Other
Scientific paper
Jul 1998
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998m%26ps...33..743m&link_type=abstract
Meteoritics & Planetary Science, vol. 33, no. 4, pp. 743-751.
Other
13
Scientific paper
We examined decomposition products of lepidocrocite, which were produced by heating the phase in air at temperatures up to 525(C for 3 and 300 hr, by XRD, TEM, magnetic methods, and reflectance spectroscopy (visible and near-IR). Single-crystal lepidocrocite particles dehydroxylated to polycrystalline particles of disordered maghemite which subsequently transformed to polycrystalline particles of hematite. Essentially pure maghemite was obtained at 265 and 223(C for the 3 and 300 hr heating experiments, respectively. Its saturation magnetization (Js) and mass specific susceptibility are ~50 Am2/kg and ~400 x 10-6 m3/kg, respectively. Because hematite is spectrally dominant, spectrally-hematitic samples (i.e., a minimum near 860 nm and a maximum near 750 nm) could also be strongly magnetic (Js up to ~30 Am2/kg) from the masked maghemite component. TEM analyses showed that individual particles are polycrystalline with respect to both maghemite and hematite. The spectrally-hematitic and magnetic Mh+Hm particles can satisfy the spectral and magnetic constraints for Martian surface materials over a wide range of values of Mh/(Mh+Hm) either as pure oxide powders or (within limits) as components of multiphase particles. These experiments are consistent with lepidocrocite as the precursor of Mh+Hm assemblages on Mars, but other phases (e.g., magnetite) that decompose to Mh and Hm are also possible precursors. Simulations done with a copy of the Mars Pathfinder Magnet Array showed that spectrally hematitic Mh+Hm powders having Js equal to 20.6 Am2/kg adhered to all five magnets.
Golden D. C.
Lauer Howard V. Jr.
Morris Richard V.
Shelfer Tad D.
No associations
LandOfFree
Lepidocrocite to maghemite to hematite: A pathway to have magnetic and hematitic Martian soil 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 Lepidocrocite to maghemite to hematite: A pathway to have magnetic and hematitic Martian soil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lepidocrocite to maghemite to hematite: A pathway to have magnetic and hematitic Martian soil will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1268797