Black Chasm Cavern

EFFORT Minimal
LOCATION15701 Pioneer-Volcano Road, Volcano, CA
TRAILHEAD COORDINATES 38.26.059N, 120.37.556W

Description: Calaveras County’s newest nugget is an amazingly beautiful and fragile living limestone and marble cave that was opened to the public in September, 2000. It was something of a secret prior to development, declared a National Natural Landmark in 1976, but available only to a few individuals and groups for study. Its landmark status was granted primarily due to its substantial colony of rare helictite crystals. These are unusual looping and twisting white fingers of calcite that are hollow like soda straws, but growing at every possible angle.

As recently as February 2001, a spectacular new chamber was discovered, and there may be more to come. Exploration of the cave continues, although some passages are so choked with delicate crystals that spelunkers avoid passage in order not to damage them. So far, the public tour is limited to a few rooms, estimated to be about one-sixth of the tourable cave, but the trail system will continue to expand. Great care is being taken to preserve the cave’s natural state, including the construction of expensive elevated trails designed to keep visitors off of the floor. The stairs, railings, and viewing platforms are made from recycled soda bottles instead of traditional materials such as wood to avoid leaching chemicals into the environment.

Fortunately for us, visitors of earlier generations were able to enter only the first few feet of the cave, so damage characteristic of that time is limited to the area just inside the entrance. Otherwise, the preservation is exemplary. The cave is managed by Sierra Nevada Recreation Corporation, which also manages other area caves open to the public. When we visited, in the summer of 2001, tickets were sold out of a trailer, and signs of construction were everywhere, both above ground and in the cave. Now there is a visitor center and more civilized facilities.

The Landmark Tour includes the Colossal Room, 100 feet across and 150 feet deep, and the Landmark Room, famous for its massive arrays of helictites. Be prepared for stairs, lots of them, as the tour is essentially a trip downstairs and then back up. It begins by passing through a narrow opening and descending down the first flight of stairs to a platform suspended between the walls of the fissure. You can see well-lit stalactites, stalagmites, helictite, draperies, flowstone, columns, and other familiar cave formations. Looking down, you will see a small portion of the deep turquoise lake seventy feet below, colored by naturally-occurring calcium bicarbonate. A future Rapunzel Tour is planned to take visitors down to the lakes for a close-up view, but for now, this is all you will see of the mysterious water below.

This is the best spot on the tour to recognize that the cave was formed along a joint, and the basic shape of the area is a narrow chasm that you will traverse almost vertically from top to bottom. Because of the sheer vertical drop almost immediately within the entrance, this cave would not have been a viable human habitat. No archeological artifacts have been found here.

The walkway continues through the Landmark Portal and down into the Landmark Room, which contains impressive displays of spectacular helictites in the walls and ceiling. Helictites are formed under unusual conditions, which include water under pressure and the presence of certain trace minerals. As water droplets emerge through the rock to an exposed, vertical wall, they cling to it by surface tension. Rings of calcite are formed where the droplets make contact, and build up into hollow tubes. These tubes begin in a more or less horizontal manner and then twist and turn in bizarre shapes as random crystals grow. Since helictites must battle gravity, they do not usually grow much larger than a few inches, but at Black Chasm Cavern there are many long helictites, including one near the entrance to the cave that measures twelve inches long.

The Landmark Room also contains one of the most beautiful flowstone formations you will come across. Your guide will point out some of the small passageways that may eventually host cave-cams. You can easily see that these crystal-choked passages will not allow for visitors, walkways, ladders, etc., without significant destruction.

This is the end of the tour, from which you retrace your steps up to the entrance, squeezing past the next tour group along the way. Not yet on the tour is the colossal Hall of Arches, a complex maze of marble arches that span wall to wall over and under each other. Perhaps we will return in a couple of years to see some more of this amazing underground fantasy as it is further revealed to the public.

Driving Directions: From Stockton, take Highway 88 east to Pinegrove. Turn left at Volcano-Pinegrove Road and continue three miles to the bottom of a big hill, make a steep right turn onto Pioneer-Volcano Road and continue about 1500 feet. Turn right at the Black Chasm National Natural Landmark entrance. You will come to a parking area alongside the road. This is overflow parking. Continue past it to the main parking area and visitor center. The cave is open daily for public tours. Expect a reasonable wait of about an hour for your tour time, the perfect opportunity to sit down to that picnic lunch. There is a fee for the tour.

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