Conditions for the onset of plate tectonics on terrestrial planets and moons

C. O'Neill*, A. M. Jellinek, A. Lenardic

*Corresponding author for this work

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

Plate tectonics on Earth is driven by the subduction and stirring of dense oceanic lithosphere into the underlying mantle. For such a regime to exist on any planet, stresses associated with mantle convection must exceed the strength of the lithosphere. This condition is sufficiently restrictive that plate tectonics currently operates only on Earth, and mantle convection in most terrestrial planets and moons is probably in a stagnant lid regime. Convective stresses on the lithosphere depend on the viscosity and velocity of underlying cold downwellings. The lithospheric yield stress is controlled by its friction coefficient and elastic thickness (the depth to the brittle-ductile transition or BDT). Both convective stresses and the plate's yield strength depend critically on the size, thermal state and cooling history of a planet. Accordingly, here we use numerical simulations and scaling theory to identify conditions in which mantle convection leads to lithospheric failure for a range of conditions relevant to the terrestrial planets. Whereas Earth is expected to be in a plate-tectonic regime over its full thermal evolution, the Moon and Mercury are expected to have always remained in a stagnant lid regime. Venus, Io and Europa currently fall on the transition between the two regimes, which is consistent with an episodic style of mantle convection for Venus, a tectonic component to deformation on Io, and the resurfacing history and lithospheric evolution of Europa. Our results suggest that Venus may have been in a plate-tectonic regime in the past. While stagnant now, it is plausible that Mars may have also been in an active-lid regime, depending on whether there was liquid water on the surface.

Original languageEnglish
Pages (from-to)20-32
Number of pages13
JournalEarth and Planetary Science Letters
Volume261
Issue number1-2
DOIs
Publication statusPublished - 15 Sep 2007
Externally publishedYes

Keywords

  • lithosphere
  • mantle convection
  • plate tectonics
  • terrestial planets

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