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What rock is formed when magma cools at the Earth's surface?

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Quick Answer

The specific type of rock that forms when magma cools at the Earth's surface is extrusive igneous rock. Igneous rock forms when magma cools, but where the magma cools determines the type of igneous rock that forms. Igneous rock gets its name from the Greek word for fire and is so called due to the extremely hot liquid from which the rocks originate.

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What rock is formed when magma cools at the Earth's surface?
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Full Answer

When magma cools at the surface, it cools rapidly and does not have time to form very large crystals. Basalt, found on the ocean floor, is an example of an extrusive igneous rock. On the other hand, magma that cools slowly beneath the Earth's surface forms rocks that contain large crystals. Geologists refer to these as intrusive igneous rocks; granite is an example of an intrusive igneous rock.

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Related Questions

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    How many different types of rock are in the Earth's surface?

    A:

    There are three types of rock on the Earth's surface: metamorphic, sedimentary and igneous. Metamorphic rocks are rocks that have changed from one form to the other. Sedimentary rocks are formed from compressed layers of organic and inorganic matter, while igneous rocks are formed from cooled and hardened magma.

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    How is granite formed?

    A:

    Granite is an igneous rock that forms when a pocket of magma rises into the upper levels of the Earth's crust and slowly cools. Cooling slowly gives granite, which is composed mainly of feldspar and quartz, enough time to develop large crystals that make the stone very hard and strong. Some granite, known as gneiss, can form from sedimentary rock that has gone through a long metamorphosis.

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    A:

    Obsidian is a type of igneous rock created when felsic magma cools and hardens before it can form a crystalline structure. It is characterized by its smooth texture and extremely sharp edges.

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    How does the Earth's crust recycle itself?

    A:

    The Earth's crust recycles itself through subduction of crustal material into the mantle and upwelling of magma from the mantle. These processes are described by plate tectonics, a commonly accepted theory that explains the large-scale movements of the Earth's lithosphere.

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