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!

Spring is Coming, and Flowers are Awakening in the Sierra Nevada Mother Lode

It's still a bit early to see the awesomeness to come, but the spring wildflowers are beginning to make a splash of color in the Sierra Mother Lode. With the record and near record amounts of rain in Northern California, the slopes are primed to produce a wildflower show to compete with the "super-blooms" taking place in the California deserts this year. We were exploring a portion of the southern Mother Lode in the vicinity of Mariposa and Coulterville yesterday, and I took my attention off the rocks for a few moments to catch some pictures of the early-blooming flowers. Above is a Fiddleneck (Amsinckia species), often one of the first of the wildflowers to bloom in this region. It can be poisonous to livestock, and yet was used as a food and medicine source by Native Americans.

Near the Pinetree-Josephine Mine we saw a number of Brodiaea, or Blue Dicks (Dichelostemma capitatum). These beautiful flowers grow from bulbs that were also an important source of food to the Native Americans of this region.

I don't know as many wildflower species as I should, as much as I appreciate their beauty. In a few places there were carpets of small yellow flowers (Goldfields, in the Lasthenia genus, thanks to Siera Nystrom in the comments).

Seeing some of the flowers growing in the usually poisonous serpentine soils reminded me that it is time to head up to the Red Hills soon, a Mother Lode locality known for a large number of endemic species.

As per Jane Strong in the comments, Orobanche fasciculata, clustered broomrape. Thanks for the identification!

And finally, the ever-present and always beautiful Indian Paintbrush (Castilleja species). There are some 200 species of this flower.

This is only the very beginning of what promises to be a wonderful year for wildflowers. I hope to be bringing many more such scenes to your attention in coming weeks!

What To Do on a Rainy Day? Explore the Mother Lode Underground!

So what does one do when an atmospheric river storm is barreling towards your region, with an expected 10"-20" of rain in some places? If you are among the intrepid members of the Geology Club at our school, you go caving! It's not that they planned on doing a field trip during one of the heaviest storms of the year, but this was scheduled two months ago. They looked at the weather radar and decided to go anyway. In the end we caught a bit of breathing space between two major storm systems. It was mostly drizzling and misting on us as we hiked the mile or so down the hill to the cave entrances.

California is not exactly known for her cavern systems, but the state does in fact have around a thousand known caves, and some are world class; one has nearly thirty miles of passageways. Seven or eight of them are operated as tourist attractions (Black Chasm, California, Mercer, Moaning, Boyden, Crystal, and Shasta are the ones that come to mind). Many are on public land and plenty more are on private land (how cool would it be to have your own cave?) but their locations are not widely publicized, because a well-known unprotected cave is quickly dismantled by vandals, and the damage to caverns is permanent. You can't grow stalactites in a human lifetime.

We explore a couple of wild caves in the hills around Columbia. They occur in pods of marble that originated as carbonate reefs and shelf deposits in the Pacific Ocean in late Paleozoic time which were accreted to the edge of the North American plate by the process of subduction. The suite of exotic rocks are called the Calaveras Complex.

We had to pay obeisance to the mystic black cows that guard the cave entrances (well maybe anyway; they certainly like to hang out on the grass-covered plateau where the caves are located).

There were two caves that we explored today. The first was a smaller "practice" cave that provided a few crawling and climbing opportunities and some nice speleothems in a small gallery. The cave had three entrances and several small rooms that angled away from the central area.

Caves are explored these days with flashlights and headlamps, but it hasn't always been that way. The miners used candles, and the native Americans would have used torches. The caverns have a completely different aspect by candlelight. There is literally a primal mystery hidden in the shadows. I developed a greater appreciation for the cave paintings done by our distant ancestors in Europe. Can you imagine being led into the depths, and then have the torchlight suddenly play on paintings of animals and people in the darkest parts of the cavern?

The other cave is a bit more of a challenge. One must first climb down some slippery boulders into the collapsed sinkhole, and then push up through a very narrow passage that is a pretty tight  squeeze...especially for late middle-aged fat professors. But what a payoff! The 150 foot-long main room is festooned with hundreds of unbroken stalactites and columns. The ceiling was high enough to prevent vandals from reaching and breaking them off. And frankly, most vandals are lazy bastards; it's a tough hike and fairly difficult to find unless you know exactly where to look (on my fourth trip to the caves many years ago I got lost in the fog and wandered aimlessly for an hour or so).

If you wonder about cave life, there are certainly creatures living in the darkness. There are usually two or three bats hanging on the highest ceiling (although there is no light, I suspect there is a vertical entrance to the cave somewhere, because I can't imagine bats negotiating the narrow hole we climb through, but maybe they can).

On this particular day we saw half a dozen 5-inch-long millipedes. I'm told they are mainly scavengers and don't bite, but I didn't experiment with the possibility today.

I didn't see any of them today, but a couple of years back we saw a beautiful orange newt deep in the cave (I think it is a Sierra Newt, but as in all things biological I am open to correction).

Wow, Thanksgiving is over and Christmas is coming, but I'm already out of shape and overweight. The climb up out of the cave and the long mud slog back to our vehicle was tougher than it should have been. But what a nice day it turned out to be...

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!

The Sierra Underground: Wild Caves, a precious and easily damaged environment

I spent the day in the Sierra Nevada foothills checking out a couple of wild caves with a few students. The Sierra is justly famous for spectacular alpine scenery; the underground scenery is a tad less well-known. Just the same, the region has some spectacular caves, including a half dozen that are open for commercial tourism. Others are hidden away in the brushy hillsides and are a great deal harder to reach and explore, and that is the way it should be.

Wild caves are a precious resource, and are easily damaged. The damage is permanent. Accessible caves have been completely stripped of their speleothems (cave decorations like stalactites and stalagmites) and filled with garbage and graffiti.

I was in the inner sanctum of a particularly beautiful cavern, and thankfully many of the stalactites remained unbroken. I've been in this cave several times, so instead of exploring the far corners, I sat and tried different approaches to capturing images of the thickest accumulation of stalactites near the entrance. It's a tricky process, especially for a novice like myself. Flash pictures don't cut it because there are few shadows to provide depth. I caught three images I was happy with by opening the shutter for 20 seconds and having my fellow explorers move their light sources over the target speleothems.

The exploring of wild caves is not for everyone. You have to get used to crawling through tight spaces, and getting covered in mud. It can be exhausting work. Caves can be unsafe, with unstable rocks, steep dropoffs and bad air. Hurt yourself in a cave and it is difficult to get you to medical help. Go in without sufficient light sources, a knowledgeable guide, and improper equipment, and you could end up lost in the dark. Caves do not generally offer landmarks for finding your way out.

Our cave today required squeezing upwards through narrow opening with a projecting rock that meant one had to push up and turn sideways at the same time.

This was after negotiating the collapsed rocks that provided entrance to the bottom of the sinkhole that contained the cave entrance...

Yeah, Geotripper was tired afterwards...then there was the mile long hike up the mountain to the vehicles. It was a good day.