Mantle (geology)

A mantle is a layer inside a planetary body 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. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles.

Earth's mantle

The internal structure of Earth

The Earth's mantle 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.[1] It has a thickness of 2,900 kilometres (1,800 mi)[1] making up about 84% of Earth's volume. It is predominantly solid but in geological time it behaves as a viscous fluid. Partial melting of the mantle at mid-ocean ridges produces oceanic crust, and partial melting of the mantle at subduction zones produces continental crust.[2]

Other planetary mantles

Mercury has a silicate mantle approximately 490 km thick, constituting only 28% of its mass.[1] Venus's silicate mantle is approximately 2800 km thick, constituting around 70% of its mass.[1] Mars's silicate mantle is approximately 1600 km thick, constituting ~74–88% of its mass,[1] and may be represented by chassignite meteorites.[3]

Moons with mantles

Jupiter's moons Io, Europa, and 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.[1]

The silicate mantle of the Earth's moon is approximately 1300–1400 km thick, and is the source of mare basalts.[4] The lunar mantle might possibly be exposed in the South Pole-Aitken basin or the Crisium basin.[4] The lunar mantle contains a seismic discontinuity at ~500 km depth, most likely related to a change in composition.[4]

Titan and Triton each have a mantle made of ice or other solid volatile substances.[5][6]

Asteroids with mantles

Some of the largest asteroids have mantles;[7] for example, Vesta has a silicate mantle similar in composition to diogenite meteorites.[8]

See also

  • Earth's internal heat budget
  • Lehmann discontinuity
  • Mantle xenoliths
  • Mantle convection
  • Mesosphere (mantle)
  • Numerical modeling (geology)
  • Primitive mantle

References

  1. ^ a b c d e f Katharina., Lodders (1998). The planetary scientist's companion. Fegley, Bruce. New York: Oxford University Press. ISBN 978-1423759836. OCLC 65171709.
  2. ^ "What is the Earth's Mantle Made Of? – Universe Today". Universe Today. 2016-03-26. Retrieved 2018-11-24.
  3. ^ Swindle, T. D. (2002-01-01). "Martian Noble Gases". Reviews in Mineralogy and Geochemistry. 47 (1): 171–190. Bibcode:2002RvMG...47..171S. doi:10.2138/rmg.2002.47.6. ISSN 1529-6466.
  4. ^ a b c Wieczorek, M. A. (2006-01-01). "The Constitution and Structure of the Lunar Interior". Reviews in Mineralogy and Geochemistry. 60 (1): 221–364. Bibcode:2006RvMG...60..221W. doi:10.2138/rmg.2006.60.3. ISSN 1529-6466.
  5. ^ "Layers of Titan". NASA. 23 February 2012. Archived from the original on 14 September 2015. Retrieved 7 October 2015.
  6. ^ "Triton: In Depth". NASA. Archived from the original on 17 November 2015. Retrieved 16 October 2015.
  7. ^ "Griffith Observatory – Pieces of the Sky – Meteorite Histories". www.griffithobservatory.org. Retrieved 2018-11-24.
  8. ^ Reddy, Vishnu; Nathues, Andreas; Gaffey, Michael J. (2011-03-01). "First fragment of Asteroid 4 Vesta's mantle detected". Icarus. 212 (1): 175–179. Bibcode:2011Icar..212..175R. doi:10.1016/j.icarus.2010.11.032. ISSN 0019-1035.

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.
  • Jeanloz, Raymond (2000). "Mantle of the Earth". In Haraldur Sigurdsson; Bruce Houghton; Hazel Rymer; John Stix; Steve McNutt (eds.). Encyclopedia of Volcanoes. San Diego: Academic Press. pp. 41–54. ISBN 978-0-12-643140-7.
  • Nixon, Peter H. (1987). Mantle xenoliths: J. Wiley & Sons, 844p., (ISBN 0-471-91209-3).
  • Donald L. Turcotte and Gerald Schubert, Geodynamics, Cambridge University Press, Third Edition (2014),ISBN 978-1-107-00653-9 (Hardback)ISBN 978-0-521-18623-0 (Paperback)

External links

Media files used on this page

WikiProject Geology.svg
Author/Creator: unknown, Licence: CC BY-SA 2.5
The Earth seen from Apollo 17 with transparent background.png
"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972 by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,000 kilometers (18,000 statute miles). It shows Africa, Antarctica, and the Arabian Peninsula.
Crab Nebula.jpg
This is a mosaic image, one of the largest ever taken by NASA's Hubble Space Telescope, of the Crab Nebula, a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers recorded this violent event in 1054 CE, as did, almost certainly, Native Americans.

The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation. A neutron star is the crushed ultra-dense core of the exploded star.

The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. When viewed by Hubble, as well as by large ground-based telescopes such as the European Southern Observatory's Very Large Telescope, the Crab Nebula takes on a more detailed appearance that yields clues into the spectacular demise of a star, 6,500 light-years away.

The newly composed image was assembled from 24 individual Wide Field and Planetary Camera 2 exposures taken in October 1999, January 2000, and December 2000. The colors in the image indicate the different elements that were expelled during the explosion. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly-ionized sulfur, and red indicates doubly-ionized oxygen.
He1523a.jpg
Author/Creator: ESO, European Southern Observatory, Licence: CC BY 4.0
Artist's impression of "the oldest star of our Galaxy": HE 1523-0901
  • About 13.2 billion years old
  • Approximately 7500 light years far from Earth
  • Published as part of Hamburg/ESO Survey in the May 10 2007 issue of The Astrophysical Journal
Earth-moon.jpg
This view of the rising Earth greeted the Apollo 8 astronauts as they came from behind the Moon after the fourth nearside orbit. Earth is about five degrees above the horizon in the photo. The unnamed surface features in the foreground are near the eastern limb of the Moon as viewed from Earth. The lunar horizon is approximately 780 kilometers from the spacecraft. Width of the photographed area at the horizon is about 175 kilometers. On the Earth 240,000 miles away, the sunset terminator bisects Africa.
Solar system.jpg
This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. The spacecraft responsible for these images are as follows:
  • the Mercury image was taken by Mariner 10,
  • the Venus image by Magellan,
  • the Earth and Moon images by Galileo,
  • the Mars image by Mars Global Surveyor,
  • the Jupiter image by Cassini, and
  • the Saturn, Uranus and Neptune images by Voyager.
  • Pluto is not shown as it is no longer a planet. The inner planets (Mercury, Venus, Earth, Moon, and Mars) are roughly to scale to each other; the outer planets (Jupiter, Saturn, Uranus, and Neptune) are roughly to scale to each other. PIA 00545 is the same montage with Neptune shown larger in the foreground. Actual diameters are given below:
  • Sun (to photosphere) 1,392,684 km
  • Mercury 4,879.4 km
  • Venus 12,103.7 km
  • Earth 12,756.28 km
  • Moon 3,476.2 km
  • Mars 6,804.9 km
  • Jupiter 142,984 km
  • Saturn 120,536 km
  • Uranus 51,118 km
  • Neptune 49,528 km
Earth poster.svg
Author/Creator: Kelvinsong, Licence: CC BY-SA 3.0
Diagram of the Earth.