Natural remanent magnetization

Natural remanent magnetization (NRM) the magnetization of a sample that has not been subject an external magnetic field. 

M-r is the magnitude of the (natural) remanent magnetization (per imit volume), K is the volume susceptibility, and H is the magnitude of the earth s magnetic field at the site. 

The natural remanent magnetization (NRM) is the field-independent and irreversible part of the total magnetization. There are different types and origins of this phenomenon in rocks as follows ... 

FIGURE 10.11 Natural remanent magnetization (NRM) and susceptibility measured at cores of the KTB (Continental Deep Drilling Program, Germany). Vertical axis depth in metre M meta-basite, BG biotite-gneiss, G gneiss. After Lippmann et al. (1989). 

To further confirm the nature of magnetic interactions, the isothermal remanence magnetization (IRM) curve Mr(H) and DC demagnetization (DCD) curve A1d(H), both normalized to the saturation remanence, have been plotted at 20K. From these curves, a Henkel plot has been obtained (Fig. 2l.l0a). In a perfectly noninteracting system of single-domain particles, the slope of the Henkel plot should be —2 and the experimental points would lie on the upper limit of this plot [37], The types of interactions are characterized by means of 8M plots (Fig. 21. lOb) obtained using the following relation ... 

Biogenic magnetite may persist once the organism that produced it has died and may, therefore, contribute to the natural magnetic remanence of sediments (Stolz et al., 1986). The discovery in a calcareous Martian ( ) meteorite found in Antarctica, of magnetite crystals with properties very similar to these biogenic magnetites, sup-... 

In order to describe this phenomenon, remanence curves provide insight into magnetic interactions through the use of the delta M (SAT) formalism which classifies the nature of interactions present via the relation [5]... 

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