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AN: GP21A-0119
TI: Frequency Dependent Susceptibility Analysis of Magnetic Carriers: Application to Fe-Oxides on Mars surface
AU: * Adachi, T
EM: tomoko.adachi@gsfc.nasa.gov
AF: Department of Physics, Catholic University of America, 200 Hannan Hall, 620 Michigan Ave NE, Washington, DC 20064, United States
AU: * Adachi, T
EM: tomoko.adachi@gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 691, Division of Solar System Exploration, Greenbelt, 20771, United States
AU: Kletetschka, G
EM: kletetschka@nasa.gov
AF: Department of Physics, Catholic University of America, 200 Hannan Hall, 620 Michigan Ave NE, Washington, DC 20064, United States
AU: Kletetschka, G
EM: kletetschka@nasa.gov
AF: NASA Goddard Space Flight Center, Code 691, Division of Solar System Exploration, Greenbelt, 20771, United States
AU: Kletetschka, G
EM: kletetschka@nasa.gov
AF: Institute of Geology, Academy of Science of the Czech Republic, Rozvojová 135, Prague, 165 02, Czech Republic
AU: Mikula, V
EM: mikula.vilem@ssedmail.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 691, Division of Solar System Exploration, Greenbelt, 20771, United States
AB: On Mars, Fe-oxides mineral phases (inferred/detected) are mainly magnetite, pyrrhotite, and hematite. Kletetschka et al., 2005 suggested that the grain size dependent potential may contribute to the Mars surface magnetic anomaly. Grain size of Fe-oxides may play a role for the magnetic signature and anomaly on Mars. According to Kletetschka et al., 2005, the larger the grain size, the larger the magnetization (in this case hematite's TRM). Weather they are magnetite, pyrrhotite or hematite, nano-phase or superparamagnetic grains may contribute to the absence of remanent magnetization on the surface of Mars. In this contribution we tackle how to resolve grain size variations by frequency dependent susceptibility measured on terrestrial hematite samples such as hemo-ilmenite from Allard Lake, Canada, Mars analogue concretions from Utah and Czech Republic, and hematite aggregates from Hawaii. The magnetic characteristics of hematite-goethite mineralogies of Utah and Czech concretions suggested (Adachi et al., 2007) that they contain super paramagnetic (SP) to single domain (SD) magnetic states. Coercivity spectra analysis from acquisition of isothermal remanent magnetization (IRM) data showed the distinct behaviors of hematite, goethite, and mixed composition of both. The estimated magnetic states are analyzed with the frequency-dependent susceptibility instrument (500-250,000 Hertz). The frequency- and size-dependent susceptibility for hematite, goethite, and magnetite are calibrated using the known size powdered (commercial) samples.
UR: http://lep694.gsfc.nasa.gov/gunther/gunther/publications.html
DE: 1517 Magnetic anomalies: modeling and interpretation
DE: 1518 Magnetic fabrics and anisotropy
DE: 1540 Rock and mineral magnetism
DE: 1595 Planetary magnetism: all frequencies and wavelengths
DE: 1599 General or miscellaneous
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting