OK, let's make this an interactive Geology Picture of the Week. Post other nice pictures of columnar jointing! (Devil's Tower, Yellowstone National Park, Devil's Postpile, and the Palisades of New York are some examples, but I'm sure there are more.)
1 posted on 12/14/2004 8:18:05 AM PST by cogitator
More Postplie. The glacial polish across the top is really cool, like walking on a tiled floor.
Photograph by C.D. Miller in 1980
These glacial striations are carved in the top of a columnar-jointed basalt lava flow. The lava flow was erupted between 200,000 and 100,000 years ago in the Middle Fork of the San Joaquin River valley. The lava flow was then eroded during subsequent glacial periods, as shown by the finely polished and deeply striated surface. This exposure is from along the trail at the top of the Devils Postpile in the Devils Postpile National Monument.
6 posted on 12/14/2004 8:32:11 AM PST by Slicksadick
(Go out on a limb........Its where the fruit is.)