Авторы: Levi S., Merill R.

1976 г.

Phys.Earth Planet.Int.

      Experiments comparing anhysteretic remanence (ARM) and thermoremanence (TRM) in samples containing natural and synthetic magnetite, whose mean particle sizes range from singl 9 domain to multidomain, show that ARM and TRM are very similar (but not identical) in their stabilities with respect to alternating field (AF) demagnetization, temperature cycles in zero field to below magnetite's isotropic temperature near 130°K, and stabifity with respect to spontaneous decay in zero field. Therefore, for magnetites, ARM can be used to model (with reasonable success) these stability properties of TRM. The field dependence of the acquisition of ARM and TRM shows that the low field susceptibility ratio, XARM/XTRM, has a particle size dependence, increasing from 0.1 for certain submicron particles to 2.0 for large multidomain crystals. Even for samples whose remanence is predominantly carried by submicron particles ×ARM/XTR M is highly variable, 0.11 ~< XARM/XTR M <~ 0.50. Therefore, ARM paleointensity methods which do not take into account the large variability in and the particle size dependence of ×ARM/XTRM are subject to order-of-magnitude uncertainties.

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