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Petrified Forest NP

GLY 3164, Spring 2006

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Park Map

• Park is basically two units

• Painted Desert is to the North

• Petrified Forest is in the south

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Multi-Colored Ash Layers

• In the Painted Desert Region

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Petrified Logs

• Volcanic ash is visible in background• Along Straight Logs Trail

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Painted Desert Overlook

• Spectacular view of the extremely colorful Chinle formation, exposed in the Painted Desert

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Painted Desert

• Note spacing of vegetation, indicating very arid conditions

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Painted Desert View

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Colorful Logs

• Small amounts of impurities in silica create very colorful displays

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Petrified Log Video

• Close-up of the log, showing excellent preservation of the log structure

• Double-click to play video

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Log in the Blue Mesa Region

• Blue Mesa is composed of bentonite clay, a weathering product of volcanic ash

• Clay is very easily eroded

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Blue Mesa Overview

• Differential Erosion

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Log on Pedestal

• In the Blue Mesa Region

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Lithodendron Wash

• Small objects in the basin are petrified logs

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Petrified Logs

• Differential erosion uncovers the locks, because they are much more resistant to weathering than the soft Chinle formation in which they are found

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Petrified Log in Painted Desert

• Log has helped to preserve the easily eroded ash underneath it

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Agate Bridge

• Agate bridge has now been supported by the NPS to protect it, but originally spanned a small dry wash

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Giant Logs

• Along the Giant Logs trail

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Broken Log

• Many large logs break at regular intervals

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Petrified Forest Logs

• Montage of video clips

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Newspaper Rock

• In the Painted Desert section

• Rock writing was sometimes used to leave messages

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Pictoglyphs

• Rock is dark colored because of desert varnish• Scraping rock reveals the true rock color, and makes writing or

drawing possible • Many such writings were left by prehistoric Native Americans