Eutaxitic texture in ignimbrite of the Cat Mountain Rhyolite, Tucson Mountains, Arizona


I collected this near Gates Pass in the Tucson Mountains in 2008.  I like the fresh nature of this rock, the slabby (fracture-controlled) form, and the conspicuousness of the eutaxitic structure.  It is good to have an example of foliations that are “primary” in nature, and not created through metamorphism.  

Age & Formation
Cat Mountain Rhyolite, ~70 Ma.