The Petrified Forest: Wood That Turned to Stone

About twenty-five miles east of Holbrook, Interstate Forty passes through the northern edge of Petrified Forest National Park. The intersection is marked by an overpass and two park entrances, north and south. Most people drive through without stopping.

They should stop. The Triassic-era logs that have been replaced, molecule by molecule over two hundred twenty-five million years by silica-bearing groundwater, are lying on the ground in the open desert in pieces that look freshly cut and are in fact ancient beyond most human intuitions about time. The colors, reds and purples and yellows and whites, come from trace minerals that substituted for the original organic material as petrification proceeded.

The logs are not wood. They are rock that is organized exactly like wood. The Painted Desert, which forms the northern section of the park and extends well beyond it, is a badlands formation of Chinle Formation mudstone, deposited in the same Triassic period and now eroding at a pace measurable in inches per year.

The colors that give it the name shift through the day as the sun angle changes. At dawn and dusk the purple and orange are extreme. The Ancestral Puebloan people left petroglyphs and habitation sites throughout the park.

The Navajo Nation borders the park to the north. The Hopi mesas lie to the northwest. This part of the Colorado Plateau is among the most densely storied landscapes in North America, layers of Indigenous culture going back more than two thousand years, on top of a landscape that is itself a record of an entirely different world.

The park admission is valid for seven days. The south visitor center is right at the Interstate Forty interchange.