The Mixed Rock Unit

Schist with minor amounts of interlayered amphibolite and quartzo-feldspathic gneiss

Although the mixed rock unit at Elk Knob is composed primarily of schist (>95%) that is typical of the Ashe Metamorphic Suite, this unit as mapped as the mixed rock unit because it locally contains discontinuous layers of amphibolite interlayered with semischists and quartzo-feldspathic gneisses (a light colored, metamorphic rock characterized by weak metamorphic layering and has less mica compared to schist).

 

 

 

 

Close-up viewof outcrop pictured above showing garnet-bearing amphibolite interlayered with quartzo-felspathic gneiss.

This particular outcrop is not only the best exposed example of interlayered amphibolite and gneiss within the mixed rock unit, but it also contains many clues to the deformation history of Elk Knob. Complex fold patterns like this support multiple stages of folding during mountain building.

Triassic Sandstone