Rocks that crop out in the internal zones of the Alps were once deeply buried.
We know this because the original character of the rocks (e.g. sediments or
igneous) has been altered - metamorphosed. Although the bulk composition of
the new rocks may have remained unchanged from that of the precursor - new minerals
have replaced the old ones. We know the conditions under which the reactions
occur and so can reconstruct the temperature and pressure of the metamorphic
rocks. If we can tell when the minerals grew relative to deformation, then we
can tell under what conditions the deformation happened. Click on the icons
to see some examples of metamorphic rocks from the Alps.
