Papers on Geomagnetism and Paleomagnetism Marine Geology and Geophysics
First-order reversal curve diagrams: A new tool for characterizing the magnetic properties of natural samples
Article first published online: 20 SEP 2012
Copyright 2000 by the American Geophysical Union.
Journal of Geophysical Research: Solid Earth (1978–2012)
Volume 105, Issue B12, pages 28461–28475, 10 December 2000
How to Cite
2000), First-order reversal curve diagrams: A new tool for characterizing the magnetic properties of natural samples, J. Geophys. Res., 105(B12), 28461–28475, doi:10.1029/2000JB900326., , and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 30 AUG 2000
- Manuscript Received: 12 APR 2000
Paleomagnetic and environmental magnetic studies are commonly conducted on samples containing mixtures of magnetic minerals and/or grain sizes. Major hysteresis loops are routinely used to provide information about variations in magnetic mineralogy and grain size. Standard hysteresis parameters, however, provide a measure of the bulk magnetic properties, rather than enabling discrimination between the magnetic components that contribute to the magnetization of a sample. By contrast, first-order reversal curve (FORC) diagrams, which we describe here, can be used to identify and discriminate between the different components in a mixed magnetic mineral assemblage. We use magnetization data from a class of partial hysteresis curves known as first-order reversal curves (FORCs) and transform the data into contour plots (FORC diagrams) of a two-dimensional distribution function. The FORC distribution provides information about particle switching fields and local interaction fields for the assemblage of magnetic particles within a sample. Superparamagnetic, single-domain, and multidomain grains, as well as magnetostatic interactions, all produce characteristic and distinct manifestations on a FORC diagram. Our results indicate that FORC diagrams can be used to characterize a wide range of natural samples and that they provide more detailed information about the magnetic particles in a sample than standard interpretational schemes which employ hysteresis data. It will be necessary to further develop the technique to enable a more quantitative interpretation of magnetic assemblages; however, even qualitative interpretation of FORC diagrams removes many of the ambiguities that are inherent to hysteresis data.