HR: 0800h
AN: GP11C-0840    [Abstracts]
TI: Preliminary Microwave Palaeointensity Results From the Tatara-San Pedro Volcanic Complex, Chile - Intensity Variation Through the Matuyama-Brunhes Transition?
AU: * Gratton, M N
EM: gratton@liv.ac.uk
AF: Geomagnetism Laboratory, Univ. of Liverpool, Liverpool, L69 7ZE United Kingdom
AU: Brown, L
EM: lbrown@geo.umass.edu
AF: Dept. of Geosciences, Univ. of Massachusetts, Amherst, MA MA 01003 United States
AU: Shaw, J
EM: shaw@liv.ac.uk
AF: Geomagnetism Laboratory, Univ. of Liverpool, Liverpool, L69 7ZE United Kingdom
AB: A sequence of lavas from the Tatara-San Pedro volcanic complex (Andes, Chile) recording transitional directions has been dated and palaeomagnetic directions obtained (Brown et al., in press. J. Geophys. Res.). Ar/Ar dates from this study suggest this sequence records an event preceding the main Matuyama-Brunhes transition (MBT), though some normal polarity directions are recorded from the upper part of the lava sequence. Microwave palaeointensity determinations at the Liverpool University Geomagnetism Laboratory have been made to ascertain whether these normal polarities are related to the pre-cursor event or represent the end of the main MBT. Preliminary results yielding high intensity values from the normal polarity flows (up to ten times that of the transitional field intensity) suggest that the post-reversal field is recorded in these flows.
DE: 1521 Paleointensity
DE: 1535 Reversals (process, timescale, magnetostratigraphy)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting