HR: 1340h
AN: GP53C-1372    [Abstracts]
TI: Determining Archaeointensity From Anisotropic Ceramics
AU: * Suttie, N
EM: n.suttie@liverpool.ac.uk
AF: University of Liverpool, Geomagnetism Laboratory, Oliver Lodge Labs, Liverpool, L687ZE, United Kingdom
AB: Archaeological ceramics provide a convenient source of information regarding the past magnetic field intensity, but they are often strongly anisotropic. The remanent magnetism is not parallel to the ancient field but lies towards the preferred direction of magnetization. If the laboratory field is applied parallel to the NRM, the TRM gained will not be in the direction of the NRM, and will have a different magnitude than the TRM that would have been gained if the laboratory field had been applied in the same direction as the ancient field. This can lead to erroneous values of archaeointensity. A correction can be made by determining the tensor of anisotropy of thermoremanence but if the laboratory field can always be applied in a direction that produces a TRM parallel to the NRM, no correction should be needed. At the University of Liverpool, the microwave system used for archaeointensity measurement employs an automated sample carriage and 3 axis programmable applied field coils that allow the applied field and the resulting sample moment to be determined with high precision, so that by careful control of the applied field direction we can produce a TRM nearly parallel to the NRM. If this is done no anisotropy correction is needed.
DE: 1503 Archeomagnetism
DE: 1518 Magnetic fabrics and anisotropy
DE: 1521 Paleointensity
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting