Metamorphic rock: folded gneiss
A polished slab of decorative stone used as a floor tile in a downtown Calgary office building lobby.
High temperature during deep burial partly melted the precursor of this rock, segregating it into lighter (felsic) and darker (mafic) layers. Intense pressure then deformed the layers into small tight folds (amplitudes of approx. 5 to 10 cm) - the rock would have been soft and 'gooey' (viscous) at this point.
Copyright J.R. Devaney
Metamorphic rock: folded gneiss
A polished slab of decorative stone used as a floor tile in a downtown Calgary office building lobby.
High temperature during deep burial partly melted the precursor of this rock, segregating it into lighter (felsic) and darker (mafic) layers. Intense pressure then deformed the layers into small tight folds (amplitudes of approx. 5 to 10 cm) - the rock would have been soft and 'gooey' (viscous) at this point.
Copyright J.R. Devaney