HR: 0830h
AN: GP21C-0044    [PDF]
TI: Evidence for Terrestrial Magnetic Contamination of the Chondritic Meteorites
AU: * Kohout, T
EM: kohout@natur.cuni.cz
AF: Department of Applied Geophysics, Faculty of Science, Charles University, Albertov 6, Prague 2, 12843 Czech Republic
AU: * Kohout, T
EM: kohout@natur.cuni.cz
AF: Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojova 135, Prague 6, 16502 Czech Republic
AU: Donadini, F
EM:
AF: Division of Geophysics, Department of Physical Sciences, University of Helsinki, Kampula, Helsinki, 00000 Finland
AU: Kletetschka, G
EM:
AF: Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojova 135, Prague 6, 16502 Czech Republic
AU: Kletetschka, G
EM:
AF: Institute of Astrophysics and Computational Sciences, Catholic University of America, Washington, DC, 00000
AU: Kletetschka, G
EM:
AF: NASA - Goddard Space Flight Center, Code 691, Greenbelt, MD 20771 United States
AU: Kobr, M
EM:
AF: Department of Applied Geophysics, Faculty of Science, Charles University, Albertov 6, Prague 2, 12843 Czech Republic
AU: Pesonen, L J
EM:
AF: Division of Geophysics, Department of Physical Sciences, University of Helsinki, Kampula, Helsinki, 00000 Finland
AU: Pruner, P
EM:
AF: Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojova 135, Prague 6, 16502 Czech Republic
AU: Wasilewski, P J
EM:
AF: NASA - Goddard Space Flight Center, Code 691, Greenbelt, MD 20771 United States
AB: Ordinary chondrites represent primitive material of the Solar System. They provide essential information about the conditions in the early solar nebula. Part of this information can be extracted by analyzing the magnetic properties of meteorites. However, the magnetic record and associated rock magnetic properties are sensitive to the meteorite's numerous post-formation processes including various metamorphic events during planet formation period or terrestrial residence following the meteorite's fall. As shown by the Moravka (H 5-6) and Zebrak (H 5) samples, some ordinary chondrites do not carry stable magnetic remanent record. The loss of primary magnetic remanence (if any) can be associated with metamorphic events that may have taken place before the encounter with the Earth. The soft magnetic component may indicate a viscous terrestrial magnetic contamination. Another (EL 6) meteorite is an example o f a fresh fall. The magnetic material of this chondrite seems to be sensitive to low temperature ($<$ 350 K) ambient magnetic field contamination. The meteorite (H 4) (from the El Baharya "strewn field" of the Libya desert) carries visible traces of terrestrial oxidation and weathering. The magnetic mineral assembly contains products of terrestrial oxidation and the magnetic record present was probably strongly influenced by terrestrial remagnetization. Therefore, numerous space and terrestrial processes reduce the chance of observing a primary magnetic record in ordinary chondrites.
UR: http://www.volny.cz/tomkohout/meteo/
DE: 1540 Rock and mineral magnetism
DE: 1594 Instruments and techniques
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2003 Fall Meeting