Showing posts with label speleothem. Show all posts
Showing posts with label speleothem. Show all posts

Monday, November 16, 2015

The Karst Topography...of California? A Look at California Caverns


We took a field studies trip a few weeks ago, and it turned into a mini-series on the karst terrain of California, a landscape that forms over limestone and marble. The development of caverns leads to distinctive features on the surface above, including sinkholes and disappearing streams. I've covered the sights we saw on that trip, but there are plenty of other caverns across the state, more than a thousand of them. I've only explored a relative handful, but the ones I've seen are spectacular. I'm going to explore a few more of them in coming posts.
Today's post is about some caverns in the Mother Lode of the Sierra Nevada named after the state. California Caverns have been known since the Gold Rush days, and etchings in the cave dating to the 1800s attest to the long history of human exploration. To no one's surprise, the well-traveled parts of the cave have been used and abused. It was standard practice in the old days to break off stalactites as souvenirs, and to use a cavern wall as a register.

This fact is what makes California Caverns a special treat. In the Gold Rush days, only about 300 feet of passageways were known, and the worst damage occurred in those passages. They are rather barren and unremarkable.
The deeper passageways are somewhat less damaged, and the cave becomes more interesting. Some of the higher ceilings escaped vandalism and retain some marvelous examples of cave bacon.
Our guide takes us into the deeper passages to the Bridal Chamber. There is an immense mountain of flowstone in the back that is just stunning. It is noticeably cleaner and white than speleothems in the previous passageways. In older days, this was the end of the cave. A debris-filled passageway behind the Bridal Chamber went unnoticed for many years. Several decades ago, spelunkers started moving the debris, and squeezed through an extremely narrow hole (which would have caused me to become unhinged, given my tendency towards claustrophobia in certain situations).
The explorers emerged into a stunning chamber, now called the Jungle Room. No human had ever set foot here before. I can barely imagine what that was like. Luckily, they kept the room a secret for years, safe from vandalism, before preparing the cave for public tours. Now, anyone can see what a pristine cave looks like. It's true that pristine caves don't have carefully placed lighting, but one can think of the situation as being like a museum exhibit: the art is carefully managed, and lighting is used for highlighting the best perspective.
The room is filled with incredibly delicate stalactites and soda straws, the kinds of speleothems that are the first to be broken off by vandals and souvenir hunters. There are thousands of them, each one a treasure. They are pearly white, having never been grimed up by torches and sooty lanterns.

Dark corners hint at additional passageways, and indeed California Caverns are now known to be one of the longest caves in California, at 1.4 miles (the longest in the state is Lilburn Cave in Kings Canyon National Park at 21 miles, 28th longest in the United States).
Every corner of the Jungle Room is a revelation...I could almost feel the joy that John Muir felt when he visited the caves before they had been so badly defaced:

Here we lingered and reveled, rejoicing to find so much music in stony silence, so much splendor in darkness, so many mansions in the depths of the mountains, buildings ever in process of construction, yet never finished, developing from perfection to perfection, profusion without overabundance; every particle visible or invisible in glorious motion, marching to the music of the spheres in a region regarded as the abode of eternal stillness and death.
The caven is still active. In wet years the lower passageways are filled with water and must be pumped to provide access. Seeing the water flowing across the surfaces of the cave decorations provides greater depth to their appearance.
California Caverns were in the center of the area that burned during the Butte Fire in September, and they lost power and water. Amazingly, the visitor center survived, but vegetation in the area was severely affected. The caves are open for visitation, however, and are being done temporarily as lantern tours. You can get updates concerning the caves by clicking here
California Caverns are another treasure of the state's karst topography. They are worth a visit if you are ever in the vicinity of San Andreas in the Mother Lode.

Thursday, November 12, 2015

The Karst Topography...of California? Into the Black Chasm

California is not really known for her expanses of karst topography, the landscapes that develop where limestone or marble lies underground. In my short mini-series about the karst of California, we've seen the gold-fields of Columbia State Historical Park, the grinding stones at Chaw'se State Park, and the Natural Bridges of Coyote Creek. Today we are going underground to see the reason for the sinkholes and disappearing streams: the caverns of California. Believe it or not, there are more than a thousand of them! There are about eight of them that have been developed for tours. We'll have a look at some them over the next few posts.
On our recent trip exploring the karst topography of the Sierra Nevada Mother Lode, we visited one of the most unique: Black Chasm Cavern, near the Gold Rush town of Volcano. Black Chasm was opened for tours around 1990, but it has been known since the Gold Rush days.
An early discovery by miners is usually the death-knell for a cave. The early explorers tended to be careless, and they thought nothing of breaking off cave decorations (speleothems). Such caves eventually became muddy holes in the ground, bereft of any beauty. But Black Chasm had something going for it, something that protected the cave: it was the Black Chasm itself.
Just inside the very step entry passage, there is a 100 foot deep fracture that halted any further exploration of the cave unless the spelunkers had technical climbing gear. Far down at the bottom of the chasm, there is a turquoise colored lake. When the cave was developed, the owners affixed a stairwell across the upper part of the chasm, providing access to the Landmark Room at the far end of the cave (the tour covers several hundred feet of the cave, which has a total of about 4,000 feet of passageways).
The Landmark Room is a true revelation for cave enthusiasts: it's almost completely untouched by vandals and sloppy cavers. The speleothems (cave decorations like stalactites, stalagmites, columns, draperies, and flowstone) have never been snapped off or otherwise damaged.
The stalactites and draperies are spectacular. The owners have done a good job of lighting the cave to highlight the most interesting decorations. I've toured the cave a dozen times or more, and I always find something else to photograph.
It's quite amazing to see draperies that have never been stained by the grime of torches and candle lanterns.
The speleothems could be easily snapped off, but it has not happened. It's a marvelous privilege to see untouched caves. But Black Chasm has achieved National Natural Landmark status for a different reason: the helictites. National natural landmarks are established by the federal government, but the land where these landmarks have been established are privately owned. The status represents an agreement to protect the landmark from damage or development. 
The helictites at Black Chasm are extraordinary. They can be thought of as stalactites on an acid trip, as they seemingly have completely disregarded gravity as they have grown. They may start growing in the style of stalactites, but water can be squeezed from the interior under hydrostatic pressure, and grow in random directions. They aren't immediately apparent on the conducted tour, because they actually keep the lights in that corner of the cave off (we look where we are directed, after all). One begins to notice the helictites here and there in dark corners, a few dozen on the cavern walls. I'm perhaps giving something away here, but I am surprised every time the lights come on.
Because that's what happens. The lights come up, and there is a wall covered by thousands upon thousands of helictites in a chaotic pattern that is simply stunning.
Helictites are among the most delicate of cave decorations, the first to be destroyed by vandals and careless cavers. But this cave was protected for a century by the Black Chasm, and the owners have been careful to preserve this incredible resource. They were never broken off, and as such, this wall of crazy stalactites is probably the most complex and spectacular group of helictites that can be seen in any show cave in the country, maybe in the world.
The cave is operated by the Sierra Nevada Recreation Corporation, and the cave is generally open all year for tours. They offer discounts for educational tours like the one we took two weeks ago. If you get a chance to tour the Mother Lode, Black Chasm is certainly worth a look. For more information, check out their website at http://caverntours.com/black-chasm-cavern-national-natural-landmark
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Saturday, October 31, 2009

Spooky Speleothems for a Saturday Scarefest

To be perfectly honest, I really detest the part of a cave tour when some teenaged guide who knows nothing of the geology goes on and on about how a particular cave decoration (speleothem) looks like a dragon or a elephant or whatever. On the other hand, the human mind has a great capacity for constructing forms and patterns out of totally random scenes. So, in honor of All Hallow's Eve I offer a picture I snapped in Lewis and Clark Caverns in Montana. I don't know about you, but I see at least one scary looking ghost and a cackling witch. What do y'all see?

Watch out for that candy coma tonight, and don't run over any trick or treaters!

Saturday, January 12, 2008

Picture of the Day

Black Chasm cavern is a commercial cave in the Sierra Nevada foothills east of the Gold Rush town of Jackson. The cavern has a number of unusually beautiful speleothems owing to the difficulty of access prior to development for tourism (in essence, vandals were blocked by a 90 foot dropoff near the cave entrance). The draperies seen here are spectacular, but other cave decorations are equally grand, especially a wall filled with helictites. More information about tours can be found at http://www.caverntours.com/BlackRt.htm.