A geologist discovers a new rock formation. The rock is dark in color and appears to have formed layers. The layers are thick and not parallel but instead show some folding
The metamorphic rocks are transformed from the existing rock types. They change with the changes in pressure and temperature. They cover large parts of the earth's crust make up 12% of the earth.
They are made by tectonic processes such as continental collision. That leads to horizontal pressure and distortions some examples may include the gneiss, marble, slate, schist, and quartzite.
