Earth science Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres ...

, a geochemical cycle is the pathway that

chemical elements A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...

take in the surface and crust of the Earth. The term "

geochemical Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...

" tells us that geological and chemical factors are all included. The migration of heated and compressed chemical elements and compounds such as

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

, and general alkali metals through the means of

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

and

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...

is known in the geological world as geochemical cycles. The geochemical cycle encompasses the natural separation and concentration of elements and heat-assisted recombination processes. Changes may not be apparent over a short term, such as with

biogeochemical cycles A biogeochemical cycle (or more generally a cycle of matter) is the pathway by which a chemical substance cycles (is turned over or moves through) the biotic and the abiotic compartments of Earth. The biotic compartment is the biosphere and the ...

, but over a long term changes of great magnitude occur, including the evolution of continents and oceans.

Differentiating biogeochemical cycles

Some may use the terms

biogeochemical cycle A biogeochemical cycle (or more generally a cycle of matter) is the pathway by which a chemical substance cycles (is turned over or moves through) the biotic and the abiotic compartments of Earth. The biotic compartment is the biosphere and the ...

and geochemical cycle interchangeably because both cycles deal with Earth's reservoirs. However, a biogeochemical cycle refers to the chemical interactions in surface reservoirs such as the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

hydrosphere The hydrosphere () is the combined mass of water found on, under, and above the surface of a planet, minor planet, or natural satellite. Although Earth's hydrosphere has been around for about 4 billion years, it continues to change in shape. This ...

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust (geology), crust and the portion of the upper mantle (geology), mantle that behaves elastically on time sca ...

, and biosphere whereas a geochemical cycle refers to the chemical interactions that exist in crustal and sub crustal reservoirs such as the deep earth and

Earth system

The

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

, as a system, is open to radiation from the sun and space, but is practically closed with regard to

matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...

. As all closed systems, it follows the law of conservation of mass which states that matter cannot be created nor destroyed, thus, the matter, although transformed and migrated, remains the same as when the

was formed. The

system contains seven different

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

s that are separated into surface reservoirs, which include

, biosphere, pedosphere, and

and the isolated reservoirs that include deep Earth and

outer space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...

. Geochemical cycles are concerned with the interactions between deep earth which consists of Earth's

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

and core, and the

which consists of the Earth's crust.

Pathways

Flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ph ...

in geochemical cycles is the movement of material between the deep Earth and the surface reservoirs. This occurs through two different processes:

and

tectonic plates Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

Subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

is the process that takes place at

convergent boundaries A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

by which one

tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

moves under another tectonic plate and sinks into the

as the plates converge. This leads to the sinking of one plate into the mantle which creates a broad range of geochemical transformations or cycling.

Volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...

is the process that takes place at divergent boundaries by which one

separates from another creating a rift in which molten rock (

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

) erupts onto the surface of the

. This molten rock

then cools and crystallizes, forming igneous rocks. If crystallization occurs at the Earth's surface, extrusive

igneous rocks Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...

are formed; if crystallization occurs within the Earth's

, intrusive igneous rocks are formed which can then be brought to Earth's surface by denudation

Important cycles

Categories and examples of geochemical cycles: File:Diagram of the Water Cycle.jpg,

Deep water cycle The deep water cycle, or geologic water cycle, involves exchange of water with the mantle, with water carried down by subducting oceanic plates and returning through volcanic activity, distinct from the water cycle process that occurs above and ...

File:Reservoirs and fluxes of carbon in deep Earth.png,

Deep carbon cycle The deep carbon cycle is geochemical cycle (movement) of carbon through the Earth's mantle and core. It forms part of the carbon cycle and is intimately connected to the movement of carbon in the Earth's surface and atmosphere. By returning carb ...

(is part of

carbon cycle The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and Earth's atmosphere, atmosphere of the Earth. Carbon is the main component of biological compounds as well as ...

) File:Iron cycle7.png,

Iron cycle The iron cycle (Fe) is the biogeochemical cycle of iron through the atmosphere, hydrosphere, biosphere and lithosphere. While Fe is highly abundant in the Earth's crust, it is less common in oxygenated surface waters. Iron is a key micronutrient i ...

File:Carbonate-Silicate Cycle (Carbon Cycle focus).jpg,

Carbonate–silicate cycle The carbonate–silicate geochemical cycle, also known as the inorganic carbon cycle, describes the long-term transformation of silicate rocks to Carbonate rock, carbonate rocks by weathering and sedimentation, and the transformation of carbonate ...

File:Phosphorus cycle.png, Phosphorus cycle File:Sulfur cycle - English.jpg,

Sulfur cycle The sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element ( CHNOPS), being a const ...

File:Rockcycle.jpg, Rock cycle File:PhysicalMercuryCycle.png,

Mercury cycle The mercury cycle is a biogeochemical cycle influenced by natural and anthropogenic processes that transform mercury through multiple chemical forms and environments. Mercury is present in the Earth's crust and in various forms on the Earth� ...

References

{{reflist Geochemistry

Differentiating biogeochemical cycles

Earth system

Pathways

Important cycles

See also

References