Painted Desert

The Painted Desert is a badlands region of banded sedimentary rock stretching roughly 160 kilometers across northern Arizona, including within Petrified Forest National Park. It is composed chiefly of the Triassic-age Chinle Formation, a sequence of mudstone, siltstone and volcanic ash beds whose varying mineral content, including iron and manganese oxides, produces the alternating bands of red, orange, pink, grey and lavender visible across its eroded hillsides. The same Chinle Formation famously preserves petrified wood from an ancient forest that was buried by volcanic ash and river sediment and gradually replaced by silica minerals, so the Painted Desert's colorful badlands and the petrified logs found within them share the same underlying rock unit and geological history.