Paleomagnetic intensity data as a time sequence; opening a window into dynamics of Earth's fluid core?

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doi: 10.1029/145GM18
Author(s): Baker, Ross; Aldridge, Keith
Author Affiliation(s): Primary:
York University, Physics and Astronomy, Toronto, ON, Canada
Volume Title: Timescales of the paleomagnetic field
Volume Author(s): Channell, James E. T., editor; Kent, Dennis V.; Lowrie, William; Meert, Joseph G.
Source: Timescales of the paleomagnetic field, edited by James E. T. Channell, Dennis V. Kent, William Lowrie and Joseph G. Meert. Geophysical Monograph, Vol.145, p.245-254. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0065-8448. ISBN: 978-1-118-66585-5 CODEN: GPMGAD
Note: In English with English summary. 25 refs.; illus., incl. 1 table
Summary: Paleomagnetic intensity data from single (ODP 983) and composite (NAPIS-75) oceanic cores are analyzed for evidence of a rotating parametric instability (RPI) in Earth's fluid outer core. RPI, observed in laboratory experiments for over three decades, in Earth's core would be a resonant triad of two inertial modes coupled through straining of the core-mantle boundary. Small deformations in both amplitude, due to the semi-diurnal tide, and direction, from precession, produce growth of the instability on a geomagnetic time scale. Just as in laboratory observations of the RPI, alternating sequences of growth and decay continue at irregular intervals while straining is maintained and as long as the dissipation is sufficiently small. Presented here as e-folding times, decays show much less variance than growths while both are geophysically plausible. Combining growths and decays using linear stability theory yields e-folding times with reduced variance for the single and composite cores.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Atlantic Ocean; Cenozoic; Core; Crust; Fluid phase; Leg 162; Magnetic field; Magnetic intensity; Magnetization; Mathematical methods; Matuyama Chron; North Atlantic; ODP Site 983; Ocean Drilling Program; Oceanic crust; Paleomagnetism; Properties; Upper Cenozoic
Coordinates: N602412 N602412 W0233826 W0233826
Record ID: 2007019839
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