sound of babbling little brook. The cave is still very active, as it diverts a nearby creek underground. There are several levels to the cave, developed as the local canyons outside have gotten deeper, causing the rivers inside the cave to erode downward. There are numerous benches and terraces attesting to the former presence of higher level streams.

We moved through the Curtain Room, where a profusion of cave curtains and draperies hang from the walls and ceiling of the cave. They are out of reach of vandals and are thus largely unbroken.

The Dome Room contains one of the cavern's most famous features, the Fairy Pools. The rimstone pools and soda straws are actively forming (and recovering slowly from vandalism).

A zoom onto the soda straws (below) shows the water droplets on the ends. In these conditions, soda straws can grow at maybe an inch per century.

The unbroken draperies show an intricate structure.

The Marble Room is the largest in the cave, extending for more than 100 feet, with the ceiling 30 feet above. It is an amazing sight. It's also where they turn out the lights and let explorers get a feel for total darkness. Some people really don't like the sensation.

There are nearly 300 known caverns in Sequoia and Kings Canyon National Parks (Boyden Cave, another developed cave, is just outside the park boundary). The caverns include Lilburn Cave, which at 28 miles of passageways is in the top twenty of the largest caves in the nation. Most of the wild caves are remote, and their locations are kept secret for obvious reasons. Clough Cave was known a century ago as a beautiful cave festooned with thousands of stalactites. When the cave was publicized, the speleothems started to disappear, and today Clough Cave is pretty much a featureless hole in the ground. Several vandals were caught by park rangers in 1997 stealing some of the last artifacts in the cave. What a crying shame.

In the meantime, if you ever visit Sequoia or Kings Canyon, be sure to give the cavern a look. You won't regret it!

Where are the Ten Most Incredible Places You've Ever Stood? My Number 4: What is it like to be the first person ever to see a cavern?

Can you imagine flashing a light in a dark corner of a cavern, knowing that you are the first human being ever to lay eyes on the formations? I haven't had that privilege in my life, but I have found two or three places where I can imagine what the experience was like. Most of the caverns that are accessible to amateur spelunkers like myself have been long known and rather completely explored. Unfortunately, most of them have been severely vandalized, and the early use of torches for light left soot deposits on the formations. It is a rare treasure to see a cave where damage has not yet happened. Such caves in my experience include California Caverns near San Andreas, California,  Black Chasm Cavern near Jackson, California, and the subject of today's post, Kartchner Caverns near Benson, Arizona.

Many of the speleothems are still active; there are water droplets on many of the soda straws

The "Ten Most Incredible Places I've Ever Stood" series has been a series of hard choices. This one made the list because of the shock and the awe, the way the cavern made my jaw drop as I stepped in. It is an experience unlike any other that I've had while underground. There is a difference between even a well-protected cave, and one in which whole areas have never been touched by a human being. The floor of one of the large rooms was covered with mud, and it was clear from the trackway above that only one trail through it was ever made, in order to put in a light source. The rest of the room remains as it was discovered.

How incredible is it that some of the soda straws that fell are still standing in the mud?

The discovery and visitation of any cave causes irreversible changes. Kartchner Caverns were discovered on private lands in 1974 and the people who found them were concerned about preserving the original cave environment. The cave was at nearly 100% humidity, and opening it to the desert environment would have dried it out. Such changes in humidity can adversely affect life in the cave and stunt the growth and development of speleothems (cave decorations like stalactites and stalagmites). And yet the caves were spectacular. Was there some way of preserving the caves while making them accessible to the public?

The discoverers hit on an audacious solution. Through a series of delicate and secret negotiations, the owners of the land agreed to sell the lands containing the cave to the state of Arizona to be developed as a show cave, but to be developed in such a way as to preserve both the features and the climate inside the cave (many of the legislators didn't know what or where the park was when they voted for it). They preserved the humidity of the cave using a series of unique airlocks. Pathways were constructed with a minimum of disruptions to the original configuration of the cave. It took 25 years from the time of discovery to the opening of the park to the public in 1999.

There was one catch. Nothing goes into the cave with the visitors. No food, no water, no backpacks...and no cameras. As you might expect, I live for photography and this for me was a hard restriction. In 2005, though, I got the opportunity of a lifetime: as part of a fund-raiser for the park's foundation, they had a photography day, and the National Association of Geoscience Teachers made arrangements for us to take part. I was going to be given access to the cavern to photograph to my heart's content. To be sure, I had to sign a waiver of commercial rights, and the images that you see in this post today are protected and cannot be sold or used in any way.

Perhaps the most incredible stalagmite/column I've ever seen

What a wonder it was to step into a cave that appeared the same as it was on the day of discovery! The airlock closed behind me and although the temperature was only 78 degrees, it felt much hotter because of the intense humidity. The passageways were dimly lit and it took some time to develop my night vision. But moment by moment the cavern came into focus. It was simply stunning.

I wandered from passage to passage lost in the moment. It was nice not having a guide (staff were stationed throughout the cave to answer questions and keep an eye on things), but it was also nice to be exploring a pristine cave knowing I wasn't doing major damage just by being there. Exploring a newly discovered cave means leaving muddy footprints and accidentally destroying delicate formations underfoot, or leaving trails in the mud. I remember thinking that the experience was something like being in a museum, but I thought that in a good way: the resource was being protected, and yet hundreds of thousands of people could see and enjoy it. 

Some marvelous "helictites", otherwise known as stalactites on LSD.

Although I can't be mistaken for a professional photographer, I learned long ago that photography in a cave is always tricky. There is no "natural" look to a cave except total darkness, but a camera flash steals perspective and washes out delicate differences in color and shading. I used the ambient lighting to maintain some depth to the photos. That meant standing very still for longer than usual exposure times (tripods weren't allowed at the time). 

Flowstone refers to speleothems that result from water seeping out of cracks in the walls of a cavern. Over time gigantic mounds build up that resemble ice cream sundaes. Kartchner is full of spectacular examples.

I'm not sure what to make of the features below. There are some nice soda straws, which are so delicate that they are the first to be broken off in unprotected caves. The spiky things are the beginnings of helictites, which tend to ignore gravity, growing instead under the influence of water pressure from the interior of the "confused" stalagmites.

Below, one can see a spectacular column in the foreground, and some marvelous draperies in the upper left background. None of the features were broken off, and none were vandalized. I can barely describe what it is like being in such a place. Every minute in the cave was precious. I know there is an argument about worrying over technology in situations like this, and that one needs to live in the moment, reveling in the experience of being, but I actually find caves disorienting. Despite all my orienteering skills on the Earth's surface (and people tell me they are formidable) I get lost in caves. I can't remember one room or one decoration from another. Photographs keep me centered, and keep the memories of the moment alive. And I can share them!

I passed a stunning wall of draperies. Time was beginning to run short and I would be needing to leave this fantastical world for the surface before long. I was sweating, dehydrated, hungry and tired. It wasn't difficult getting around, but the humidity gets to you eventually, draining your energy. I started to head for the exit chamber and the airlock to the outer world.

There was one last close-up of a moist, almost glowing surface of some flowstone, and then I was out the door to the world of light and fresh air. The contrast was shocking. Caverns are incredible places, but they aren't really a human environment. I can understand how the first explorations of caverns could awaken our ancestors to the ideas of shadow-worlds with their demons and nightmares. Hell was presented as an underworld of fiery pits and eternal torment. But in a different context, caverns have been a place where dreams come alive. I think of the spiritual awakening of an initiate in a deep cave thousands of years ago encountering the drawn images of animals and people on a cavern wall seeming to run and play in the flickering light of a burning torch. Wandering through a pristine cave in the present day brings us face to face with a fascinating world that is not completely apart from us. The deep hidden parts of caves may not be a human environment, but much of our early spiritual and cultural development derived from living and exploring the outer edges of the underground environment. Caves are places where magic seems possible.

The Sierra Nevada Underground: Into the Black Chasm

California is full of delightful geological surprises. Mention "caverns" and most Americans will think of places like Mammoth Cave, Kentucky, or Carlsbad Caverns in New Mexico. Not too many people will think of California, but California does have an unexpected number of world-class cavern systems.

The state has such a complex geologic history involving granite intrusions, volcanic eruptions and earthquakes that it is easy to forget that for vast stretches of geologic time, California was stunningly boring passive continental margin. In Paleozoic time, the region was a shallow sea, slowly collecting mud and lime deposits in a tropical environment. In some cases, the tropical islands and shorelines were elsewhere, but the rocks were transported to California on the giant conveyor belt of the Pacific and Farallon tectonic plates. As the Farallon plate was subducted beneath the continental margin, the limestone sequences were scraped off and added to the metamorphic sequences of the western Cordillera.

The limestone was baked and transformed into marble, and a great deal of marble was preserved in a tract of crust (or terrane) in the western Sierra Nevada Metamorphic Belt called the Calaveras Complex. The Calaveras hosts many of the caverns found in the state; there are hundreds of them. Unless I lost count somewhere along the line, six caverns in the Sierra Nevada have been developed for public tours: Crystal Cave in Sequoia National Park, Boyden Cave in Kings Canyon, and four caves in the Mother Lode: Moaning Cave, Mercer Cavern, California Caverns, and today's destination, Black Chasm Cavern.

I was at Black Chasm yesterday with twenty of my students, on a field studies trip through a portion of the Mother Lode. The cave is privately owned, but it has been granted National Landmark Status, a designation that recognizes the geologic or historic importance of the cave, and encourages the preservation of the feature. The owners have done an good job at Black Chasm. It is one of the best places I know of that gives the casual visitor the experience of seeing a cave that is close to pristine condition, much as when it was first discovered.

The problem is that many Sierra caves were discovered by miners in the 1850s, and they became well-known and well-visited. It was not at all unusual for the cave owners to encourage their visitors to take a stalactite as a memento of their visit, and the caves were stripped of their decorations (speleothems would be the proper term for the stalactites and other features of caves). The early explorers often used torches for light, and the soot left its mark on the remaining speleothems.

Black Chasm was discovered early on, but it was the cave's namesake that protected it from the worst damage. The entrance into the cave is very steep, and after clambering down the steep slope, probably hanging onto a rope, the early visitors passed through one interesting room, but then found themselves perched on the brink of an eighty foot cliff that ended in the darkness below. Without technical equipment there was no going forward or going down. The interior passages of the cave were protected from vandals by inaccessibility.

When the owners of Black Chasm decided to open the cave for tourism, they constructed a walkway that clings to the wall of the Black Chasm and passes into the rooms beyond. The contrast between the first room of the cave and the last room is striking. Many of the stalactites and other speleothems are broken off, and the remaining ones have a patina of orange-red mud that comes from seepage of iron oxides from soils above, but also from soot and dirt from the early visitors. The room is still pretty, but not exceptional to anyone who has visited other caverns.

Then you pass through the namesake chasm. The walls on both sides are vertical, and in the inky darkness below there is a deep lake. The cave is host to a unique species of amphipod, which I hope is immune to the effects of fallen eyeglasses, cameras and other paraphernalia dropped by visitors. The owners clean up what they can, but cave diving is a seriously dangerous business, and I don't think they do it casually for cleaning things up.They warn you to hold onto your valuables...

And then you start to see what an undamaged and pristine cave is really like...the parallel fins are referred to as cave bacon.

The natural color of most speleothems is a pearly shade of white. It's truly hard to resist touching these decorations, especially since they are so close to the walkway. I trust you won't do it if you visit. It is far too easy to cause damage or mar the appearance. It is such a privilege to be able to see things like this without a plastic screen blocking the way...

The cavern has some nice examples of soda straws (above), which are very thin stalactites that are among the first speleothems to disappear in unprotected caverns. One touch would be enough to break them off. I've seen some in Kartchner Cavern in Arizona that broke off without being even touched. The just broke off, maybe from something as weak as wind currents or the shaking of a distant earthquake (the effects of quakes are muted in caves, as they are much less affected by surface wave shaking).

The draperies in the far room of the tour are nothing short of fantastic. The lighting is nicely placed to allow for back-lighting. Flash photography from handheld cameras almost never works in caverns. The flash washes out any contrasts in color, and without shadows, the features lack depth. I get a lot of non-flash pictures that I have to delete because I shake too much, but the few I get with the back-lighting are far more satisfying.

The final room of the tour is exceptional because of one particular kind of speleothem: helictites. Helictites can be characterized as stalactites that refuse to recognize the law of gravity, or by some descriptions, stalactites on acid. They have grown in random directions, perhaps because the water that formed them was driven as much by capillary action as it was by gravity.

From a distance, the wall looks fuzzy with white "stuff"...

Up closer, the fuzz resolves into thousands of individual helictites.

I can almost imagine them wiggling about and forming into a tourist-eating cave monster...

The complexity of the helictites is just stunning. I never get tired of trying to get another shot. Shawndee, the manager at the cave, probably thinks I'm ignoring her while she is talking to my students, but I do listen. I'm just multitasking, trying to get the perfect shot!

I always see something new whenever I go into Black Chasm. This time it was the dogtooth spar crystals in an obscure cavity along the walkway. Dogtooth spar is a crystal form of calcite, which along with aragonite is the mineral that makes up most of the speleothems in the cave.

Black Chasm Cave, as noted before, is a privately owned business. They are there to make a profit, but they have done a good job of protecting their cave, and I recommend a visit. They offer discounts for educational groups (they can accommodate up to 22 people at a time, so large classes would need to split into two tours). More information about the cave can be found here. Tell them Geotripper sent you!