Kayenta Formation, Geological formation in southern Utah and northern Arizona, United States.

The Kayenta Formation is a dark-red, maroon or lavender band of thin-bedded sandstone, shale and limestone lying between the Wingate Sandstone below and the Navajo Sandstone above. Its weak beds form a bench or platform, and the sandstone layers, from under 25 mm to over 3 m thick, are coarse quartz grains cemented by lime and iron.

The Kayenta Formation was deposited during the Early Jurassic, with detrital zircon dating giving an age of 183.7 ± 2.7 Ma, though samples from Colorado and Arizona suggest 197.0 ± 1.5 to 195.2 ± 5.5 Ma. Its sandstones, shales and limestones record shifting streams of fluctuating volume, and the topmost beds may approach the Toarcian. Fossil mudcracks and thin limestones mark seasonal ponds and lakes.

The formation's fossils include amphibians, anapsids, crocodylomorphs, ornithodirans and synapsids, groups studied by palaeontologists working on the Glen Canyon Group. Visitors can see fossil mudcracks and thin limestones in the rock, and in Zion's Pine Creek Canyon the channel and flood-plain deposits of ancient streams are exposed on the switchbacks below the tunnel.

You can observe it best in Zion, Capitol Reef, and Canyonlands, where the layers are clearly visible on canyon walls. Visiting is possible year-round, but spring and fall offer the most comfortable hiking conditions.

The layer holds fossilized footprints of early dinosaurs and remains of freshwater creatures like mussels and snails. These discoveries reveal that the region once teemed with ancient water systems where life thrived.