The end result was the striped and banded rock - visible in many parts of the canyon today - called gneiss. 12 to 5 million years ago Rocks in the area, which was still being pulled apart, became ...

Banded with colorful, unique garnets, the gneiss — a form of metamorphic rock — was pushed as far as rock can go before it melts, to 1,800 degrees Fahrenheit (1,000 degrees Celsius ...

LONDON. Geological Society, March 28.—Dr. H. H. Thomas, vice-president, in the chair.—E. Greenly: Further researches on the succession and metamorphism in the Mona complex. Fragments from the ...