Answer :
In the context of where mid-grade metamorphic rocks are commonly formed, it is important to understand the processes involved in their formation.
Mid-grade metamorphic rocks are typically formed in the rocks that are in contact with the magma chamber. When magma (molten rock beneath the Earth's surface) intrudes into the surrounding rock, the heat and pressure generated during this process can lead to the metamorphism of the rocks in contact with the magma chamber. This interaction causes changes in the mineral composition and texture of the rocks, resulting in the formation of mid-grade metamorphic rocks.
To further clarify, mid-grade metamorphic rocks are not formed inside the magma chamber itself, as the extreme heat and pressure inside the magma chamber are more conducive to the formation of igneous rocks rather than metamorphic rocks. Similarly, while metamorphic rocks can also form in mountainous regions due to the intense pressure and temperature associated with tectonic processes, mid-grade metamorphic rocks specifically have a higher likelihood of forming in rocks that come into contact with the magma chamber.
Therefore, the most common area where mid-grade metamorphic rocks are formed is in the rocks that are in contact with the magma chamber due to the heat and pressure generated by the intrusion of magma into the surrounding rock layers.
