HR: 0800h
AN: P51D-0971    [Abstracts]
TI: Modeling Ferrous-Ferric Iron Chemistry With Application to Martian Surface Geochemistry.
AU: * Marion, G M
EM: giles.marion@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512 United States
AU: Kargel, J S
EM: kargel@hwr.arizona.edu
AF: University of Arizona, Dept. of Hydrology & Water Resources, Tucson, AZ 85721 United States
AU: Catling, D C
EM: davidc@atmos.washington.edu
AF: University of Bristol, Dept. of Astronomy, Bristol, NV BS81RJ United Kingdom
AB: The Mars Exploration Rover (MER) missions have stimulated considerable thinking about the surficial geochemical evolution of Mars. Among the major MER findings is the presence of the mineral, jarosite (a ferric sulfate salt), which suggests formation from an acid-sulfate brine. The main objectives of this work were to add ferric iron chemistry to an existing ferrous iron/acid sulfate chemical thermodynamic model (FREZCHEM), and to use this model to simulate the geochemical evolution of the Martian surface. In this work, we parameterized the FREZCHEM model for ferric iron chemistry using the Pitzer approach. New iron minerals added to the model include jarosite (K, H, and Na varieties), ferricopiapite, coquimbite, and schwertmannite. These particular iron minerals were chosen because they frequently form from acidic brines on Earth. The Martian simulations will examine how brine chemistries, iron chemistries, acidity, and the redox environment control the surficial geochemistry of Mars.
DE: 1000 GEOCHEMISTRY
DE: 1009 Geochemical modeling (3610, 8410)
DE: 5470 Surface materials and properties
DE: 6200 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005