HR: 16:45h
AN: GP34A-06    [Abstracts]
TI: On the importance of cooling rate correction in volcanic rocks: case study of a single Xitle lava flow (Central Mexico)
AU: * Morales, J
EM: jmorales@geofisica.unam.mx
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria s/n, Mexico, 04510 Mexico
AU: Gogichaishvili, A
EM: avto@geofisica.unam.mx
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria s/n, Mexico, 04510 Mexico
AU: Urrutia Fucugauchi, J
EM: juf@geofisica.unam.mx
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria s/n, Mexico, 04510 Mexico
AB: Many studies have been devoted to understand the significant variation of absolute Thellier paleointensity often observed within a single lava flow. Any attempts however, to find possible correlation between these variations and some physical/magnetic parameters has been unsatisfactory. Up to now, any possible explanations are mainly based on distinct oxidation states of opaque minerals throughout the profile or with the chemical alteration of the sample during the heating. Apart from archaeomagnetic investigations, the effect of cooling rate upon acquisition of thermoremanent magnetization (TRM) has not been taking into account. Systematic scatter and overestimating of PI values obtained in a single lava flow from Xitle volcano is drastically reduced when using cooling rate correction to raw selected data. Moreover, precision of individual determinations is substantially increased. Cooling rate effect upon acquisition of TRM in volcanic rocks seems to be as critical as in archaeomagnetic investigations.
DE: 1521 Paleointensity
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly