Rocks may be speckled or solid-colored, bumpy or smooth, thick or filled through holes. A rock"s look has actually a lot to do with that mineral make-up. But, just as important is how the absent formed. There room three types of rock formations. One kind forms once melted rock cools and also hardens. A second type consists of layers of little particles. The 3rd rock form forms under extreme heat and also pressure.

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How room They Formed?
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Granite creates when melted absent cools and also hardens.
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Layers of small particles produced this rock frequently known together coal.
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Intense heat and also pressure resulted in this rock, referred to as marble, come form.

Rock created by Cooling and Hardening

One kind of rock it s okay its start deep in the planet in large underground pockets. There, the rock is so hot that the melts. This molten rock, dubbed magma, is choose a soup of different minerals and elements.

Because magma is less thick (and lighter in weight) than the hard rock approximately it, it flows upward. Together it rises to the surface, Earth"s temperature it s okay lower. The magma cools and also hardens. The result is igneous rock.

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Magma"s temperature is 1400° come 2300 °F (760° come 1300 °C).

Igneous Rock listed below Ground

Magma often flows up v deep crack in the solid rock currently there. Sometimes it spreads out in between layers of larger rock. Occasionally it cuts across different layers, pushing against the rock together it moves. This magma eventually settles listed below ground come cool and also harden.

Underground, or intrusive, igneous rock forms an extremely slowly. It cools and hardens over tens of thousands of years. During this period, the rock"s minerals have a lengthy time to kind crystals, or crystallize. Regularly these crystals grow large enough to see.

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Granite is an instance of an intrusive igneous rock.

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This vast granite absent in Yosemite national Park rises an ext than 4,737 feet (1,444 meters) above the valley floor.

Igneous Rock over Ground

Hot magma also rises to the Earth"s surface. It often pushes up v long, open pipelines in hard rock. This cone-like mountains, dubbed volcanoes, construct up in size as an ext and much more magma operation out.

When magma meets the air and hardens, it creates extrusive igneous rock. That hardens very quickly. In various other words, every one of its mineral crystallize rapidly. Together a result, lock are an extremely small.

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LAVA FLOW

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Lava is another name because that magma that flows from volcano vents. Ash, cinders, and also gas likewise spew indigenous volcanoes


Rock created From Particles

Hardening magma is only one method that absent forms. A second form of rock creates from class of tiny particles, referred to as sediments. many sediments consist of small bits that rock. The loosened fragments come native larger, enlarge rocks.

Although solid rocks may seem never-changing, small rock pieces come off every the time. Occasionally rain loosens the surface of a rock. Sometimes water the freezes, then thaws, cracks open rocks and also loosens particles. The tiny fragments may loss down slopes and also settle. To run water and also wind may additionally carry corpuscle away. This process, known as weathering, take away place everywhere on Earth.

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Over numerous years, rivers can create canyons by eroding layer upon layer that rock.

These particles might be carried great distances. Lock may end up in a sea, a lakebed, or also on dried land. There, the sediments work out layer after layer.

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Everyday, the Mississippi river deposits thousands of loads of sediments as soon as it reaches the Gulf of Mexico.

Other Sediments

Sediments additionally come from various other sources, such together organic matter. In seawater, numerous tiny shells and skeletons may kind layers top top the bottom. In swamps, decaying plants slowly build up.

Certain minerals liquified in a body of water can form sediments, too. The process starts as the water slowly evaporates. End time, less and also less water stays to mix through the minerals. The overabundance minerals start grouping together to type crystals. These crystals slowly build up.

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Evaporation resulted in Gypsum favor this to crystallize in large, thick mineral beds.

Layers Squeezed Together

Whatever the sediment, the deposits kind thousands upon countless layers. As new layers settle on top, lock bury reduced layers deeper down in the earth. The load of the top layers squeezes the lower layers together. Moisture in the deepest great causes certain minerals to grow. Together they do, they cement every the sediments together. The result is sedimentary rock. The procedure takes thousands of thousands of years.

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The tide is a sandstone development on the slopes of Arizona"s Coyote Buttes.


Sedimentary absent from absent fragments:

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sandstone (sand)

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shale (clay and also mud)

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conglomerate sedimentary absent (mix the pebbles with mud or sand)

Sedimentary absent from essential matter:

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limestone (shells and also bones)

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coal (fossilized remains of swamp plants)

Sedimentary absent from liquified minerals:

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halite (edible “rock salt”


Rock developed By Heat and Pressure

A third form of rock develops when heat and/or pressure adjust old, heavy rock. This wake up far listed below Earth"s surface. There, extreme problems may reason a rock"s mineral to break apart and type new crystals. Or, miscellaneous minerals in the rock might come with each other to form new minerals. Metamorphic rock is the result of this process.

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Sometimes gases are current when metamorphic absent forms. This gases might add new elements to incorporate with the rock"s minerals. Their interaction can create new minerals.

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Often huge masses of deeply hidden rock change into metamorphic rock. But little areas have the right to change, too. This happens when flowing magma touch the hard rock approximately it. The extreme heat causes the old rock"s mineral to re-crystallize.

Buried RockMetamorphic Rock
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limestone
changes come …
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marble
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shale
changes to …
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slate
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slate
changes to …
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schist
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granite
changes to …
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gneiss