Magnetic properties and remanent magnetization of stony meteorites.

Abstract

Hysteresis parameters and remanence properties of 22 stony meteorites were measured. Coercive force varies systematically in the sequence E→H→L→LL→C chondrites. The change of natural remanent magnetization (NRM) stability follows the same sequence. Intensity of NRM is proportional to ferromagnetic mineral contents in meteorites. The ratio NRM/saturation magnetization is unrelated to the chemical class. Stability of NRM against alternating field demagnetization was compared to anhysteretic remanence (ARM) induced in a low field. The NRM in four meteorites is as stable as the ARM, and chemical remanence (CRM) or thermoremanence (TRM) origin of the NRM is inferred. NRM in eight meteorites is less stable than ARM. Stability and/or intensity of NRM was compared with that of isothermal remanence (IRM) and viscous remanence (VRM) and partial thermoremanence (pTRM). Artificial IRM and terrestrial VRM origin for NRM is ruled out; pTRM origin (acquired in the temperature range 20<T<200-300°C and in a field 0.5≤h≤2Oe) of NRM in some meteorites seems likely, since such pTRM exhibits almost identical behavior with NRM.