HR: 0830h
AN: GP41A-05    [Abstracts]
TI: Rock Magnetic Properties of a Late Pleistocene Paleosol From Central Mexico
AU: * Rivas, J
EM: jorger@geofisica.unam.mx
AF: Universidad Nacional A. de Mexico Posgrado en Ciencias de la Tierra, Cd. Universitaria, Mexico, DF 04510 Mexico
AU: Ortega, B
EM: bortega@geofisica.unam.mx
AF: UNAM Instituto de Geofisica, Cd. Universitaria, Mexico, DF 04510 Mexico
AU: Solleiro, E
EM: solleiro@geologia.unam.mx
AF: UNAM Instituto de Geologia, Cd. Universitaria, Mexico, DF 04510 Mexico
AU: Sedov, S
EM: sergey@geologia.unam.mx
AF: UNAM Instituto de Geologia, Cd. Universitaria, Mexico, DF 04510 Mexico
AB: Rock-magnetic characteristics of a volcaniclastic-paleosol sequence from Tlaxcala, central Mexico, are analyzed in order to test the hypothesis of neo-formation of magnetic minerals as result of enhanced pedogenesis in A and B soil horizons, in comparison of the less affected or pedoganically unaltered parent material. Our study was carried out in a Chromic luvisol pedocomplex thought to have been formed during the last interglacial. The results show that, even if pedogenic fine grained magnetic minerals are present in the Bt horizons, these are destroyed in upper horizons, where pedogenesis has been more intense. Horizons A and E present the lowest magnetic susceptibility, however they also present the highest concentration of high coercivity hematite/goethite phases. In order to decode the paleoclimatic signal of this paleosol, rock-magnetism analysis in different pedogenetic materials as the soil itself, and cutans, cracks-filling material and humus found in soils, is in progress.
DE: 1512 Environmental magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly