Metamorphic rocks originate from pre-existing rocks that undergo transformation due to heat, pressure, and mineral changes. The primary rock groups that can form from metamorphic rocks include:
- Foliated Metamorphic Rocks: These rocks exhibit a layered or banded appearance due to the alignment of mineral grains. Common examples include schist and gneiss, which can form from shale and granite, respectively.
- Non-Foliated Metamorphic Rocks: Unlike foliated rocks, non-foliated metamorphic rocks do not show layering. They are typically formed from the metamorphism of rocks like limestone or sandstone. Notable examples include marble, which comes from limestone, and quartzite, which originates from sandstone.
Moreover, metamorphic rocks can also transition into igneous or sedimentary rocks through further geological processes, illustrating the dynamic nature of the rock cycle.