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Yu et al. 2002
Yu, Y., Dunlop, D.J. and Özdemir, Ö. (2002). Partial anhysteretic remanent magnetization in magnetite 2. Reciprocity. Journal of Geophysical Research 107: doi: 10.1029/2001JB001269. issn: 0148-0227.

One necessary condition for successful determination of relative paleomagnetic field intensity using anhysteretic remanent magnetization (ARM) methods is reciprocity: a partial ARM, produced by a steady field H applied over a narrow interval ($widetilde{H}$2, $widetilde{H}$1) of alternating field (AF), must demagnetize over the same interval ($widetilde{H}$2, $widetilde{H}$1). Experimentally, we find that partial ARMs of single-domain (SD) and pseudosingle-domain (PSD) grains demagnetize mainly between $widetilde{H}$2 and $widetilde{H}$1, whereas >50% of partial ARMs of large PSD and multidomain (MD) grains are erased below $widetilde{H}$1, giving a low-field tail in the coercivity distribution. Natural pumices, granites, and oceanic basalts violated reciprocity, but lake sediments, gabbros, andesite, and red scoria had relatively small low-coercivity tails and are better candidates for paleointensity work. Using total ARM to simulate natural remanence, we carried out pseudo-Thellier paleointensity determinations for coarse PSD and MD grains. ARM demagnetization outweighed partial ARM acquisition at the same AF step, resulting in convex-down curves of ARM remaining versus partial ARM gained (pseudo-Arai plot). Pseudo-Arai plots predicted from experimentally determined distributions of blocking and unblocking fields agreed well with measured pseudo-Thellier results, in particular explaining convex-down MD curves.

BACKGROUND DATA FILES

Abstract

Keywords
Geomagnetism and Paleomagnetism, Rock and mineral magnetism, Geomagnetism and Paleomagnetism, Magnetic fabrics and anisotropy, Geomagnetism and Paleomagnetism, Paleointensity, Geomagnetism and Paleomagnetism, Instruments and techniques
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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