Nimmo, F. and Stevenson, D. J.
(2000)
Influence of early plate tectonics on the thermal evolution and magnetic field of Mars.
Journal of Geophysical Research E, 105
(E5).
pp. 11969-11979.
ISSN 0148-0227.
doi:10.1029/1999JE001216.
https://resolver.caltech.edu/CaltechAUTHORS:20140415-144224473
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Abstract
Recent magnetic studies of Mars suggest that (1) it possessed a periodically reversing magnetic field for the first ∼500 Myr of its existence and (2) plate tectonics may have been operating during this time. On Earth the geodynamo is thought to occur because of convection in the outer core. This paper estimates the amount of heat the Martian core can conduct in the absence of convection. It uses parameterized, variable-viscosity thermal evolution models to show that the core heat flux increases if the planet's surface heat flux is increased above the value required to eliminate instantaneous radiogenic heat production. Conversely, a sudden reduction in surface heat flux causes the mantle to heat up and the core heat flux to become negative. Thus, if plate tectonics, or some other process causing high surface heat flux, was occurring on early Mars, it is likely to have caused convection in the core and hence generated a magnetic field. Conversely, a reduction in surface heat flux would probably have caused the core to stop convecting and shut off the magnetic field. There is thus an important link between surface processes and core magnetism, which may also be relevant to planets such as Earth and Venus.
Item Type: | Article |
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Additional Information: | © 2000 American Geophysical Union.
Received November 12, 1999; revised March 3, 2000; accepted March 10, 2000.
We thank Slava Solomatov and an anonymous reviewer, whose comments greatly improved this manuscript. This research was funded by Magdalene College, Cambridge, and the California Institute of Technology. |
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Funders: | Funding Agency | Grant Number |
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Magdalene College Cambridge | UNSPECIFIED | Caltech | UNSPECIFIED |
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Subject Keywords: | Planetology: Solar System Objects: Mars; Planetology: Solid Surface Planets: Heat flow; Planetology: Solid Surface Planets: Magnetic fields and magnetism; Planetology: Solid Surface Planets: Meteorology |
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Other Numbering System: | Other Numbering System Name | Other Numbering System ID |
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AGU Paper Number | 1999JE001216 |
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Issue or Number: | E5 |
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DOI: | 10.1029/1999JE001216 |
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Record Number: | CaltechAUTHORS:20140415-144224473 |
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Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20140415-144224473 |
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Official Citation: | Nimmo, F., and D. J. Stevenson (2000), Influence of early plate tectonics on the thermal evolution and magnetic field of Mars, J. Geophys. Res., 105(E5), 11969–11979, doi:10.1029/1999JE001216 |
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Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. |
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ID Code: | 44964 |
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Collection: | CaltechAUTHORS |
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Deposited By: |
Tony Diaz
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Deposited On: | 18 Apr 2014 17:17 |
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Last Modified: | 10 Nov 2021 16:58 |
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