Wednesday, January 30, 2008

Geology in your backseat

Are you planning a vacation somewhere in the United States? Before you leave on your next trip, be sure to take along some geology. Roadside Geology guides are available for a number of U.S. locations. Road cuts provide a wonderful opportunity to take a peek at what’s normally hidden deep beneath the earth’s surface.

Weeping rock of the Boone Formation
Photo credit: Roxnoil

Along the highways of Missouri, you often see weeping limestone faces -- like the one shown above -- due to the porous nature of this sedimentary rock. These seeps can be especially beautiful when they freeze in the wintertime, forming dripping white icicles instead of appearing as dark streaks.

Pinnacles National Monument, California

Photo credit: National Park Service
(Note: If you tip your head to the left, the parallel lines in the rock look horizontal. That gives you a sense of how much the rocks have been displaced (moved) over time.)

Driving through the canyons of Utah, rock layers sometimes appear vertical instead of horizontal due to uplift (see photo above for an example of this in California).

Lava flow near Kalapana, Hawaii (June 1990)

Photo credit: U.S. Department of the Interior, U.S. Geological Survey
Check out the USGS Lava covers Kalapana for more great images!

And if you are exploring the Big Island of Hawaii, some of your intended highways may have been covered by lava flow – a prime example of geology in action!

Learn more about U.S. geology by visiting the United States Geological Survey or drop by the Association of American State Geologists and click on the map to visit each state’s own Geological Survey.

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