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Group · sandstone

Glen Canyon Group

The Triassic–Jurassic cliff-and-slickrock package of the Colorado Plateau — Wingate, Kayenta, and Navajo (plus Moenave), the units that build canyon country's most iconic walls.

Also known as: Glen Canyon

Mesozoic — the age of dinosaurs

The world back then

Early Mesozoic, roughly 200 million years ago, and the whole world is drying out. You watch it happen in fast-forward: Triassic rivers and floodplains give way to a ledgy, braided plain, and then to nothing but dunes — the great Navajo desert swallowing everything. Wetter to drier, river to sand, cliff to slickrock, on the western edge of Pangaea.

You get the reverse trip, the easy way — riding a cool current past the stack that recorded a landscape dying of thirst. Those rocks lived through a drought that lasted millions of years; you cross the whole thing between lunch and camp. The luck of it is almost embarrassing.

Recognize it in the field

Typical color
red to pale — red Wingate, maroon Kayenta, white-to-salmon Navajo
Weathers as
A stacked cliff–ledge–slickrock sequence: sheer Wingate cliff, ledgy Kayenta bench, and rounded Navajo domes and walls.

Look for

  • the classic Wingate–Kayenta–Navajo cliff stack of canyon country
  • records the drying of the region from rivers to a dune sea

How this rock was made

Spans the transition from Late Triassic river floodplains to the vast Early Jurassic Navajo sand sea (erg) on the western margin of Pangaea.

The setting: river (fluvial) to wind-blown (eolian) (an aridifying Early Mesozoic landscape)

Group thickness is the sum of its members and varies strongly across the plateau; see the component units.

In the rock record

↑ Younger — rests above

Carmel Formationa gap in time (unconformity) · much of the Colorado Plateau
Glen Canyon Group you are here
Chinle Formationmost of the Colorado Plateau

↓ Older — sits beneath

See the full regional rock columns →

Where to see it

Regions: Colorado Plateau

Float past it: Westwater Canyon · Meander Canyon · Stillwater Canyon · Labyrinth Canyon