|About the Site|
|Petrified Forest National Park (Petrified Wood)|
Petrified Forest National Park contains one of the world's most spectacular collections of petrified wood. Remnants of giant trees from ancient forests of the Triassic Period over 200 million years old, these logs turned from wood to rock after the trees were buried under layers of sand and silt. In some cases, the microscopic structure of the wood was preserved during the process, as can be seen below.
In other cases, the cellular structure of the wood was entirely lost, as in the example below.
In many places small sections of logs lay scattered about the ground, as in some of the examples below. John Muir called the area "a kaleidoscope fashioned by God's hand." As can easily be seen, the petrified wood displays a variety of colors resulting from the minerals it contains--pine quartz for white and gray, iron for the reds and yellows, browns, blues, and greens, and carbon and manganese for the black.
Another sample of petrified wood is shown here.
The petrified wood, not unexpectedly, is much heavier than the original log, weighing as much as 150-200 pounds per cubic foot.
An interesting sample is shown here.
Most of the petrified logs in the park were from trees of the variety Araucarioxylon, large trees which reached 100 feet in height and 6-8 feet in diameter.
In other places sizeable sections of the original tree still exist in on piece, as in the example below from the Giant Logs area.
An event more interesting example, Agate Bridge, is shown on the right. This petrified tree originally lay flat on the ground until the arroyo which now runs beneath it was formed by erosion. The log bridge was shored up with the concrete support in 1917, perhaps preserving the bridge but adding nothing the genuine nature of the feature.
Rainbow Forest & Giant Logs
In the southern section of the park lies the Giant Logs and Rainbow Forest collections of petrified wood. These areas contain a wide variety of different specimens, many laying randomly about the ground.
The half-mile long Giant Logs Trail provides visitors with an easy way to get a close view of the many specimens in the area, as can be seen in the pictures below.
A paved section of the trail is shown here.
Because of the unevenness of the ground and the need to preserve the rock specimens there is a paved trail and steps.
Another of the most well-known areas for observing specimens of petrified wood is the Crystal Forest. This area contains some large specimens of trees which have broken into constituent parts. The .79 mile trail which runs through the area provides excellent vantage points to view the wood.
Because of the arid nature of the area and the absolute lack of trees given the current climate it can be difficult to picture the lush woodlands which existed in these areas in Triassic times. An idea of just how large the original trees must have been can be gathered from the fallen trunks as they lay on the ground. The cracks which divide most of the logs into sections are due to stress on the log.
As the land erodes around the trees they may eventually break and roll down the including, appearing as if they were scattered in that area.
More scattered samples are seen here.
Information about Petrified Forest National Park has been drawn from personal experience, data available in the park itself, and a number of other sources, including:
- Ash, Sidney. Petrified Forest: The Story Behind the Scenery. Petrified Forest National Park, AZ: Petrified Forest Museum Association, 1986.
- Bezy, John V., & Trevena, Arthur S. Guide to Twenty Geological Features at Petrified Forest National Park. Holbrook, AZ: Petrified Forest Museum Association, 1975.
- Bowman, Carl, & Bowman, Lori. In Pictures: Petrified Forest, the Continuing Story. Las Vegas, NV: KC Publications, 1991.
- Hauk, Rose. The Painted Desert: Land of Light and Shadow. Petrified Forest National Park, AZ: Petrified Forest Museum Association, 1990.
- Jones, Ann Trinkle. Stalking the Past: Prehistory at the Petrified Forest. Petrified Forest National Park, AZ: Petrified Forest Museum Association, 1993.
- National Geograhic's Guide to the National Parks of the United States. Washington, DC: National Geographic Society, 1992.
- National Parks of North America. Washington, DC: National Geographic Society, 1995.
- Our National Parks. Pleasantville, NY: Reader's Digest Associates, 1989.
- The Sierra Club Guides to the National Parks: Desert Southwest. New York: Stewart, Tabori, & Chang, 1996.
- Trimble, Stephen. Earth Journey: A Road Guide to Petrified Forest. Petrified Forest National Park, AZ: Petrified Forest Museum Association, 1984.
- First Page for Petrified Forest National Park -
- All photographs ©Patrick Holleran, Shannon Digital Imaging, 1994-2013
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