GNEISS - Norway

GNEISS

1.5 to 1.85 billion years old

Bergen, Norway

A good example of the metamorphic rock gneiss.
 
Gneiss (pronounced 'nice') is formed under the extreme conditions that exist beneath mountain ranges and in the collision zone between continental plates.  The very high temperatures and pressures enable the rock to  change completely and new minerals to crystallise. 

This rock may originally have been a sedimentary rock.  The hot rock became soft as it approached melting point. If it had melted completely it would, on cooling, have become a granite.

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