GENERAL GEOLOGY

Detailed explanation-1: -Metamorphism, therefore occurs at temperatures and pressures higher than 200oC and 300 MPa. Rocks can be subjected to these higher temperatures and pressures as they are buried deeper in the Earth. Such burial usually takes place as a result of tectonic processes such as continental collisions or subduction.

Detailed explanation-2: -Regional metamorphism is caused by large geologic processes such as mountain-building. These rocks when exposed to the surface show the unbelievable pressure that cause the rocks to be bent and broken by the mountain building process. Regional metamorphism usually produces foliated rocks such as gneiss and schist.

Detailed explanation-3: -Regional metamorphism Such rocks cover large areas of the Earth’s crust and are therefore termed regional metamorphic rocks. They arise by the combined action of heat, burial pressure, differential stress, strain and fluids on pre-existing rocks.

Detailed explanation-4: -If metamorphic rocks are buried much deeper in the crust (Fig. 1.6), they melt and form igneous rocks.

Detailed explanation-5: -Metamorphic rock can originate not only as igneous and sedimentary rock but also other types of metamorphic rock. During contact metamorphism, broken down pieces of rock near the Earth’s surface is altered by magma. During regional metamorphism, rocks buried deep within the Earth are altered by magma chambers.