If you're going to California, be sure to put some of these geologic attractions on your must-see list.
You might not think of the Golden State as a volcanic wonderland, but it surely is. Here are just a few of the most noteworthy places.
Medicine Lake volcano is a subdued caldera in the northeastern highlands, full of diverse volcanic landforms including spectacular lava tubes. It's preserved in Lava Beds National Monument.
The Morros, near Morro Bay and San Luis Obispo, are a chain of nine volcanic necks, remnants of ancient seafloor volcanoes. There's nothing else like them—and there are also beaches and a haunted hotel.
Devils Postpile is a good destination if you want a break from climbing in the Sierra Nevada. It's a textbook locality for columnar jointing, which happens when a thick body of lava slowly cools and naturally fractures into hexagonal columns like a box of pencils. Devils Postpile is in a National Monument.
Fossil Falls lies in the desert beyond the Sierra, a place where a now-vanished river scoured flows of basalt lava into fantastic shapes. Combine it with a visit to Manzanar and other highlights of the Owens Valley. More young volcanoes sit in the Mojave south of Baker.
In the San Francisco Bay area, Oakland's Round Top is a dissected volcano exposed by quarrying and preserved as a regional park. You can even get there by city bus.
Death Valley is one of the world's premier localities for seeing fresh crustal extension, which has dropped the valley floor below sea level. Death Valley is a National Park and a nice day trip from Las Vegas.
Owens Valley is a tremendous graben, downdropped between the Sierra Nevada and the White Mountains. It's also the site of the great 1872 earthquake. Just a couple hours' drive away is the hauntingly familiar Red Rock Canyon State Park.
Point Reyes is a large chunk of land that has been carried on the San Andreas fault (along with Bodega Head) all the way up from southern California beyond San Francisco. That displaced crustal block is in a National Park. For a real geologic thrill, see Point Lobos near Monterey, almost 200 kilometers away, where the same rocks appear on the fault's other side in a state park.
The Transverse Ranges are a great discontinuity in the fabric of California and one of America's most dramatic landscapes. State Route 99/Interstate 5 over the Tejon Pass, between Los Angeles and Bakersfield, will take you across it. Or take a similar trip on State Route 33, farther west.
Lake Tahoe is a large downdrop basin in the High Sierra, filled with one of America's finest alpine lakes, and is also a prime playground at all times of year.
Subduction-related rocks are widespread in California, where decades of leading research have not exhausted the knowledge to be gained or the enjoyment to be had from these unsung witnesses to plate tectonics.
Beaches, coastal cliffs, and estuaries up and down the state are scenic treasures and geologic lessons. See my selection of geologically interesting places. And for more, Explore California's Coastal Geography on this state government site.
Beaches need no introduction, but there's more to them than sand and sea. Laguna Beach in the south and Stinson Beach and little Shell Beach in the north are examples that are full of geological interest.
Other Geologic Features
The Central Valley may seem like something to drive through as fast as possible on your way somewhere else, but it's full of geological interest if you take the time to poke around.
The Channel Islands are known to geologists as the California Continental Borderland—and a brand-new National Park.
Petroleum is a big part of California geology. Visit a natural oil seep at Coal Oil Point in Santa Barbara, the spectacular tar seeps at nearby Carpinteria Beach or the famous tar pits of Rancho La Brea in Los Angeles. In the southern San Joaquin Valley, drive through the Kettleman Hills to see the heart of the industry—in fact, the original asphalt seep at McKittrick and the site of the great Lakeview oil gusher are just off the highway.
What is a desert without sand dunes? The booming Kelso Dunes are an essential stop in the Mojave, south of Baker. If you're nearer Mexico, try the Algodones Dunes instead. They're the largest dunefield in California.
Yosemite Valley, home of Half Dome, is an unforgettable collection of landforms created by crustal denudation and glacial action. It's also the world's first place set aside to become a National Park.
For more ideas, see the California Geology category