California's Weirdest Rocks: The Tufa

California can boast many superlatives: it contains the lowest point in the continental USA, the tallest, largest and oldest trees in the world, and it is the most populous state in the country. But to my mind, it also deserves the title of Home of the Weirdest Rocks, and it owes that honor to one rock in particular: the tufa. Essentially, it's a common rock -- limestone -- that forms in uncommon circumstances -- underwater. When calcium-rich underwater springs mix with lakewater rich in carbonates, a chemical reaction occurs which forms these impressive and bizarre-looking towers of limestone. Because they can only grow underwater, of course, the only places you can find tufa formations are places where there used to be a lake. California, as I've written about recently, is chock-full of those places, and two of them had just the right mix of calcium-rich springs and carbon-rich lakewater to form what have become nationally-recognized landmarks of geologic weirdness: Mono Lake and the Trona Pinnacles.

Pictured above are the Pinnacles, set in the midst of the baking-hot Searles Dry Lake Bed, a half-hour from Death Valley and the location for movies and television series like Battlestar Galactica, Star Trek V, Lost in Space and Planet of the Apes. It was also -- according to conspiracy theorists -- the location where NASA "staged" the moon missions. Below are the tufa at Mono Lake, exposed thanks to large amounts of water diverted to feed hungry lawns in a city four hours to the south (hint: they make movies there).

From a distance, Mono Lake's tufa are barely visible:

They only poke up from certain heavily-trafficked sections of shoreline. A number of Mono's tufa formations are now hundreds of feet from the shore, a testament to just how much the lake's water level has fallen.

The LA water department has committed to filling the lake back up to 1940s levels, however, and though that's by all means a good thing, it also means that there will be fewer tufa to check out in years to come. So visit while the visitin's good!

As fascinating as Mono Lake's tufa are, the formations at the Trona Pinnacles are considerably more dramatic.

Here's a CGI shot from Tim Burton's 2001 remake of Planet of the Apes, with a computer-generated crashed spaceship set admist real-life tufa formations:

Not far away, a narrow gauge railroad hauls borax and other minerals from dry lake beds to nearby processing plants.

Up close, it really could be the surface of the moon. On the 100-degree summer day that I visited (a cool one by Trona's standard), there was no one else around for miles -- true solitude in an alien (or at least alien-esque) landscape.

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