HR: 14:10h
AN: P33C-03    [Abstracts]
TI: Temporally Transitional Mantle Convection: Implications for Mars
AU: * Loddoch, A
EM: loddoch@earth.uni-muenster.de
AF: Institute f. Geophysics, University of Muenster, Corrensstr. 24, Muenster, 48149, Germany
AU: Hansen, U
EM: hansen@earth.uni-muenster.de
AF: Institute f. Geophysics, University of Muenster, Corrensstr. 24, Muenster, 48149, Germany
AB: The thermal evolution of terrestrial planets such as Earth, Mars and Venus is strongly dominated by the convective processes in the planet's silicate mantle. The actual planform of convection controls the efficiency of heat transport and thus, the cooling behavior and thermal evolution of the whole planet. In the present study we investigate the heat transport properties of variable viscosity convection. Here, the focus is on the temporally transitional behavior discovered recently (Loddoch et. al, 2006). While the difference of the newly found convective regime to the already known stagnant lid and episodic behavior has been elaborated in our previous study, the present work investigates the implications of the observed intermittent behavior on the thermal evolution of terrestrial planets. A 3D numerical mantle convection code is applied and calculations are carried out in the parameter range for which the temporally transitional behavior has been found. Using the described approach it is possible to investigate the transition from a (temporarily) mobilized towards a stagnant surface in a fluid dynamically consistent manner. While such a scenario has repeatedly been suggested for Mars' early history, it has so far been investigated only by means of parameterized convection models. We show, that the sporadic surface mobilization events occur on time scales relevant for Mars. In order to assess their influence on the subsequent thermal evolution of planetary bodies, an internal heating of the mantle and a secular cooling of the core are additionally taken into account. The obtained results are compared to the findings of thermal evolution studies employing parameterized convection models.
DE: 5418 Heat flow
DE: 5430 Interiors (8147)
DE: 5475 Tectonics (8149)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8121 Dynamics: convection currents, and mantle plumes
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting