The Painted Desert and a Very Old World
Near Holbrook, Arizona
The colors visible from the highway near Holbrook, the banded hills of red and pink and white and gray and lavender, are not decoration. They are chemistry. The Painted Desert is a region of exposed Triassic-era badlands where iron oxides produce the reds and yellows, manganese creates the purples and blues, and bleached volcanic ash separates the colored layers in between.
Erosion is ongoing and rapid by geological standards, and after a rainstorm the colors intensify until the hills seem to glow. The Chinle Formation, the rock layer responsible for most of the Painted Desert's color, was deposited roughly two hundred ten to two hundred twenty million years ago in a river floodplain environment near the ancient equator. It is the same formation that contains the petrified trees.
Walking across these badlands, you are walking on the compressed floor of a tropical lowland that no longer exists on this continent. Ancestral Puebloan people understood this landscape on its own terms and built their communities within it. The ruin called Puerco Pueblo, inside Petrified Forest National Park, was occupied in two periods, roughly eleven hundred to twelve hundred and again from thirteen hundred until about thirteen eighty, and its walls still stand in courses above the desert floor.
More than eight hundred petroglyphs have been recorded on the surrounding boulders, including a ringed design where, for about two weeks around the summer solstice, the rising sun's light and shadow move across the rings. The desert has always been full of intelligence. Some of it is very old.
