How is Metamorphic Rock Formed

Are you wondering how a metamorphic rock is formed? There is a simple answer. Before that, the surface of the earth is covered with mainly three types of rocks namely igneous, sedimentary, and metamorphic rocks. Metamorphic rocks are so called because they are created from the metamorphism of pre-existing rocks. However, many people find it hard to understand and visualize the formation of these very important rocks that are found in all parts of the world. This article attempts to explain how a metamorphic rock is formed in easy to understand ways.

Metamorphic Rock Facts

Metamorphic rocks are formed from rocks that are pre-existing

Metamorphic rocks are pre-existing rocks on the surface of the earth that change in composition and density over a long period under the influence of pressure and heat. They could be either igneous or sedimentary rocks. They could even be formed from pre-existing metamorphic rocks. Different rocks have different compositions as they are, usually, made up of one or more minerals. Rocks that get morphed into another type are called metamorphic rocks. Some metamorphic rocks may have the same composition as other sedimentary or igneous rocks, but rocks are mainly classified on the basis of the process of their formation.

How is metamorphic rock formed

Sedimentary and igneous rocks lying deep within the surface of the earth are subjected to extreme heat and pressure.

Processes involved in the formation of metamorphic rocks

There are two processes of formation of metamorphic rocks that are as follows.

Contact metamorphism

This is a process that starts when hot magma finds its way inside an existing rock. Heat of the molten magma bakes the surrounding rocks and they develop fissures that allow passage of this hot liquid inside them. Change takes place in the composition of these rocks and they become metamorphic rocks. This is a change that is local in nature and the extent of changes taking place is also very small. This is why contact metamorphism is referred to as low-grade metamorphism. Marble is a fine example of contact metamorphism as it changes from limestone when subjected to extreme heat by magma.

Regional metamorphism

These are rocks that are formed over a long period in pre-existing large masses of rocks. This is a high-grade metamorphism that is associated with the process of mountain building. The rocks that are at the bottom are subjected to extreme pressure from the weight of the overlying rocks. Their composition changes and they become compact and denser than before. Pressure causes a change in the crystals of the rocks and they get arranged into layers. Slate is a great example of a metamorphic rock formed with the help of regional metamorphism. It is used to make roof tiles as its layers can be easily separated to make tile sheets. Friction and movement of tectonic plates of the earth also leads to the creation of metamorphic rocks.

Some examples of metamorphic rocks

• Granulate is a metamorphic rock that results when metamorphism of basalt (igneous rock) takes place.

• Mudstone is a sedimentary rock that is metamorphosed into slate.

• Sandstone is a sedimentary rock that gives way to metamorphic rock quartzite. 

Image Courtesy:

  1. image by  ()

About the Author: admin

Leave a Comment

Related pages

thermosetting polymer listwhere does transcription occur in eukaryotesthe difference between evaporation and condensationpossessive adjective possessive pronounassertive meaning in hindicharacteristics of surrealismdifference of brandy and whiskyzoospores in fungireactance vs resistancehow to spot fake levis 501medusa body formlenses concave and convexwhat is a simile metaphordifference between cilantro and corianderspeech elocutionprohibitive meaning in hindidifferent types of calipersnegative and affirmative sentenceschloroplast structure functionidioms and phraseabbreviation and acronym examplesinner vs outer planetsrmr vs bmraddendum vs appendixbiennially definitionvernier caliper and micrometer caliperdifference between pronunciation and annunciationaccomodation vs assimilationlife cycle of pteridophytawhat is the difference between schizoaffective disorder and schizophreniamodulus of rigidity formulacellulose versus starchwhat are dizygotic twinssimilarities between command and market economywhat is the difference between a shark and a fishcollenchyma functionthermal insulators and conductorsshiba sheddingtofu or paneerhomophone and homographtwo centrosomes are arranged at opposite poles of the cellkaryokinesis in mitosiswhats a serfvillage life better than city life essayis glucose a ketosefuchsia and magenta differencedifference between starch and glycogenserf medievaldifferences between bacteria and virusesbryophyte characteristicsrestrain definenitrite lewis structuredifferentiate between unicellular and multicellularcoenzymes and prosthetic groupsdifference between cytoplasm and protoplasmdifference between opera and oratoriodelhi to kullu manali trainparallelism definition literaturedifference between saturated and unsaturated fatty acidis parsley and coriander sameprotostomes deuterostomeswhat is figurative and literal languageapplication of angle of reposechamfered definitiondifference between hair smoothening and hair straighteningwhat is primary and secondary successionpronoun vs nounphotoelectric effect and compton effecthusky vs alaskan malamuterhythm rhymemetric vs imperial tondifference between porifera and coelenteratadifference between fermentation and aerobic respirationcilia or flagelladifference between md and phd in medicineconcrete noun with exampleswhat are macronutrients and micronutrients