Rocks and Minerals

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The rock cycle is very important to us because it explains the way the different types of rocks are formed on earth. The rocks currently visible on the Earth’s surface have moved through transition stages that transformed them from one form into another. The importance of the rock cycle lies in how it forms and recycles the various layers that make up the Earth. To do this, the cycle moves through three different stages that produce three different types of rock.

Igneous rock makes up the foundation on which the Earth’s continents sit. This type of rock is made as magma cools over time, crystalline structures begin to form. Volcanic eruptions send magma across the Earth’s surface as well as into underground layers. The magma that settles underground cools slower than what makes its way to the Earth’s surface. In effect, igneous rock can form on the surface or within the underground layers. Volcanic Rocks (also called extrusive igneous rocks) include all the products resulting from eruptions of lava (flows and fragmented debris called pyroclasts).Plutonic Rocks (also called intrusive igneous rocks) are those that have solidified below ground; plutonic comes from Pluto, the Greek god of the underworld. . Metamorphic rocks are created when other types of rocks are transformed due to great pressure and heat within the earth. The meaning of the term ‘metamorphic’, in fact, is ‘changed’. When igneous rocks, or sedimentary rocks, or even metamorphic rocks get buried very deep under the earth’s surface, a process that takes millions of years, they get changed into something else by the enormous pressure and heat inside the earth. The foliation or layering that occurs in many types of metamorphic rocks is because of the immense directional pressure they undergo deep within the earth, usually along the boundary of a converging plate tectonic. Gneiss: This metamorphic rock is classified as high grade, which means that...
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