Magnetism of nakhlites and chassignites. Final Technical Report, 1 March 1984-28 February 1985
Hysteresis measurements on three shergottite and two nakhlite meteorites indicate single domain grain size behavior for the highly shocked Shergotty, Zagami, and EETA 79001 meteorites, with more multidomain-like behavior for the unshocked Nakhla and Governador Valadares meteorites. High viscosity and initial susceptibility for Antarctic shergottite ALHA 7705 indicate the presence of superparamagnetic grains in this specimen. Thermomagnetic analysis indicate Shergotty and Zagami as the least initially oxidized, while EETA 79001 appears to be the most oxidized. Cooling of the meteorite samples from high temperature in air results in a substantial increase in magnetization due to the production of magnetite through oxidation exsolution of titanomagnetite. However, vacuum heating substantially suppresses this process, and in the case of EETA 79001 and Nakhla, results in a rehomogenization of the titanomagnetite grains. Remanence measurements on several subsamples of Shergotty and Zagami meteorites reveal a large variation in intensity that does not seem related to the abundance of remanence carriers. The other meteorites carry only weak remanence, suggesting weak magnetizing fields as the source of their magnetic signal. The meteorites weak field environment is consistent with Martian or asteroidal body origin but inconsistent with terrestrial origin.
- Research Organization:
- California Univ., Santa Barbara (USA)
- OSTI ID:
- 5797016
- Report Number(s):
- N-86-20277; NASA-CR-176518
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACHONDRITES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DATA
ELEMENTS
EXPERIMENTAL DATA
GRAIN SIZE
HYSTERESIS
INFORMATION
IRON COMPOUNDS
IRON ORES
IRON OXIDES
MAGNETIC PROPERTIES
MAGNETISM
MAGNETITE
METALS
METEORITES
MICROSTRUCTURE
MINERALS
NUMERICAL DATA
ORES
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PALEOMAGNETISM
PHYSICAL PROPERTIES
SIZE
STONE METEORITES
TITANIUM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS