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Geological consequences of super‐sized Earths
Author(s) -
O'Neill C.,
Lenardic A.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl030598
Subject(s) - planet , lithosphere , geology , terrestrial planet , habitability , planetary surface , buoyancy , geophysics , tectonics , plate tectonics , astrobiology , mantle (geology) , exoplanet , mantle convection , earth science , physics , astronomy , mechanics , seismology
The discovery of terrestrial‐scale extrasolar planets, and their calculated abundance in the galaxy, has prompted speculation on their surface conditions and thermal structure. Both are dependent on the tectonic regime of a planet, which is itself a function of the balance between driving forces, and the resistive strength of the lithosphere. Here we use mantle convection simulations to show that simply increasing planetary radius acts to decrease the ratio of driving to resisting stresses, and thus super‐sized Earths are likely to be in an episodic or stagnant lid regime. This effect is robust when associated increases in gravity are included, as the more dominant effect is increased fault strength rather than greater buoyancy forces. The thermo‐tectonic evolution of large terrestrial planets is more complex than often assumed, and this has implications for the surface and conditions habitability of such worlds.