File:Blue Mesa- A shift in Color.jpg

English: The colors were different, the shadows formed other patterns. In the light of morning, you see the banding of soft grey, subtle purple, clear blue, faint pink, even an elusive green. For the artist, this was beauty.

The colorful bands of the Chinle Formation represent ancient soil horizons. While the red, blue, and green layers generally contain the same amount of iron and manganese, differences in color depend on the position of the groundwater table when the ancient soils were formed. In soils where the water table was high, a reducing environment existed due to a lack of oxygen in the sediments, giving the iron minerals in the soil a greenish or bluish hue, such as at Blue Mesa. The pink and reddish layers were formed where the water table fluctuated, allowing the iron minerals to oxidize (rust).

Blue Mesa @ Petrified Forest National Park, Arizona