HR: 11:20h
AN: U52B-04    [Abstracts]
TI: Magnetite and Native Gold Nanoparticles: Relation with Hydrothermal-Sedimentary Exhalative Environments in Iron-Ore Deposit
AU: * Rivas-Sanchez, M
EM: mlrivas@geofisica.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, UNAM, Coyoacan, Mexico, 04510, Mexico
AU: Alva-Valdivia, L
EM: lalva@geofisica.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, UNAM, Coyoacan, Mexico, 04510, Mexico
AU: Urrutia-Fucugauchi, J
EM: juf@geofisica.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, UNAM, Coyoacan, Mexico, 04510, Mexico
AU: Arenas-Alatorre, J
EM: jarenas@fisica.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Instituto de Fisica, UNAM, Coyoacan, Mexico, 04510, Mexico
AU: Ruiz-Sandoval, M
EM: mruiz@cmbjpc.com.mx
AF: Consorcio Minero Benito Juarez Peña Colorada, Avenida del Trabajo No. 1000, Manzanillo, Colima, Colima, Mexico
AU: Ramos-Molina, M
EM: aramos@cmbjpc.com.mx
AF: Consorcio Minero Benito Juarez Peña Colorada, Avenida del Trabajo No. 1000, Manzanillo, Colima, Colima, Mexico
AB: We report for the first time on the finding of magnetite and native gold nanoparticles in an iron-ore deposit. Initial results contribute to understanding the peculiar behaviour and distinctive physical, chemical and magnetic characteristics of the nanoparticles in the iron ore. Study of the natural magnetite nanoparticles provides information on the grain-size effects in their properties and in their nanomineral phases of transformation from temperature effects. This is used to develop a model of the genetic and environmental conditions of nanoparticles formation. Crystallographic studies in magnetite nanoparticles and berthierine were performed by high resolution TEM, and by X-ray diffraction, differential and gravimetric thermal analysis and Mössbauer spectroscopy. We observe magnetite nanoparticles semi-spherical shapes from 2 to 14 nm included in berthierine; continuous formation magnetite nanoparticles for nucleation in the hydrothermal-diagenetic processes provoks aggregates of nanoparticles associated to berthierine, both minerals are genetic indicators of hydrothermal-sedimentary exhalative environments. In our study, we found one locality of berthierine and chamosite in the Peña Colorada deposit. Results permit to observe in the magnetite nanoparticles a high heating resistance, high Curie temperature, Tc = 690 oC d high frequency dependent factor. Mössbauer spectroscophy shows a doublet of distinctive nanophases of Fe2 and Fe3 resulting from magnetite with superpragmatic behaviour.
DE: 3600 MINERALOGY AND PETROLOGY
DE: 3625 Petrography, microstructures, and textures
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 3999 General or miscellaneous
DE: 5112 Microstructure
SC: Union [U]
MN: 2007 Joint Assembly