Metamorphic Rocks

Metamorphic rocks (or metamorphic rocks) is one of the major groups of rocks that are the result of transformation or alteration of a rock type that has been there before, protolith, by a process called metamorphism, which means "change form". Protolith is subjected to heat (greater than 150 ° Celsius) and extreme pressure will experience physical changes and / or chemical change. Protolith may be sedimentary rock, igneous, or metamorphic rocks are older. Some examples are gneis metamorphic rock, slate, marble, and skist.
Metamorphic rock up a large part of the Earth's crust and are classified by texture and composition of chemical and mineral (metamorphic facies) They are formed deep below the surface of the earth by the great sharpness of the rocks above and high pressures and temperatures. They also formed by the intrusion of molten rock, called magma, into solid rock and is formed mainly on the contact between magma and high-temperature rocks.
Research metamorphic rocks (now exposed at the earth's surface due to erosion and removal) gives us very valuable information about temperatures and pressures that occur deep within the earth's surface.
Metamorphic rocks can be divided into the following.
a. Contact metamorphic rocks
Rocks that experienced metamorfose as a result of very high temperatures (as a result of magma activity). The existence of a very high temperature leads to changes in shape and color of rock. For example limestone (limestone) into marble.
b. Dinamo metamorphic rocks
Rocks that experienced metamorfose as a result of high pressure (derived from endogenous force) in a long time. For example mudstone (mud stone) menjzdi slate (slate). These rocks are often found in the area of ​​fault or fold.
c. Contact metamorphic rocks Pneumatolistis
Rocks that experienced metamorfose as a result of the influence of the gases that exist in the magma. For example quartz with fluorium gas turns into topaz.