Lehman Caves in Great Basin NP

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One of the big attractions at the Great Basin National Park is the Lehman Caves tour. On Wednesday, March 27, 2019, we met Ranger Brenna for our 1:00 p.m. tour. Before beginning our descent into the underworld, Brenna gave us a little history of the area.

The caves were discovered by Absalom Lehman back in 1885. He was homesteading on government land. To make a little extra money, Mr. Lehman would charge visitors $1.00 to show them the entrance to the cave and give them a candle to light their way.  The cave system is extensive, as this NPS map shows, and the ensuing years have in part been the history of making more of the caves accessible to more of the public.

In 1922, the area became a National Monument. In 1933, control of all national monuments, including Lehman Caves, was turned over to the National Park Service. Even though the area was run by the NPS, this area didn't become a National Park until 1986.

As we began our tour, we were warned that Lehman Caves are wet! It is the water leaking down from the surface through cracks in the limestone that allow the stalactites and stalagmites to grow. Several walkways had standing water. The humidity level in the caves is 95%. Those light drips landing on your head are known as cave kisses and they bring good luck. Just be careful looking up!

Portions of a movie originally titled The Wizard of Mars, a science fiction horror take on the popular Wizard of Oz, were filmed inside the cave in 1965. The flick was later renamed Horrors of the Red Planet. The formations we encountered definitely looked alien.

We encountered all sorts of formations such as flowstones, popcorn, rimstone, draperies, stalactites, stalagmites, helictites, shields, soda straws and columns.

The acidic water from the surface carries down various minerals. In certain locations in the caves, the iron from the surface adds a light red shade to the cave surfaces.

The low light in the cave made for interesting photos.

Ranger Brenna had a blacklight (ultraviolet) flashlight which shone infrared light onto the bacteria growing in the cave. Some of the bacteria was phosphorescent. It absorbed the infrared light and continued to glow after the flashlight was turned off.

Before the Lehman Caves were incorporated in a National Park, tourists were allowed to take home souvenirs. Many of the features closest to the trail were broken.  This resulted in many stalactites and stalagmites terminating suddenly in a flat end, rather than a pointed end.  Here is a photo of stalactites hanging from a low ceiling in the cave; some of these have been broken:

After seven years of drought, with the copious precipitation this last winter, many of the cave pools are now full again.

When a stalactite meets a stalagmite it becomes a column.

Once a column is formed, it can continue to grow and expand, looking like giant drippy sand castles.

Several times along our tour, we turned out our lights to experience complete darkness. Unfortunately, the pictures from that part of the tour didn't turn out. However, when folks turned their flashlights back on, it made for some cool effects.

Pictured below are rimstone dams on the floor of the cave. Each dam, or rimstone, grows into a generally circular shape and holds a small pool of water inside it. Water flowing over the top of the rimstone dam deposits more calcite, increasing the height of the dam.

The only unexplored area of the cave was above our heads. The tunnel leads toward the surface, but no one knows for sure how far it goes. The formations along the sides are too fragile to allow exploration of it. The water dripping down the vertical tunnel into the main chamber is full of organic material giving the formations below the opening a greenish/brownish look.

The stalactite on the right in the photo below was broken off, exposing its crystal core. While the core shows rings, it cannot be dated like tree rings. Stalactites can only grow if there is enough water to bring down more minerals. Years could go by with no new growth rings.

There was only one room we could not enter for safety reasons. The Talus Room is littered with large pieces of the falling ceiling. As an area of the cave dries, the formations can crack and fall.

The formations in Lehman Caves are very dramatic. Some of the most unusual types of formations are the parachutes.

Over the years, many different materials were used to create trails through the caves. In one of the more recent sections, the cave floor was left untreated and is forming rimstone pools. Under the blacklight, the rimstone pools are highlighted and shown to be filled with fluorescent bacteria.

All too soon, we were lined up waiting to leave the cave. We turned our lights out one last time to say goodbye to the dark.