natural remanent magnetism (NRM) The remanent magnetization of rocks and naturally occurring objects that has been acquired by normal processes, i.e. excluding laboratory-induced magnetizations. In igneous rocks and fired archaeological materials, NRM is normally of thermal or chemical origin; in sediments it is usually of depositional origin; and in sedimentary rocks it is usually of chemical origin.

natural remanent magnetism (NRM) The remanent magnetization of rocks and naturally occurring objects which has been acquired by normal processes. In igneous rocks and fired archaeological materials, NRM is normally of thermal or chemical origin; in sediments it is usually of depositional origin; and in sedimentary rocks it is usually of chemical origin.