From the Road: Whipple Mountains

Savahia Peak in the Whipple Mountains, with cholla.

And here's a cartoon of the geology.

The upper plate volcanic rocks are dipping moderately to steeply to the west (cyan bedding). The Whipple Mountains detachment fault (hachured dark blue) is fairly flat-lying in this area, separating reddish, hematitic upper plate rocks from greenish, lower plate chloritic and mylonitic gneisses. I've drawn in a few approximately located listric normal faults in bright blue to illustrate the general structural configuration. The upper plate has moved to the east relative to the lower plate, as indicated by both the dip of beds in the upper plate, and (especially) by the movement on upper plate listric normal faults.