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Devils Postpile National Park Geologic Story

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Curved Columns
Curved columns
Curved columns. Photo by Wymond W. Eckhardt, NPS.

spacer image Most of the columns in the Devils Postpile diverge from the vertical as though tilted and some are even curved as if they had been bent. Under ideal conditions, the long dimensions of basalt columns develop at right angles to the cooling surfaces. If a lava flow is homogeneous in chemical composition, of uniform thickness, and has level top and bottom cooling surfaces, then, theoretically, the flow cools uniformly into vertical columns. All of these factors were not fulfilled in the Devils Postpile flow, however, causing irregularities in cooling and consequently producing curved posts with various number of sides.
spacer image The exceptional aspect of the Devils Postpile is not that some columns are curved, but that in places the lava was homogeneous enough and had a cooling rate uniform enough to have produced many columns so long and regular.

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http://www.nature.nps.gov/grd/usgsnps/depo/dpgeol8.html
This page was last updated on 9/7/00
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Material in this site is adapted from a pamphlet, Devils Postpile Story, by N. King Huber, USGS, and Wymond W. Eckhardt, NPS. It is published by Sequoia Natural History Association, Sequoia Natural History Association, HCR-89, PO Box 10, Three Rivers, CA 93271-9792, Telephone (559) 565-3759