Space Science Reviews

, Volume 174, Issue 1–4, pp 27–48

Core Formation and Mantle Differentiation on Mars

Article

DOI: 10.1007/s11214-012-9935-8

Cite this article as:
Mezger, K., Debaille, V. & Kleine, T. Space Sci Rev (2013) 174: 27. doi:10.1007/s11214-012-9935-8

Abstract

Geochemical investigation of Martian meteorites (SNC meteorites) yields important constraints on the chemical and geodynamical evolution of Mars. These samples may not be representative of the whole of Mars; however, they provide constraints on the early differentiation processes on Mars. The bulk composition of Martian samples implies the presence of a metallic core that formed concurrently as the planet accreted. The strong depletion of highly siderophile elements in the Martian mantle is only possible if Mars had a large scale magma ocean early in its history allowing efficient separation of a metallic melt from molten silicate. The solidification of the magma ocean created chemical heterogeneities whose ancient origin is manifested in the heterogeneous 142Nd and 182W abundances observed in different meteorite groups derived from Mars. The isotope anomalies measured in SNC meteorites imply major chemical fractionation within the Martian mantle during the life time of the short-lived isotopes 146Sm and 182Hf. The Hf-W data are consistent with very rapid accretion of Mars within a few million years or, alternatively, a more protracted accretion history involving several large impacts and incomplete metal-silicate equilibration during core formation. In contrast to Earth early-formed chemical heterogeneities are still preserved on Mars, albeit slightly modified by mixing processes. The preservation of such ancient chemical differences is only possible if Mars did not undergo efficient whole mantle convection or vigorous plate tectonic style processes after the first few tens of millions of years of its history.

Keywords

Core formation Magma ocean Chemical differentiation Mantle evolution Short-lived nuclides 

Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Klaus Mezger
    • 1
  • Vinciane Debaille
    • 2
  • Thorsten Kleine
    • 3
  1. 1.Institut für GeologieUniversität BernBernSwitzerland
  2. 2.Laboratoire G-TimeUniversité Libre de Bruxelles CP160/02BrusselsBelgium
  3. 3.Institut für PlanetologieWestfälische Wilhelms-Universität MünsterMünsterGermany

Personalised recommendations