Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition

Details Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition

Dec 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003agufmgp21c0040r&link_type=abstract

American Geophysical Union, Fall Meeting 2003, abstract #GP21C-0040

Mathematics

Logic

1519 Magnetic Mineralogy And Petrology, 1533 Remagnetization, 3924 High-Pressure Behavior, 5440 Magnetic Fields And Magnetism

Scientific paper

In mineralogical and rock magnetic studies of meteorites, pyrrhotite has been somewhat underscored due to misidentification with troilite and to the poor knowledge of its magnetic properties until the nineties. In the common case of pyrrhotite-magnetite (or metal) mixtures, remanence may be mainly carried by pyrrhotite while thermomagnetic curves points toward metal or magnetite. We have now studied 20 (among a total of 28) independent martian meteorites (SNCs) and found that among the 18 strongly magnetic ones (Mrs more than 10 A/m), 9 have their magnetic remanence carried by pyrrhotite. Among the chondrites, rumurutites (R) contain only pyrrhotite, while a number of carbonaceaous chondrites (including Allende) contain mixture with metal or magnetite. Low unblocking temperatures combined with high AF resistance of NRM may point toward pyrrhotite (or other sulfides) as the main NRM carrier in various published studies. A high-pressure transition to non-magnetic state has been pinpointed to 2.8 GPa (Rochette et al., 2003; GRL doi:10.1029/ 2003GL017359). Remanence measurements on well characterized nearly SD pyrrhotite confirm full demagnetization at this pressure, and 3/4 at 2 GPa. As the majority of meteorites (including all SNCs) has been shocked much above this pressure this implies that the pyrrhotite NRM is post-shock even in meteorites considered to be considered to be "unshocked". Indeed the threshold for petrographic shock evidence is 4-5 GPa. This shock demagnetization may also explain the lack of magnetization at several crater radii from the large impact basins on Mars (Hood et al., 2003; GRL doi10.1029/2002GL016657).

Affiliated with

Also associated with

No associations

Rating

Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pyrrhotite in Extraterrestrial Materials: Paleomagnetic Implications of its High-Pressure Transition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1427092