HR: 1340h
AN: GP13A-0044    [Abstracts]
TI: Coercivity Distributions and Magnetic Particle Interactions From First-Order Reversal Curves (FORCs): Examples from Natural Materials and Software for Data Analysis
AU: * Acton, G
EM: acton@geology.ucdavis.edu
AF: University of California, Davis, Department of Geology, One Shields Avenue, Davis, CA 95616 United States
AU: Verosub, K L
EM: verosub@geology.ucdavis.edu
AF: University of California, Davis, Department of Geology, One Shields Avenue, Davis, CA 95616 United States
AU: Roth, A
EM: alroth@ucdavis.edu
AF: University of California, Davis, Department of Geology, One Shields Avenue, Davis, CA 95616 United States
AU: Linderholm, D
EM: linderholm@geology.ucdavis.edu
AF: University of California, Davis, Department of Geology, One Shields Avenue, Davis, CA 95616 United States
AB: FORC diagrams, which are constructed from multiple partial hysteresis curves, provide intriguing insights into coercivity distributions and magnetic particle interactions in both natural and man-made materials. To facilitate the use and interpretation of FORCs, we have written software to simplify and speed the process of constructing standard FORC diagrams, developed simple models to aid in interpreting the results, and constructed a catalog of FORC diagrams for a variety of common magnetic minerals and geologic materials. The software creates a number of associated plots that illustrate the micro-susceptibility, the trajectories of FORC paths, the FORC distribution in 3-D and inside the major hysteresis loop, and the instrumental drift during the measurement. The free software and the catalog of FORC diagrams are accessible from our web site (http://paleomag.ucdavis.edu). The FORC catalog can be used to understand how differences in a number of variables - the time taken in collecting each data point, the number of data collected, the filtering or smoothing used, and the signal-to-noise ratio - affect the resulting FORC diagram. The methodologies that we have developed show how FORC diagrams can be used to characterize and quantify coercivity distributions and magnetic interactions.
DE: 1519 Magnetic mineralogy and petrology
DE: 1540 Rock and mineral magnetism
DE: 1594 Instruments and techniques
DE: 5109 Magnetic and electrical properties (0925)
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005