Magma ocean

Magma oceans are periods during Earth's or any planet's accretion where a large part or even the whole planet is molten.[1] In the early solar system, energy to melt objects came largely from the decay of radioactive aluminum-26.[2] As planets grew larger, the energy was supplied from large or giant impacts.[3] During its formation, the Earth likely suffered a series magma oceans resulting from giant impacts,[4] the final one being the Moon-forming impact.

Magma oceans are integral parts of planetary formation as they facilitate formation of a core through metal segregation[5] and an atmosphere and hydrosphere through degassing.[6] Magma oceans may survive for millions to tens of millions of years, interspersed by relatively clement conditions.

Magma oceans are widely accepted to have existed on Earth, and the best chemical evidence for them is the abundance of certain siderophile elements in the mantle that record magma ocean depths of approximately 1000 km during accretion.[7][8] A magma ocean also occurred on the Moon during and following its formation.

References

  1. ↑ Elkins-Tanton, Linda T. (2012-01-01). "Magma Oceans in the Inner Solar System". Annual Review of Earth and Planetary Sciences. 40 (1): 113–139. doi:10.1146/annurev-earth-042711-105503.
  2. ↑ Urey, Harold C. (1955-03-01). "The Cosmic Abundances of Potassium, Uranium, and Thorium and the Heat Balances of the Earth, the Moon, and Mars". Proceedings of the National Academy of Sciences. 41: 127–144. doi:10.1073/pnas.41.3.127. ISSN 0027-8424.
  3. ↑ Tonks, W. Brian; Melosh, H. Jay (1993-03-25). "Magma ocean formation due to giant impacts". Journal of Geophysical Research: Planets. 98 (E3): 5319–5333. doi:10.1029/92JE02726. ISSN 2156-2202.
  4. ↑ Tucker, Jonathan M.; Mukhopadhyay, Sujoy (2014-05-01). "Evidence for multiple magma ocean outgassing and atmospheric loss episodes from mantle noble gases". Earth and Planetary Science Letters. 393: 254–265. doi:10.1016/j.epsl.2014.02.050.
  5. ↑ Rubie, D. C.; Nimmo, F.; Melosh, H. J. (2007-01-01). Formation of Earth's Core. Amsterdam: Elsevier. pp. 51–90. ISBN 9780444527486.
  6. ↑ Zahnle, Kevin; Arndt, Nick; Cockell, Charles; Halliday, Alex; Nisbet, Euan; Selsis, Franck; Sleep, Norman H. (2007-01-01). Fishbaugh, Kathryn E.; Lognonné, Philippe; Raulin, François; Marais, David J. Des; Korablev, Oleg, eds. Emergence of a Habitable Planet. Space Sciences Series of ISSI. Springer New York. pp. 35–78. doi:10.1007/978-0-387-74288-5_3. ISBN 9780387742878.
  7. ↑ Li, Jie; Agee, Carl B. (1996-06-20). "Geochemistry of mantle–core differentiation at high pressure". Nature. 381 (6584): 686–689. doi:10.1038/381686a0.
  8. ↑ Righter, K.; Drake, M. J.; Yaxley, G. (1997-03-01). "Physical and Chemical Evolution of the EarthPrediction of siderophile element metal-silicate partition coefficients to 20 GPa and 2800°C: the effects of pressure, temperature, oxygen fugacity, and silicate and metallic melt compositions". Physics of the Earth and Planetary Interiors. 100 (1): 115–134. doi:10.1016/S0031-9201(96)03235-9.
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