Grand Canyon River Guides

Tell Me Why
Management Plan
Modus Operandi
Overflights
Poison Information
The EIS: Past and Future
The River Wild
Adaptive Management
Kingman Wins!
Non-Native Fishes of GC
River Sociology
Autumn Extravaganza
Atmospheric Optics
Greetings From the Ferry
Ravenna Grass
Poems
 
the journal of Grand Canyon River Guides, Inc.
volume 6   number 4                              fall 1993



Stress and Strain:
Squashing Rocks in the Muav Gorge


   Chuck Barnes of NAU Geology suggested that a geologist should seek out a beautiful field area first, and ask questions later. I took him at his word; while stumbling through a master’s at Stanford, I chose the Grand Canyon for a thesis area.

   Perhaps you’ve noticed the folds and faults in the Muav at river level near Kanab Creek. The folds come in a number of different flavors: wavy thin-bedded limestones that hang above the river around Last Chance; or stubby little “kink bands”, where an eight- or ten-foot segment of bedding is suddenly tipped twenty or thirty degrees steeper than the surrounding rock. Consider the limestone immediately upstream of Olo; a thrust fault blasts out of that wall with all the impatience of a locomotive leaving its tracks. In some places, the deformation is more subtle: walk down a side canyon like Matkatamiba, and you will see beds bend

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