Gyroremanent Magnetization Research Articles

Gyroremanent magnetization in a weakly anisotropic rock sample

Gyroremanent magnetization (GRM) has been detected in a rock sample which, from initial susceptibility measurements, is only weakly anisotropic ( ⋍ 1%). In accordance with theory the GRM is independent of the frequency of the alternating field for frequencies of 50 and 274 Hz.

Alternating field demagnetization of rocks, and the problem of gyromagnetic remanence

Alternating field (a.f.) demagnetization has proved to be a very reliable technique for separating the magnetization components of rock samples. The method is subject to errors caused by either imperfection of the technique or by intrinsic properties of a rock. Recently, Stephenson [1,2] introduced the term gyroremanent magnetization (GRM) for a disturbing remanent magnetization that can be acquired by magnetic material during tumbling or stationary a.f. demagnetization. The implications for the routine a.f. demagnetization of anisotropic rock samples seemed to be very serious. Here, however, a method is presented on how to avoid the effect of GRM on results obtained from stationary a.f. demagnetization.