HR: 1340h
AN: GP13A-0038    [Abstracts]
TI: Magnetomineralogical Investigations Of Yaxcopoil-1 Drill Core Samples
AU: * Elbra, T
EM: tiiu.elbra@helsinki.fi
AF: Division of Geophysics, University of Helsinki, P.O. Box 64, Helsinki, 00014 Finland
AU: Pesonen, L J
EM: lauri.pesonen@helsinki.fi
AF: Division of Geophysics, University of Helsinki, P.O. Box 64, Helsinki, 00014 Finland
AB: We are presenting magnetomineralogical data from Yaxcopoil-1 drill core, Chicxulub impact crater. Several paleomagnetic and thermo-magnetic measurements (thermal behavior of magnetic susceptibility) were carried out in order to detect magnetic components and their carriers. In order to determine possible magnetic mineralogy changes due to heating of the samples the hysteresis measurements where carried out before and after heating cycle. Most of pre- and post impact samples show before heating dominant para- or diamagnetic behavior on hysteresis curve. When this component is subtracted, weak signal of ferromagnetic component can be observed. Thermal behavior of magnetic susceptibility shows that the ferromagnetic component is probably titanomagnetite. After heating, hysteresis loop shows increase in ferromagnetic signal and on cooling magnetic susceptibility curve the newly produced magnetite is identified. Thermal behavior of magnetic susceptibility of non-heated impact layer samples indicates mostly complex mixture with dominant contribution of titanomagnetite, magnetite and pyrrhotite. The hysteresis data show pseudo-single and multi-domain behavior of (titano-) magnetite. In contrast to pre- and post impact samples there are no significant mineralogical changes observed in impact layer samples. This can be the result of impact related thermal metamorphism of magnetic phase.
DE: 1540 Rock and mineral magnetism
DE: 5109 Magnetic and electrical properties (0925)
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005