HR: 1340h
AN: GP43A-0893    [Abstracts]
TI: Single-Domain/Pseudo-Single-Domain Magnetic Particles in the Lower Crust of Mars: Source of the Strong Magnetic Anomalies
AU: * Arkani-Hamed, J
EM: jafar@physics.utoronto.ca
AF: Department of Physcis, University of Toronto, Toronto, ON M5S 1A7 Canada
AB: It is shown in this paper that single-domain or pseudo-single-domain magnetite grains can exist in the upper 30-45 km of the Martian crust. The upper ~50 km of the Martian crust has likely formed by volcanic eruptions on a stagnant lithosphere. A given lava flow cools very rapidly at the surface, but then is gradually heated up through burial heating as it is overlain by other successive flows. The thermal evolution models of a lava flow show that its temperature remains below the magnetic blocking temperatures of magnetite, 480-580C, until it reaches ~30-45 km depth. The highly magnetic single-domain or pseudo-single-domain magnetite grains can easily explain the strong magnetic anomalies of Mars, less than one percent by volume of magnetite particles is sufficient.
DE: 1517 Magnetic anomalies: modeling and interpretation
DE: 5440 Magnetic fields and magnetism
DE: 5499 General or miscellaneous
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005