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The bulk of the Zuhl Geological Collection is composed of petrified wood ranging in size from twigs and stems a few centimeters long to logs over a meter in diameter. Although there are specimens of wood from all over the world, most come from three regions in the United States. Perhaps the most famous is petrified wood from northern Arizona, extracted from the Chinle Formation of Late Triassic age (~220 million years ago). Wood from the Chinle Formation represents conifer trees and is noted for vibrant red and yellow colors. (Photos by Stephanie Furgal) |
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Four tree stumps replaced by silica. |
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Growth rings can still be seen even after wood replacement |
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"Slice" of a large conifer |
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Geology Department professor Dr. Greg Mack displays two petrified logs taken from the Chinle Formation of Arizona. |
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Colorful bands of silica
have replaced the wood from this conifer. Different elements have
created the colors you see here.
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