Geophyical Research Letters (American Geophysical Union)
Rocks at depth in the crust acquire a viscous (i.e., time-dependent) magnetization under the pressure-temperature conditions at which they reside. There have been numerous studies on the effect of temperature on viscous magnetization but little work has been performed on the effect of hydrostatic pressure. We have studied viscous remanent magnetization at 22°C in a 0.1 mT field at 0.1 and 100 MPa for natural and synthetic multidomain magnetite. The viscous remanent magnetization was found to increase nearly linearly with log(time) at both pressures. There was little change in the rate of viscous acquisition between 0.1 and 100 MPa over the multidomain grain size range studied. Thus for rocks buried at depth in the earth the enhancement of magnetic viscosity by thermal fluctuations will dominate over effects due to hydrostatic pressure.
Kelso, P. R. and S. K. Banerjee (1995). "The effect of hydrostatic pressure on viscous remanent magnetization." Geophysical Research Letters 22: 1953-1956.
This project was supported by NASA grant NGT-50421 and a doctoral dissertation fellowship from the University of Minnesota. We wish to thank the
Institute for Rock Magnetism (IRM) in Minneapolis for the use of its facilities. The IRM is funded by the Keck Foundation, the National Science Foundation, and the University of Minnesota. This is IRM contribution number 9402.
Kelso, Paul; Banerjee, Subir.
Effect of hydrostatic pressure on viscous remanent magnetization in magnetite-bearing specimens.
Geophyical Research Letters (American Geophysical Union).
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