Mantle (geology)

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The structur o the Yird

The mantle is a pairt o a terrestrial planet or ither rocky body lairge enough tae hae differentiation bi density. The interior o the Yird, similar tae the ither terrestrial planets, is chemically dividit intae layers. The mantle is a layer atween the crust an the ooter core. Yird's mantle is a silicate rocky shell aboot 2,900 km (1,800 mi) thick[1] that constitutes aboot 84% o Yird's volume.[2] It is predominantly solid but in geological time it behaves lik very viscous liquid. The mantle encloses the het core rich in iron an nickel, which occupies aboot 15% o Yird's volume.[2][3] Past episodes o meltin an volcanism at the shallaer levels o the mantle hae produced a thin crust o crystallized melt products near the surface, upon which we live.[4] Information aboot structure an composeetion o the mantle either result frae geopheesical investigation or frae direct geoscientific analyses on Yird mantle derived xenoliths.

Twa main zones are distinguished in the upper mantle: the inner asthenosphere componed o plastic flaein rock aboot 200 km thick,[5] an the lawermaist pairt o the lithosphere componed o rigid rock aboot 50 tae 120 km thick.[6] A thin crust, the upper pairt o the lithosphere, surroonds the mantle an is aboot 5 tae 75 km thick.[7]

In some places unner the ocean the mantle is actually exponed on the surface o the Yird.[8] Thare are an aa a few places on land whaur mantle rock haes been pushed tae the surface bi tectonic activity, maist notably the Tablelands region o Gros Morne Naitional Pairk in the Canadian province o Newfoundland an Labrador.

References[eedit | eedit soorce]

  1. Mantle: Schlumberger Oilfield Glossary. Glossary.oilfield.slb.com. Retrieved on 2013-05-11.
  2. 2.0 2.1 Robertson, Eugene (2007). "The interior of the earth". USGS. Retrieved 2009-01-06. 
  3. Core: Schlumberger Oilfield Glossary. Glossary.oilfield.slb.com. Retrieved on 2013-05-11.
  4. "The structure of the Earth". Moorland School. 2005. Retrieved 2007-12-26. 
  5. Asthenosphere: Schlumberger Oilfield Glossary. Glossary.oilfield.slb.com. Retrieved on 2013-05-11.
  6. Lithosphere: Schlumberger Oilfield Glossary. Glossary.oilfield.slb.com. Retrieved on 2013-05-11.
  7. Crust: Schlumberger Oilfield Glossary. Glossary.oilfield.slb.com. Retrieved on 2013-05-11.
  8. Mission to Study Earth's Gaping 'Open Wound'. LiveScience. Retrieved on 2013-05-11.