Thermal evolution of the Martian core: Implications for an early dynamo

Research Article| February 01, 2004 Thermal evolution of the Martian core: Implications for an early dynamo Jean-Pierre Williams; Jean-Pierre Williams 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA Search for other works by this author on: GSW Google Scholar Francis Nimmo Francis Nimmo 2Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK, and Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jean-Pierre Williams 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA Francis Nimmo 2Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK, and Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA Publisher: Geological Society of America Received: 25 Jun 2003 Revision Received: 14 Oct 2003 Accepted: 15 Oct 2003 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (2): 97–100. https://doi.org/10.1130/G19975.1 Article history Received: 25 Jun 2003 Revision Received: 14 Oct 2003 Accepted: 15 Oct 2003 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Jean-Pierre Williams, Francis Nimmo; Thermal evolution of the Martian core: Implications for an early dynamo. Geology 2004;; 32 (2): 97–100. doi: https://doi.org/10.1130/G19975.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Mars is thought to have possessed a dynamo that ceased ∼0.5 b.y. after the formation of the planet. A possible, but ad hoc, explanation is an early episode of plate tectonics, which drove core convection by rapid cooling of the mantle. We present an alternative explanation: that the Martian core was initially hotter than the mantle after core formation, providing an initial high heat flux out of the core. A core initially 150 K hotter than the mantle can explain the early dynamo without requiring plate tectonics. Recent experimental results suggest that potassium is likely to partition into the Martian core, potentially providing an extra source of energy to power a dynamo. We find that the radioactive decay of 40K cannot explain the inferred dynamo history without the presence of a hot core. Our results also suggest that core solidification is unlikely to have occurred, because this process would have generated a long-lived (>1 b.y.) dynamo. If, as we conclude, the core is entirely liquid, it must contain at least ∼5 wt% sulfur. An initially hot core is consistent with geochemical evidence for rapid core formation and incomplete thermal equilibration with the mantle. Thus, the early history of planetary dynamos provides constraints on the processes of accretion and differentiation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.