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A mantle is a layer inside a
planetary body A planet is an astronomical body orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet around a star or a natural satellite around a planet. Normally, orbit r ...
bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by
density The density (more precisely, the volumetric mass density; also known as specific mass), of a substance is its mass per unit volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter Rho (letter), rho), although the L ...
. All terrestrial planets (including
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. About 29% of Earth's surface is land consisting of continent A continent is one of several large landmasses. Generally identified by con ...
), a number of
asteroids An asteroid is a minor planet A minor planet is an astronomical object in direct orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet around a star or a ...
, and some planetary
moons A natural satellite, or moon, is, in the most common usage, an astronomical body that orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet around a star or ...
have mantles.


Earth's mantle

The
Earth's mantle Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 1024 kg and thus makes up 67% of the mass of Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly sol ...
is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 1024 kg is 67% the mass of the Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly solid but in geological time it behaves as a
viscous The viscosity of a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), phase of matter and include liquids, Gas, ...
fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), phase of matter and include liquids, Gas, gases and Plasma (physics), pl ...
. Partial melting of the mantle at
mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics File:Earth cutaway schematic-en.svg, upright=1.35, Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale) Plate ...
s produces oceanic crust, and partial melting of the mantle at subduction zones produces continental crust.


Other planetary mantles

Mercury (planet), Mercury has a silicate mantle approximately 490 km thick, constituting only 28% of its mass. Venus, Venus's silicate mantle is approximately 2800 km thick, constituting around 70% of its mass. Mars, Mars's silicate mantle is approximately 1600 km thick, constituting ~74–88% of its mass, and may be represented by Martian meteorite, chassignite meteorites.


Moons with mantles

Jupiter, Jupiter's moons Io (moon), Io, Europa (moon), Europa, and Ganymede (moon), Ganymede have silicate mantles; Io's ~1100 km silicate mantle is overlain by a volcanic crust, Ganymede's ~1315 km thick silicate mantle is overlain by ~835 km of ice, and Europa's ~1165 km silicate mantle is overlain by ~85 km of ice and possibly liquid water. The silicate mantle of the Moon, Earth's moon is approximately 1300–1400 km thick, and is the source of Moon rock, mare basalts. The lunar mantle might possibly be exposed in the South Pole–Aitken basin, South Pole-Aitken basin or the Mare Crisium, Crisium basin. The lunar mantle contains a seismic discontinuity at ~500 km depth, most likely related to a change in composition. Titan (moon), Titan and Triton (moon), Triton each have a mantle made of ice or other Ice#Other ices, solid volatile substances.


Asteroids with mantles

Some of the largest
asteroids An asteroid is a minor planet A minor planet is an astronomical object in direct orbit In physics, an orbit is the gravitationally curved trajectory of an physical body, object, such as the trajectory of a planet around a star or a ...
have mantles; for example, 4 Vesta, Vesta has a silicate mantle similar in composition to diogenite meteorites.


See also

* Earth's internal heat budget * Lehmann discontinuity * Lithosphere#Mantle xenoliths, Mantle xenoliths * Mantle convection * Mesosphere (mantle) * Numerical modeling (geology) * Primitive mantle


References


Further reading

* Don L. Anderson
''Theory of the Earth''
Blackwell (1989), is a textbook dealing with the Earth's interior and is now available on the web. Retrieved 2007-12-23. * * Nixon, Peter H. (1987). Mantle xenoliths: J. Wiley & Sons, 844p., (). * Donald L. Turcotte and Gerald Schubert, Geodynamics, Cambridge University Press, Third Edition (2014), (Hardback) (Paperback)


External links


The Biggest Dig: Japan builds a ship to drill to the earth's mantle
– Scientific American (September 2005)
Information on the Mohole Project
{{DEFAULTSORT:Mantle (Geology) Structure of the Earth Planetary geology