EarthRef.org Reference Database (ERR) -- Lowrie 1990

The common ferromagnetic minerals have distinctive, characteristic coercivities and thermomagnetic properties. The analysis of the acquisition curve of isothermal remanent magnetization (IRM) is a useful but often ambiguous diagnostic technique. For a more conclusive interpretation, IRM acquistion must be combined with subsequent thermal demagnetization of the IRM. A modification of this method is proposed as a more powerful analytical technique. Different coercivity fractions of IRM are remagnetized in successively smaller fields along three orthogonal directions. The thermal demagnetization of each orthogonal component of the composite IRM is then plotted separately. This method often gives a clearer interpretation of the ferromagnetic mineral content of a rock. Examples are described for limestone and sandstone samples. ¿ American Geophysical Union 1990 The common ferromagnetic minerals have distinctive, characteristic coercivities and thermomagnetic properties. The analysis of the acquisition curve of isothermal remanent magnetization (IRM) is a useful but often ambiguous diagnostic technique. For a more conclusive interpretation, IRM acquistion must be combined with subsequent thermal demagnetization of the IRM. A modification of this method is proposed as a more powerful analytical technique. Different coercivity fractions of IRM are remagnetized in successively smaller fields along three orthogonal directions. The thermal demagnetization of each orthogonal component of the composite IRM is then plotted separately. This method often gives a clearer interpretation of the ferromagnetic mineral content of a rock. Examples are described for limestone and sandstone samples. ¿ American Geophysical Union 1990