Remanent magnetization (remanence)
Natural remanent magnetization (NRM), or remanence, is the permanent magnetization that exists in magmatic and sedimentary rocks and forms part of the total magnetization of a rock. It is originally blocked parallel to the Earth’s magnetic field. In basic petrophysical measurements the magnitude of remanence is measured. If the sample is oriented, the direction of remanence is also defined.
In basic measurements, remanent magnetization can be measured on hand samples (100-200 cm3) or on drill core samples. Measurements are made with a fluxgate magnetometer inside μ-metal shielding. More accurate measurements are carried out only in the Espoo laboratory (see below).
