HR: 1340h
AN: P13A-1040    [Abstracts]
TI: The morphology of Cerberus volcanic landforms and the conditions for the formation of fluid lavas
AU: * Baratoux, D
EM: baratoux@dtp.obs-mip.fr
AF: Observatoire Midi-Pyrénées Labratoire Dynamique Terrestre et Planétaire, UMR 5562 CNRS et Université Paul Sabatier Toulouse III, 14, Avenue Edouard Belin, Toulouse, 31400, France
AU: Vaucher, J
EM: vaucher@dtp.obs-mip.fr
AF: Observatoire Midi-Pyrénées Labratoire Dynamique Terrestre et Planétaire, UMR 5562 CNRS et Université Paul Sabatier Toulouse III, 14, Avenue Edouard Belin, Toulouse, 31400, France
AU: Pinet, P
EM: pinet@dtp.pbs-mip.fr
AF: Observatoire Midi-Pyrénées Labratoire Dynamique Terrestre et Planétaire, UMR 5562 CNRS et Université Paul Sabatier Toulouse III, 14, Avenue Edouard Belin, Toulouse, 31400, France
AU: Toplis, M J
EM: toplis@dtp.obs-mip.fr
AF: Observatoire Midi-Pyrénées Labratoire Dynamique Terrestre et Planétaire, UMR 5562 CNRS et Université Paul Sabatier Toulouse III, 14, Avenue Edouard Belin, Toulouse, 31400, France
AU: Mangold, N
EM: mangold@u-psud.fr
AF: Interactions et Dynamique des Environnements de Surface, UMR 8148 CRNS et Université Paris Sud, Centre Universitaire d'Orsay, Toulouse, 31 400, France
AU: Bibring, J
EM: bibring@ias.u-psud.fr
AF: Institut d'Astrophysique Spatiale, Centre universitaire d'Orsay Bat 120 - 121, Orsay, 31400, France
AB: The extremely smooth surface of flows observed on the Cerberus plains has been variably attributed to the role of volcanic flows, subsurface ice, and/or fluvial transport. In an attempt to clarify the debate concerning these flows a new high-resolution geological mapping of the recent unit of the Cerberus plains has been undertaken, thanks to which several new shield volcanoes have been identified [1]. Evidence for the occurrence of widespread volcanic material is reviewed, including morphologic observations and mineralogical compositions from OMEGA and TES observations. Indeed, it is important to note that the OMEGA spectra of exposed dark material of Cerberus are similar to some of those obtained in the Syrtis Major volcanic plateau composed of mafic materials. The various approaches are consistent and indicate that flows on Cerberus can be divided in two distinct groups according to their rheology. The first group has a similar viscosity to other volcanic landforms, to our present knowledge [3] while the second group is composed of extremely fluid lavas (viscosities as low as a few Pa.s), unique in the Martian context. We believe that formation of these fluid and recent lavas has strong implications for the understanding of the volcanic and thermal evolution of Mars. The degree of partial melting associated with volcanism in the Cerberus region is discussed in comparison with other volcanic provinces in light of (a) the thermal structure of the Martian lithosphere, which is likely to be thickening with time [4], (b) the different plausible mechanisms for volcanism on Mars[5], in particular for recent volcanism [6], and (c) from the abundance of incompatible elements, such as potassium and thorium from the available GRS maps. Given the possible ranges of degree of partial melting, we discuss several hypotheses concerning the formation of very fluid lavas, including the role of water and composition for the crystal growth rate during the emplacement of the lavas. [1] Vaucher et. al, in revision for Icarus [2] Baptista et. al, in revision for Journal of Geophysical Research [3] Hiesinger, H., J. W. Head III, and G. Neukum (2007), J. Geophys. Res., 112,E05011, doi:10.1029/2006JE002717. [4] McGovern, P. J., S. C. Solomon, D. E. Smith, M. T. Zuber, M. Simons, M. A. Wieczorek, R. J. Phillips, G. A. Neumann, O. Aharonson, and J. W. Head, J. Geophys. Res., 107 (E12), 5136, doi:10.1029/2002JE001854, 2002. [5] Weizmann A., D. J. Stevenson D. Prialnik and M. Podola, Icarus 150, 195-205 (2001) , doi:10.1006/icar.2000.6572 [6] S. Schumacher, and D. Breuer, Geophys. Res. Lett., 34, L14202, doi:10.1029/2007GL030083, 2007
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 6225 Mars
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
DE: 8439 Physics and chemistry of magma bodies
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting