Mantle (geology) explained

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.

Examples

Earth

See main article: Earth's mantle. 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 2900km (1,800miles) 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 planets

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

Moons

Jupiter's moons Io, Europa, and Ganymede have silicate mantles; Io's ~1100abbr=offNaNabbr=off silicate mantle is overlain by a volcanic crust, Ganymede's ~1315abbr=offNaNabbr=off thick silicate mantle is overlain by ~835abbr=offNaNabbr=off of ice, and Europa's ~1165abbr=offNaNabbr=off km silicate mantle is overlain by ~85abbr=offNaNabbr=off 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.^[4] The lunar mantle might be exposed in the South Pole-Aitken basin or the Crisium basin. The lunar mantle contains a seismic discontinuity at ~500abbr=offNaNabbr=off depth, most likely related to a change in composition.

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

Asteroids

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

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.
• Book: Jeanloz, Raymond . Raymond Jeanloz . Haraldur Sigurdsson . Bruce Houghton . Hazel Rymer . John Stix . Steve McNutt . Encyclopedia of Volcanoes . Mantle of the Earth . 2000 . . San Diego . 41–54 . 978-0-12-643140-7.
• 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) (archived 17 October 2007)
• Information on the Mohole Project (archived 2 November 2015)

Notes and References

1. Book: Katharina., Lodders. Katharina Lodders . The planetary scientist's companion . 1998 . . Fegley, Bruce. . 978-1423759836 . New York . 65171709.
2. News: 2016-03-26 . What is the Earth's Mantle Made Of? – Universe Today . en-US . . 2018-11-24.
3. Swindle . T. D. . 2002-01-01 . Martian Noble Gases . . en . 47 . 1 . 171–190 . 2002RvMG...47..171S . 10.2138/rmg.2002.47.6 . 1529-6466.
4. Wieczorek. M. A.. 2006-01-01. The Constitution and Structure of the Lunar Interior. Reviews in Mineralogy and Geochemistry. en. 60. 1. 221–364. 10.2138/rmg.2006.60.3. 2006RvMG...60..221W. 1529-6466.
5. Web site: Layers of Titan. 23 February 2012. NASA. 7 October 2015. https://web.archive.org/web/20150914203834/http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4468. 14 September 2015. dead.
6. Web site: Triton: In Depth. NASA. 16 October 2015. https://web.archive.org/web/20151117013842/http://solarsystem.nasa.gov/planets/triton/indepth. 17 November 2015. dead.
7. Web site: Griffith Observatory – Pieces of the Sky – Meteorite Histories. www.griffithobservatory.org. en-us. 2018-11-24. 2020-02-10. https://web.archive.org/web/20200210150912/http://www.griffithobservatory.org/exhibits/edgeofspace_piecesofthesky-histories.html. dead.
8. 2011-03-01. First fragment of Asteroid 4 Vesta's mantle detected. Icarus. en. 212. 1. 175–179. 10.1016/j.icarus.2010.11.032. 0019-1035. Reddy. Vishnu. Nathues. Andreas. Gaffey. Michael J.. 2011Icar..212..175R.