When visiting Arizona, people often ask, “Where is the Petrified Forest National Park?” and “What is the Petrified Forest?” So, let’s take a walk back in time to learn about the Petrified Forest, how it formed, where it is located here in Arizona and things to do at the park for all ages. Did you know you there are backcountry hikes into areas never open before such as Red Basin and little known areas like the Martha’s Butte?
About Petrified Forest National Park
Petrified Forest National Park is known for its fossils, especially of fallen trees that lived in the Late Triassic period of the Mesozoic era, about 225 million years ago. During this period, the region that is now the park was near the equator on the southwestern edge of the supercontinent Pangaea, and its climate was humid and sub-tropical. What later became northeastern Arizona was a low plain flanked by mountains to the south and southeast and a sea to the west. Streams flowing across the plain from the highlands deposited inorganic sediment and organic matter, including trees as well as other plants and animals that had entered or fallen into the water. Although most organic matter decays rapidly or is eaten by other organisms, some is buried so quickly that it remains intact and may become fossilized.
During the Late Triassic, downed trees accumulating in river channels in what became the park were buried periodically by sediment containing volcanic ash. Groundwater dissolved silica from the ash and carried it into the logs, where it formed quartz crystals that gradually replaced the organic matter. Traces of iron oxide and other substances combined with the silica to create varied colors in the petrified wood.
In Petrified Forest National Park, most of the logs in the park retained their original external form during petrification but lost their internal structure. However, a small fraction of the logs and most of the park’s petrified animal bones have cells and other spaces that are mineral-filled but still retain much of their original organic structure.
Where is the Petrified Forest National Park?
Where is the Petrified Forest National Park? The park’s headquarters is about 26 miles east of Holbrook along Interstate 40 (I-40), which parallels the BNSF Railway’s Southern Transcon, the Puerco River, and historic U.S. Route 66, all crossing the park roughly east–west. The park is open every day except Christmas on a schedule that varies slightly with the seasons. Click here to learn about things to do at Petrified Forest National Park.