Temple Butte Formation
The thin Devonian dolomite that fills ancient channels in the Muav — a survivor of the Grand Canyon's great Cambrian-to-Mississippian gap, bearing early fish.
Also known as: Temple Butte, Temple Butte Limestone
Devonian — the age of fishes
The world back then
Devonian, about 383 million years ago. Out west a shallow sea covers a tidal shelf; out east, tidal channels cut into the older limestone and fill with purple-gray mud. Fish with jaws are just getting going. It's a thin, patchy, in-between world — a survivor from a stretch of time the Grand Canyon otherwise skipped entirely.
Now it's a purplish rock that comes and goes along the wall, and you cruise by it, unhurried. A whole geologic period survives here by filling potholes — and you get to notice it from a boat, doing nothing. The luck of the late, cushy arrival strikes again.
Recognize it in the field
- Typical color
- purple/reddish-purple to gray
- Weathers as
- In the eastern canyon, thin, inconspicuous channel-fill lenses in the Muav; in the western canyon, a thicker continuous ledge that merges with the Redwall above.
Look for
- discontinuous paleochannel fills (east) vs a continuous unit (west)
- purple/gray dolomite
- marks a ~100+ Myr gap in the section
- easily overlooked
How this rock was made
A west-to-east Devonian marine rising sea drowning the land (transgression); the eastern lenses are channel fills.
The setting: shallow just below the tideline (subtidal) open-marine (west); tidal/estuarine channels (east)
0 (absent) to <100 ft (eastern lenses) to ~450 ft (western, continuous).
In the rock record
↑ Younger — rests above
↓ Older — sits beneath
Where to see it
Regions: Grand Canyon
- Temple Butte and eastern-canyon channel lenses
- continuous exposures in the western Grand Canyon
Float past it: Grand Canyon