HR: 1340h
AN: P33A-1016    [Abstracts]
TI: Geologic Windows Through Time on Mars
AU: * Dohm, J M
EM: jmd@hwr.arizona.edu
AF: University of Arizona, Department of Hydrology and Water Resources, Tucson, AZ 85721 United States
AU: Kerry, K E
EM: krisk@lpl.arizona.edu
AF: University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ 85721 United States
AU: Keller, J
EM: jkeller@lpl.arizona.edu
AF: University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ 85721 United States
AU: Baker, V R
EM: baker@hwr.arizona.edu
AF: University of Arizona, Department of Hydrology and Water Resources, Tucson, AZ 85721 United States
AU: Baker, V R
EM: baker@hwr.arizona.edu
AF: University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ 85721 United States
AU: Boynton, W V
EM: wboynton@lpl.arizona.edu
AF: University of Arizona, Lunar and Planetary Laboratory, Tucson, AZ 85721 United States
AU: Maruyama, S
EM: smaruyam@geo.titech.ac.jp
AF: Tokyo Institute of Technology, Department of Earth and Planetary Sciences, Meguro, 152-8551 Japan
AB: An overarching geologic theory, GEOMARS, coherently explains the various anomalies in the geologic history of Mars. Premises for a theory of martian geologic evolution include: (1) Mars is a water-rich terrestrial planet, (2) terrestrial planets should evolve through progressive stages of dynamical history (accretion, differentiation, tectonism) and mantle convection (magma ocean, plate tectonism, stagnant lid), and (3) the early history of Earth affords an analogue to the evolution of Mars. The theory describes the following major stages of evolution for Mars (from oldest to youngest): Stage 1 - shortly after accretion, Mars differentiates to a liquid metallic core, a mantle boundary (MBL) of high-pressure silicate mineral phases, upper mantle, magma ocean, thin komatiic crust, and convecting steam atmosphere; Stage 2- Mars cools to condense its steam atmosphere and transform its mode of mantle convection to plate tectonism. Subduction of water-rich oceanic crust initiates arc volcanism and transfers water, carbonates and sulfates to the mantle; Stage 3 - the core dynamo initiates, and the associated magnetosphere leads to conditions conducive to the development of near-surface life and photosynthetic production of oxygen; Stage 4 -accretion of thickened, continental crust and subduction of hydrated oceanic crust to the mantle boundary layer and lower mantle of Mars occurs; Stage 5 - the core dynamo stops during Noachian heavy bombardment while plate tectonism continues; Stage 6 - initiation of the Tharsis superplume (~between 4.0 and 3.8Ga) occurs, and Stage 7 - the superlume phase (stagnant-lid regime) of martian planetary evolution with episodic phases of volcanism and water outflows continues into the present. The GEOMARS Theory is testable through a multidisciplinary approach, including utilizing GRS-based information. Based on a synthesis of published geologic, paleohydrologic, topographic, geophysical, spectral, and elemental information, we have defined twelve geologic provinces that represent significant windows into the geologic evolution of Mars, unfolding the GEOMARS Theory.
DE: 5410 Composition
DE: 5443 Magnetospheres (2756)
DE: 5470 Surface materials and properties
DE: 5475 Tectonics (8149)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting