National Park Service Petrified Forest U.S. Department of the Interior Petrified Forest National Park Arizona

Trees to Stone

An enchanted spot…to stand on the glass of a gigantic kaleidoscope, over whose sparkling surface the sun breaks in infinite rainbows. ~~Charles F. Lummis, Some Strange Corners of Our Country – A Forest of Agate, 1891.

Triassic Environment During the Late Triassic Epoch, over and other creatures. In the slightly 200 million years ago, northeastern dryer areas a short distance from the Arizona was located near the equator. water there are cycads, bennettitaleans, This region was near the southwestern ginkgoes, and coniferous trees. edge of the earth’s largest existing landmass, Pangaea. The tropical Over time, trees died or were knocked location resulted in a climate and down by wind or the action of water. environment very different from today. Rivers and streams carried the trees Eventually the super-continent broke downstream, breaking off branches apart into the modern continents. Fossil and roots along the way. Many tree evidence of this ancient land lies in the trunks came to rest on the banks of sediments called the Chinle Formation the rivers while others were buried now so widely exposed in Petrified in the stream channels. Most of the Forest National Park. trees decomposed and disappeared, but some of the trees were petrified, Imagine a large basin with numerous becoming the beautiful fossilized logs rivers and streams flowing through we see today. Some of the fossilized logs the lowland. A lush landscape with are from a tree called Araucarioxylon coniferous trees up to ten feet in arizonicum. Two others, Woodworthia diameter and towering almost two- arizonica and Schilderia adamanica, hundred feet into the sky surround mostly occur in the northern part of you. Galleries of trees, ferns, and giant the park. Overall at least nine species horsetails grow abundantly along the of fossil trees have been identified from waterway, providing food and shelter the park; all are now extinct. for many insects, reptiles, amphibians, Petrification Some logs were buried by sediment occasionally, the internal cell structures. before they could decompose while Iron and other minerals combined volcanoes far to the west spewed tons with quartz during the petrification of ash into the atmosphere. Winds process, creating the brilliant rainbow carried ash into the area where it was of colors. Iron minerals provide bright incorporated into the thickening layers mustard, orange, rich reds, ochre, and of sediment. Ground water dissolved black. Blue, purple, brown, and black, silica from the volcanic ash and carried including graceful fern-like patterns, it through the logs. This solution filled are caused by manganese minerals. the cells, eventually replaced the cell Sometimes crushing or decay left walls in some cases, crystallizing as cracks in the logs. Here the growth of the mineral quartz after a very long quartz crystals was not limited and time. The process was sometimes so larger crystals of clear quartz, purple exact the resulting fossils show many amethyst, yellow citrine, and smoky details of the logs’ original surfaces and, quartz formed.

Uplift and Erosion This area has endured many changes. Since petrified logs are composed As time passed, the Chinle Formation of quartz, they are hard and brittle, was buried by a thick sequence of breaking easily when subjected to younger rock. About 60 million years stress. The hard logs are surrounded ago the region was uplifted as part of by softer sedimentary layers. As the the massive Colorado Plateau. Over sediments shifted and settled, as well as time, many rivers and storms eroded the tectonic movement, stress on the rigid land, removing the younger layers of logs caused fractures. Some researchers rock until parts of the Chinle Formation believe that such stress may have been were exposed. Now fossilized logs that produced by earthquakes or the gradual were once embedded in the Chinle uplifting of the Colorado Plateau. Formation lie strewn across the badland hills and are exposed in cliff faces. You Erosion continues today. Rain and might notice that most of the logs are wind wear away the land, uncovering broken into segments. Who cut the additional logs, while freezing and logs? This is one of the park’s most thawing break down the logs exposed common questions! People did not on the surface. With the infinite cut the logs. Because the sections are patience of time, the layers of sediment still in order, we know that the logs will continue to erode, exposing more fractured after they were buried and pages of this ancient history book. the petrification process was complete.

More than Trees While the park is best known for its silicified wood, compressed leaves, petrified trees, the Chinle Formation stems, cones, pollen, spores, and is full of different kinds of fossils and amber. Plant groups represented is considered one of the richest Upper in the park include lycopods, Triassic fossil plant deposits in the ferns, cycads, conifers, ginkgoes, world. Over 200 fossil plant taxam bennettitaleans, and several forms that including more trees, are known are currently unclassified. from the Chinle Formation, including

Your National Park Petrified wood is found in every state All natural and cultural resources and in many countries, so why was this such as petrified wood, rocks, fossils, place made into a national park? It artifacts and plants must not be was originally established to protect removed from the park. Unfortunately, some of the largest and most beautifully thoughtless people continue to steal preserved concentrations of petrified tons of petrified wood from the park wood in United States. We now know, every year. Petrified wood sold in local however, that few places in the world shops does not come from the park. It have a fossil record of the Triassic is obtained from private lands outside Period that is so diverse and complete. the park boundaries. These things make your park special.

Everyone is responsible for protecting the national parks. Do not allow thoughtlessness to damage your irreplaceable heritage. Please report wood theft by using the emergency phones at Blue Mesa, Puerco Pueblo, and Crystal Forest or speaking with a park employee.

January 2011 EXPERIENCE YOUR AMERICA Visit our website at http://www.nps.gov/pefo