Photo #3

gneiss_breccia

The mylonitic gneiss is thoroughly brecciated although the compositional layering is still evident.
Angular pieces are spaced on the order of centimeters apart.
Small-scale normal faults with displacements up to 10 centimeters also disturb the gneiss.
These rocks have a green tint, indicating that some chlorite alteration has probably taken place.
East Saguaro National Park, southern Arizona. View looking NE. Pencil in upper right for scale.

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