Do You Think Igneous Rock Can Become Magma Again? Why or Why Not? Formats Font Family Font Sizes

Transitions through geologic time amongst the iii master rock types: sedimentary, metamorphic, and igneous

This diamond is a mineral from within an igneous or metamorphic rock that formed at loftier temperature and pressure

The rock cycle is a basic concept in geology that describes transitions through geologic fourth dimension among the 3 principal rock types: sedimentary, metamorphic, and igneous. Each stone type is altered when information technology is forced out of its equilibrium conditions. For instance, an igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the h2o bike, rocks practise not remain in equilibrium and change as they come across new environments. The stone cycle explains how the three rock types are related to each other, and how processes modify from ane type to another over time. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle.

The rock wheel

Transition to igneous stone

When rocks are pushed deep nether the World's surface, they may melt into magma. If the atmospheric condition no longer exist for the magma to stay in its liquid state, it cools and solidifies into an igneous rock. A rock that cools within the Globe is called intrusive or plutonic and cools very slowly, producing a fibroid-grained texture such as the rock granite. As a result of volcanic activity, magma (which is chosen lava when it reaches Earth'southward surface) may cool very rapidly on the Earth'due south surface exposed to the temper and are called extrusive or volcanic rocks. These rocks are fine-grained and sometimes absurd and then apace that no crystals can form and event in a natural glass, such equally obsidian, even so the nearly common fine-grained rock would be known equally basalt. Whatever of the three main types of rocks (igneous, sedimentary, and metamorphic rocks) can cook into magma and cool into igneous rocks.

Secondary changes

Epigenetic modify (secondary processes occurring at low temperatures and low pressures) may exist arranged under a number of headings, each of which is typical of a group of rocks or rock-forming minerals, though ordinarily more than one of these alterations is in progress in the same rock. Silicification, the replacement of the minerals by crystalline or crypto-crystalline silica, is most common in felsic rocks, such as rhyolite, but is as well establish in serpentine, etc. Kaolinization is the decomposition of the feldspars, which are the most mutual minerals in igneous rocks, into kaolin (along with quartz and other dirt minerals); it is best shown by granites and syenites. Serpentinization is the alteration of olivine to serpentine (with magnetite); it is typical of peridotites, but occurs in most of the mafic rocks. In uralitization, secondary hornblende replaces augite; chloritization is the alteration of augite (biotite or hornblende) to chlorite, and is seen in many diabases, diorites and greenstones. Epidotization occurs also in rocks of this group, and consists in the evolution of epidote from biotite, hornblende, augite or plagioclase feldspar.^[one]

Transition to metamorphic stone

Rocks exposed to high temperatures and pressures can be changed physically or chemically to course a different rock, called metamorphic. Regional metamorphism refers to the effects on large masses of rocks over a wide surface area, typically associated with mountain building events within orogenic belts. These rocks usually exhibit singled-out bands of differing mineralogy and colors, called foliation. Another main blazon of metamorphism is caused when a body of rock comes into contact with an igneous intrusion that heats upward this surrounding country rock. This contact metamorphism results in a rock that is altered and re-crystallized by the farthermost oestrus of the magma and/or by the addition of fluids from the magma that add chemicals to the surrounding rock (metasomatism). Any pre-existing type of rock tin can be modified by the processes of metamorphism.

Transition to sedimentary rock

Rocks exposed to the temper are variably unstable and subject to the processes of weathering and erosion. Weathering and erosion intermission the original rock downward into smaller fragments and carry away dissolved material. This fragmented material accumulates and is buried by additional textile. While an private grain of sand is however a member of the class of rock it was formed from, a rock made up of such grains fused together is sedimentary. Sedimentary rocks tin can be formed from the lithification of these buried smaller fragments (clastic sedimentary rock), the accumulation and lithification of material generated by living organisms (biogenic sedimentary rock - fossils), or lithification of chemically precipitated textile from a mineral begetting solution due to evaporation (precipitate sedimentary rock). Clastic rocks can be formed from fragments broken autonomously from larger rocks of any type, due to processes such as erosion or from organic material, like constitute remains. Biogenic and precipitate rocks form from the deposition of minerals from chemicals dissolved from all other rock types.

Forces that drive the stone bicycle

Plate tectonics

In 1967, J. Tuzo Wilson published an article in Nature describing the repeated opening and closing of ocean basins, in particular focusing on the current Atlantic Ocean area. This concept, a part of the plate tectonics revolution, became known as the Wilson cycle. The Wilson bicycle has had profound effects on the modernistic interpretation of the rock bicycle as plate tectonics became recognized equally the driving forcefulness for the rock bike.

Spreading ridges

At the mid-ocean divergent boundaries new magma is produced by mantle upwelling and a shallow melting zone. This juvenile basaltic magma is an early on phase of the igneous portion of the cycle. As the tectonic plates on either side of the ridge move autonomously the new rock is carried abroad from the ridge, the interaction of heated circulating seawater through fractures starts the retrograde metamorphism of the new rock.

Subduction zones

The new basaltic oceanic crust eventually meets a subduction zone every bit it moves abroad from the spreading ridge. As this crust is pulled dorsum into the mantle, the increasing pressure and temperature weather cause a restructuring of the mineralogy of the rock, this metamorphism alters the rock to class eclogite. Every bit the slab of basaltic crust and some included sediments are dragged deeper, water and other more volatile materials are driven off and rising into the overlying wedge of rock above the subduction zone, which is at a lower force per unit area. The lower force per unit area, high temperature, and now volatile rich material in this wedge melts and the resulting buoyant magma rises through the overlying rock to produce island arc or continental margin volcanism. This volcanism includes more silicic lavas the further from the edge of the island arc or continental margin, indicating a deeper source and a more differentiated magma.

At times some of the metamorphosed downgoing slab may be thrust upwardly or obducted onto the continental margin. These blocks of mantle peridotite and the metamorphic eclogites are exposed as ophiolite complexes.

The newly erupted volcanic cloth is subject field to rapid erosion depending on the climate weather condition. These sediments accumulate inside the basins on either side of an island arc. As the sediments get more deeply buried lithification begins and sedimentary rock results.

Continental standoff

On the endmost phase of the classic Wilson bike, ii continental or smaller terranes meet at a convergent zone. As the two masses of continental crust run into, neither tin be subducted every bit they are both low density silicic stone. Every bit the ii masses meet, tremendous compressional forces distort and modify the rocks involved. The result is regional metamorphism within the interior of the ensuing orogeny or mount building event. As the two masses are compressed, folded and faulted into a mountain range by the continental collision the whole suite of pre-existing igneous, volcanic, sedimentary and earlier metamorphic rock units are subjected to this new metamorphic issue.

Accelerated erosion

The high mount ranges produced by continental collisions are immediately subjected to the forces of erosion. Erosion wears downward the mountains and massive piles of sediment are developed in adjacent sea margins, shallow seas, and equally continental deposits. As these sediment piles are buried deeper they become lithified into sedimentary stone. The metamorphic, igneous, and sedimentary rocks of the mountains become the new piles of sediments in the adjoining basins and eventually go sedimentary rock.

An evolving procedure

The plate tectonics stone cycle is an evolutionary process. Magma generation, both in the spreading ridge environment and inside the wedge above a subduction zone, favors the eruption of the more than silicic and volatile rich fraction of the crustal or upper drape material. This lower density material tends to stay within the chaff and not be subducted dorsum into the drape. The magmatic aspects of plate tectonics tends to gradual segregation inside or between the mantle and crust. As magma forms, the initial melt is composed of the more silicic phases that have a lower melting indicate. This leads to partial melting and further segregation of the lithosphere. In improver the silicic continental crust is relatively buoyant and is non normally subducted back into the mantle. So over time the continental masses grow larger and larger.

The part of water

The presence of abundant h2o on Earth is of peachy importance for the rock bicycle. Virtually obvious perhaps are the water driven processes of weathering and erosion. Water in the form of atmospheric precipitation and acidic soil h2o and groundwater is quite effective at dissolving minerals and rocks, particularly those igneous and metamorphic rocks and marine sedimentary rocks that are unstable nether near surface and atmospheric atmospheric condition. The h2o carries away the ions dissolved in solution and the broken-downwards fragments that are the products of weathering. Running water carries vast amounts of sediment in rivers back to the sea and inland basins. The accumulated and buried sediments are converted back into rock.

A less obvious role of water is in the metamorphism processes that occur in fresh seafloor volcanic rocks as seawater, sometimes heated, flows through the fractures and crevices in the rock. All of these processes, illustrated by serpentinization, are an important part of the destruction of volcanic rock.

The role of h2o and other volatiles in the melting of existing crustal rock in the wedge above a subduction zone is a near of import office of the cycle. Along with h2o, the presence of carbon dioxide and other carbon compounds from arable marine limestone inside the sediments atop the downward going slab is another source of melt inducing volatiles. This involves the carbon bike as a function of the overall stone bike.

Run across also

• Migmatite – Mixture of metamorphic stone and igneous rock

References

1. ^ One or more of the preceding sentences incorporates text from a publication at present in the public domain:Flett, John Smith (1911). "Petrology". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 21 (11th ed.). Cambridge University Press. p. 331.

• Blatt, Harvey & Robert J. Tracy (1996). Petrology; Igneous, Sedimentary, and Metamorphic, 2nd Ed. W. H. Freeman. ISBN0-7167-2438-3.
• Fichter, Lynn S., (2000), The Wilson Bicycle and a Plate Tectonic Rock Cycle, James Madison University, Department of Geology and Ecology Scientific discipline. Retrieved 18 Aug. 2005.
• Plummer, Charles; McGeary, David; Carlson, Diane (2005). Concrete Geology. Mc Graw Hill. ISBN0-07-293353-4.

External links

• The 6 Central Concepts about the Earth'south Geology - NASA
• Wilson cycle - a detailed Plate Tectonics rock cycle
• Modelling the rock wheel with STELLA
• Wilson cycle
• A round Wilson cycle?

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Source: https://en.wikipedia.org/wiki/Rock_cycle