HR: 0830h
AN: S21E-0357    [PDF]
TI: Compressional Wave Velocities in Fe-Ni-Si Melts to $1650\deg$C: Contrasting Results Compared to Fe-Ni-S Melts
AU: * Manghnani, M H
EM: murli@hawaii.edu
AF: University of Hawaii, Hawaii Institute of Geophysics and Planetology, Honolulu, HI 96822 United States
AU: Fu, S S
EM: ssfu@SOEST.Hawaii.edu
AF: University of Hawaii, Hawaii Institute of Geophysics and Planetology, Honolulu, HI 96822 United States
AU: Secco, R A
EM: secco@uwo.ca
AF: University of Western Ontario, Department of Earth Sciences, London, ON N6A 5B7 Canada
AU: Nasch, P
EM: phillipe.nasch@hawaii.edu
AF: University of Hawaii, Hawaii Institute of Geophysics and Planetology, Honolulu, HI 96822 United States
AB: Using high-precision high temperature ultrasonic interferometric techniques we have measured V$_{P}$ in three molten Fe-Ni-Si alloys containing varying amounts of Fe (75-89 wt % Fe), 5 wt % Ni, and varying amounts of Si (6-20 wt %) in the temperature range $1190-1650\deg$C and in the frequency range 9-13 MHz. The temperature dependencies of V$_{P}$ for all the compositions are linear, and no dispersion is observed in the temperature and frequency ranges of the experiment. However, increasing amounts of Si cause a decrease in V$_{P}$ and an increase in the (dV$_{P}$/dT) value. The results for the Fe-Ni-Si melts are also compared with those previously obtained for Fe, Fe-Ni and Fe-Ni-S melts. Whereas in the Fe-Ni-S melts, addition of S was observed to cause anomalous elastic behavior (+dV$_{P}$/dT), the behavior in Fe-Ni-Si is normal. The results from these studies, although carried out at ambient pressure, may provide useful constraints on the composition of the Earth`s outer core.
DE: 7260 Theory and modeling
DE: 8124 Earth's interior--composition and state (old 8105)
DE: 8147 Planetary interiors (5430, 5724)
SC: Seismology [S]
MN: 2003 Fall Meeting