Ancient Environments

The rocks that make up this landscape formed in environments that are very similar to ones we can observe on the earth's surface today as well as ones that occur beneath the surface where tectonic plates collide to form mountain ranges.

Kayenta Formation , The Kayenta Formation is a sandstone that is more resistant to erosion than many of the other sedimentary rocks in the park. The Kayenta Formation was deposited by a high-energy braided river system similar to the Rio Grande River in New Mexico.

Wingate Formation , The Wingate Formation is a tan sandstone whose sweeping tilted layers tell us that this rock was deposited in a desert environment where wind-swept sands accumulated and were buried. An environment like this can be found in the modern Sahara Desert of North Africa.

Chinle Formation , The Chinle Formation is primarily a reddish-brown mudstone that likely was deposited in densely-vegetated floodplains or mudflats with small ponds and streams. This environment is similar to the coastal environments in South America and Africa.

Precambrian Metamorphic Rocks , Dark schists and light pegmatites are the extremely erosion-resistant basement rocks found in the bottom of the Monument's canyons. These rocks began as sediments that were later deformed in mountain building processes. They were deposited, buried, heated, squeezed, uplifted and planed off by erosion - all before the sedimentary rocks of the Monument were deposited. Today, rocks like these are being formed and then deformed where tectonic plates converge. An example is along the western margin of South America.