Petrified Forest National Park
During the Triassic Period, 225 million years ago, Arizona was a subtropical forest just a few degrees north of the equator. Back then, North America was still part of the supercontinent called Pangea that included South America, Europe, and Africa. The landscape was hot and humid with abundant vegetation while early dinosaurs and reptiles roamed the forests. Giant 180-foot conifers reached the skies. Over the next 200 million years, Pangea split apart and Arizona slowly moved 2,100 miles north through the process of plate tectonics. The climate changed dramatically to the desert grassland seen today in Northern Arizona.
Back over 200 million years ago when Northern Arizona was a subtropical forest, large river raged, and they frequently undercut the roots of living and dead trees. These trees toppled into the water and soon were buried under sand and mud of the river channel. By being buried, the trees were deprived of bacteria and oxygen thus preventing decay. Eventually silica in the ground water infiltrated the tree replacing the organic material with quartz crystals. Over time, the log turns to stone or becomes petrified. Over millions of years, erosion of the surrounding material re-exposes the petrified log. Further erosion undercuts the log causing it to crack, break into segments, and eventually shift and roll into its present position.
By the late 1800s, interest in the petrified wood was threatening this landscape. The Arizona Territorial legislature petitioned Congress in 1895 to protect this valuable scientific and cultural treasure. In 1906, President Theodore Roosevelt signed legislation creating Petrified Forest National Monument which became a national park in 1962. In the early days of the national park, visitors would arrive on the Santa Fe Railroad. The opening of Route 66 in 1926 brought the motoring public right to the national park. In fact, Petrified Forest National Park is the only national park that Route 66 passed through. Modern visitors arrive at the northern entrance on I-40 or to the southern entrance via US-180.
Petrified Forest National Park is the best place on Earth to see a prehistoric forest, now petrified, and it also boasts a treasure of animal and plant fossils. Most of the petrified trees in the park are over 210 million years old. The rainbow of colors seen in the petrified trees comes from the mineral impurities within the quartz. While pure quartz is white, iron oxides within the quartz attributes for red, yellow, orange, and purple. Manganese oxides in the quartz yields the colors of black and grey. Two of the best places in the park to check out the petrified logs are the Giant Logs and Crystal Forest trails which are right off the park’s main 28-mile road.
There is over 13,000 years of human history in Petrified Forest National Park with more than 1,000 archeological sites in the park. The Paleoindians (13,500–8,000 BC) were a nomadic group that hunted large animals (bison, mammoths) and utilized petrified wood to make projectile points. They were followed by the Basketmakers (500 BC–650 AD) who settled in the region, building pit houses and developing agriculture growing corn, squash, and beans. The Ancestral Puebloans lived in the park until around 1450 AD living in above-ground masonry dwellings (pueblos) and leaving behind numerous petroglyphs. The Puerco Pueblo near the Puerco River was a 100-room one-story pueblo complex with a central plaza and numerous kivas. On the rocks below the pueblo, the people who lived there left behind numerous petroglyphs. Another great site for petroglyphs within the park is at Newspaper Rock where you can view dozens of rock drawings from an overlook.
The northern region of Petrified National Park borders the Painted Desert of northeastern Arizona. The Painted Desert is a vast, colorful badlands landscape that stretches from the Grand Canyon southeast to the Petrified Forest National Park. The park road has numerous panoramic overlooks for taking in the breathtaking colors of banded hills of red, orange, and blue-grey shale. The Painted Desert Inn was built in the Pueblo Revival style in the early 20th century to offer accommodations for visitors to the national park. Today it is a National Historic Landmark and a museum with exhibits on its history and architecture.
