The Painted Desert of northeastern Arizona is an aptly named land of colorful, stratified rock layers and easily erodible soils. Much of the Painted Desert is contained in Arizona’s Petrified Forest National Park, where this photograph was taken. Image credit: Nick Zantop
This magnificent desert badlands was formed by the erosion of siltstone and shale from the Triassic Chinle Formation. Abundant iron and manganese compounds in these finely-grained layers pigment the soil in vibrant hues.
The Painted Desert and Petrified Forest National Park are also famous for their rich fossil history. Beginning about 60 million years ago, the Colorado Plateau was pushed upward by tectonic forces, exposing what’s now Petrified Forest National Park to increased erosion.
Virtually all the rock layers above the Chinle Formation have been eroded by wind and water, exposing many of the fossils preserved in the Chinle sediment. In addition to huge quantities of colorful petrified logs, Triassic faunal remains have been found here as well, including Buettneria, salamander-like amphibians that grew to 10 ft (3 m) in length and phytosaurs, semi-aquatic, Late Triassic archosaurs, related to modern day crocodilians. Note the glaciating cloud and fall streak at top left. Photo taken on September 8, 2011. Summary Author: Nick Zantop