HR: 17:35h
AN: GP44A-06    [Abstracts]
TI: Towards the establishment of an archeointensity master curve for Mesoamerica
AU: * Morales, J
EM: jmorales@geofisica.unam.mx
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria s/n, Mexico, 04510, Mexico
AU: Gogichaisvili, A
EM: avto@geofisica.unam.mx
AF: Laboratorio Interinstitucional de Magnetismo Natural, Coeneo, Michoacan, Mexico
AU: Acosta, G
AF: Instituto de Investigaciones Antropologicas, UNAM, Ciudad Universitaria s/n, Mexico, 04510, Mexico
AU: Gonzales, T
AF: Instituto de Geofisica, UNAM, Ciudad Universitaria s/n, Mexico, 04510, Mexico
AB: We present new rock-magnetic and archaeointensity results of some pre-Columbian potteries found at archaeological caves in Chiapas, Southeast Mexico. The ceramics studied consist mostly of tiles of different archaeological artifacts. Their archeological ages cover mainly two ranges: from 550-250 BC and from 100-500 AD. ‘Rock-magnetic' experiments which included susceptibility vs. temperature and hysteresis measurements were used to select magnetically stable and suitable material for Thellier absolute intensity determinations. Six out of thirteen archaeological tiles, which showed no evidence of strong secondary components and presenting almost reversible susceptibility curves, were selected for archeointensity studies. Each of these tiles were further divided into at least seven fragments and then set in salt (NaCl) pellets in order to treat them as standard paleomagnetic cores. Magnetization per unit volume of ‘blank' pellets is negligible with respect to that of ceramic samples. Archeointensity experiments were carried out using the Coe version of the Thellier method. Cooling rate and anisotropy effects were investigated on each sample. Thellier experiments yielded unusually high success rate and data obtained are of excellent technical quality, attested by reasonably high Coe's factors. This pioneering study proves the usefulness of Mesoamerican ceramics for archeointensity studies and opens new perspectives towards the establishment of a reference intensity variation curve for the region.
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1503 Archeomagnetism
DE: 1519 Magnetic mineralogy and petrology
DE: 1521 Paleointensity
DE: 1522 Paleomagnetic secular variation
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly