HR: 17:45h
AN: GP24A-08    [Abstracts]
TI: Prospects for Resolving Short-term Variations in the Paleomagnetic Dipole Moment
AU: * Constable, C
EM: cconstable@ucsd.edu
AF: University of California at San Diego, IGPP, SIO, La Jolla, CA 92093-0225 United States
AU: Korte, M
EM: monika@gfz-potsdam.de
AF: GeoForschungs Zentrum, Telegrafenberg, Potsdam, 14473 Germany
AB: Variations in dipole moment can only be inferred from direct measurements since 1840. Prior to that they must be estimated from paleofield observations using time averages of virtual axial dipole moments or the temporally varying dipole moments from time-varying paleofield models like CALS7K.2 which extends to 7~ka. The rates of change in geomagnetic dipole moment inferred from direct observation since 1840, are as high as 10% per century, and for CALS7K.2 the rates have been as high or higher. However, the temporal resolution in current paleofield models can be no better than 100 years, and is likely to be considerably worse in some time intervals. Changes on time scales intermediate between the historical and centennial scales may reflect important geomagnetic processes. They could also play a role in the study of solar climate connections through temporal variations in cosmogenic nuclides which are complicated by the fact that in general production rates depend on both solar flux and geomagnetic dipole moment variations. The dipole moment from CALS7K.2 changes on a broad range of time scales, and thus dipole moment variations are likely to influence attempts to estimate centennial to millennial scale changes in solar flux. The primary factor limiting resolution in short term fluctuations of the dipole moment is dating paleomagnetic records. We evaluate the temporal resolution for CALS7K.2 and explore the possibility of developing high resolution dipole moment estimates from selected high quality records.
DE: 1503 Archeomagnetism
DE: 1522 Paleomagnetic secular variation
DE: 1560 Time variations: secular and longer
DE: 7536 Solar activity cycle (2162)
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005