Supai Group
The cyclic red-bed Pennsylvanian–Permian package of the middle Grand Canyon — four formations that build the Esplanade Platform between the Redwall and the Hermit.
Also known as: Supai
Paleozoic — ancient sea life, from the first shells to the first forests
The world back then
Late Pennsylvanian into Permian, around 300 million years ago. A broad coastal plain — think the modern Texas Gulf Coast — with sluggish rivers, red mudflats, encroaching dunes, and shallow seas washing in and out in long cycles. Hot, low, and red, the shoreline sliding back and forth for millions of years. Four formations' worth of the same restless coast.
Those restless cycles are the red stair-steps of the Esplanade, and the current walks you smoothly through all four chapters. The coast couldn't sit still for millions of years; you don't have to lift a finger. Warm, comfortable, and carried — the deal keeps being absurd.
Recognize it in the field
- Typical color
- red (red beds)
- Weathers as
- Alternating cliffs and slopes / ledges — each of the four formations is a lower cliff over an upper slope; the Esplanade Sandstone caps the Esplanade Platform.
Look for
- four stacked formations, each with internal unconformities
- cyclic — oscillates continental (eolian) to shallow-marine
- marine westward, terrestrial eastward
- the Esplanade Sandstone forms the Esplanade Platform
How this rock was made
A broad coastal plain (likened to the modern Texas Gulf Coast) with repeated rising-sea (transgressive)-falling-sea (regressive) cycles and encroaching dunes.
The setting: broad coastal plain with dune fields and shallow seas (cyclic)
~680–1,250 ft at the Grand Canyon (summing the four formations).
In the rock record
↑ Younger — rests above
↓ Older — sits beneath
Where to see it
Regions: Grand Canyon / Colorado Plateau
- the Esplanade Platform, Grand Canyon
- Havasu Canyon (type section) near Supai village
Float past it: Grand Canyon