A mantle is a layer inside a
planetary body
A planetary-mass object (PMO), planemo, or planetary body is by geophysical definition of planet, geophysical definition of celestial objects any celestial object massive enough to achieve hydrostatic equilibrium (to be rounded under its own gra ...
bounded below by a
core
Core or cores may refer to:
Science and technology
* Core (anatomy), everything except the appendages
* Core (manufacturing), used in casting and molding
* Core (optical fiber), the signal-carrying portion of an optical fiber
* Core, the centra ...
and above by a
crust. Mantles are made of
rock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wales ...
or
ice
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...
s, 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
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...
. All
terrestrial planets
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Ven ...
(including
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 ...
), a number of
asteroids
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
, and some planetary
moons
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'' ...
have mantles.
Earth's mantle
![Earth poster](https://upload.wikimedia.org/wikipedia/commons/0/07/Earth_poster.svg)
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
Earth's outer core is a fluid layer about thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. The outer core begins approximately beneath Earth's surface at the core-mantle boundary and e ...
. Its mass of 4.01 × 10
24 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
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...
it behaves as a
viscous
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inter ...
fluid
In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...
. Partial melting of the mantle at
mid-ocean ridge
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diverge ...
s produces
oceanic crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumu ...
, and
partial melting
Partial melting occurs when only a portion of a solid is melted. For mixed substances, such as a rock containing several different minerals or a mineral that displays solid solution, this melt can be different from the bulk composition of the soli ...
of the mantle at
subduction zones produces
continental crust
Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...
.
Other planetary mantles
Mercury
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Merc ...
has a silicate mantle approximately thick, constituting only 28% of its mass.
Venus's silicate mantle is approximately thick, constituting around 70% of its mass.
Mars's silicate mantle is approximately thick, constituting ~74–88% of its mass,
and may be represented by
chassignite
A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a percen ...
meteorites.
Moons with mantles
Jupiter's moons
Io,
Europa
Europa may refer to:
Places
* Europe
* Europa (Roman province), a province within the Diocese of Thrace
* Europa (Seville Metro), Seville, Spain; a station on the Seville Metro
* Europa City, Paris, France; a planned development
* Europa Cliff ...
, and
Ganymede have silicate mantles; Io's ~ silicate mantle is overlain by a volcanic crust, Ganymede's ~ thick silicate mantle is overlain by ~ of ice, and Europa's ~ km silicate mantle is overlain by ~ of ice and possibly liquid water.
The silicate mantle of the
Earth's moon is approximately 1300–1400 km thick, and is the source of
mare basalts.
The lunar mantle might be exposed in the
South Pole-Aitken basin
South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþaz' ...
or the
Crisium basin
Mare Crisium (Latin ''crisium'', the "Sea of Crises") is a lunar mare located in the Moon's Crisium basin, just northeast of Mare Tranquillitatis. The basin is of the Pre-Imbrian period, 4.55 to 3.85 billion years ago.
Characteristics
Mare Cri ...
.
The lunar mantle contains a seismic discontinuity at ~ depth, most likely related to a change in composition.
Titan and
Triton
Triton commonly refers to:
* Triton (mythology), a Greek god
* Triton (moon), a satellite of Neptune
Triton may also refer to:
Biology
* Triton cockatoo, a parrot
* Triton (gastropod), a group of sea snails
* ''Triton'', a synonym of ''Triturus' ...
each have a mantle made of
ice
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...
or other
solid volatile substances.
Asteroids with mantles
Some of the largest
asteroids
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
have mantles; for example,
Vesta has a silicate mantle similar in composition to
diogenite
Diogenites are a group of the HED meteorite clan, a type of achondritic stony meteorites.
Origin and composition
Diogenites are currently believed to originate from deep within the crust of the asteroid 4 Vesta, and as such are part of the HED m ...
meteorites.
See also
*
Earth's internal heat budget
Earth's internal heat budget is fundamental to the thermal history of the Earth. The flow of heat from Earth's interior to the surface is estimated at 47±2 terawatts (TW)Davies, J. H., & Davies, D. R. (2010). Earth's surface heat flux. Solid ...
*
Lehmann discontinuity
__NOTOC__
The Lehmann discontinuity is an abrupt increase of ''P''-wave and ''S''-wave velocities at the depth of , discovered by seismologist Inge Lehmann. The thickness is 220 km . It appears beneath continents, but not usually beneath ocea ...
*
Mantle xenoliths
*
Mantle convection
Mantle convection is the very slow creeping motion of Earth's solid silicate mantle as convection currents carrying heat from the interior to the planet's surface.
The Earth's surface lithosphere rides atop the asthenosphere and the two form ...
*
Mesosphere (mantle)
The lower mantle, historically also known as the mesosphere, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below Earth's surface; between the transition zone and the outer core. The preliminary ...
*
Numerical modeling (geology)
*
Primitive mantle
In geochemistry, the primitive mantle (also known as the ''bulk silicate Earth'') is the chemical composition of the Earth's mantle during the developmental stage between core-mantle differentiation and the formation of early continental crust. ...
References
Further reading
*
Don L. Anderson
Don Lynn Anderson (March 5, 1933 – December 2, 2014) was an American geophysicist who made significant contributions to the understanding of the origin, evolution, structure, and composition of Earth and other planets. An expert in numer ...
''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
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press
A university press is an academic publishing hou ...
, 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