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On the equatorial virtual pole distribution
Earth, Planets and Space volume 56, pages 589–598 (2004)
Abstract
In this paper, we show that the Virtual Geomagnetic Pole (VGP) distribution used in paleomagnetic studies is only one of the 2D spherical projections of a 3D paleomagnetic directional data set. Therefore, in principle, the VGP distribution does not by itself completely represent the paleomagnetic directional data set. We suggest that it is necessary to include in the analyses another 2D spherical projection of a 3D paleomagnetic directional data set—the Equatorial Virtual Pole (EVP) distribution. The EVP is defined as the point 90° from the VGP along the great circle through the VGP and the site. The VGP and EVP distributions represent different aspects of the directional data sets and information not carried in the VGP distribution is carried by the EVP distribution. Ideal VGP and EVP distributions depict different aspects of the characteristics of the geomagnetic field as such that, while the VGPs tend to distribute symmetrically around the regions where the field is perpendicular to the earth’s surface, the EVPs concentrate about the nodal or null flux lines.
References
Clement, B., Longitudinal distribution of Brunhes-Matuyama transitiona VGPs, EOS Trans. AGU, 70, 1073, 1989.
Courtillot, V., J.-P. Valet, G. Hulot, and J. L. Le Mouël, The Earth’s magnetic field: Which symmetry, EOS Trans. AGU, 73, 337, 340–342, 1992.
Gubbins, D. and P. Kelly, On the analysis of paleomagnetic secular variation, J. Geophys. Res., 100, 14,955–14,964, 1995.
Hoffman, K. A., Transitional paleomagnetic field behaviour: Preferred paths or patches, Surv. Geophys., 17, 207–211, 1996.
Hatakeyama, T. and M. Kono, Geomagnetic field model for the last 5 My: time-averaged field and secular variation, Phys. Earth Planet. Inter., 133, 181–215, 2002.
Johnson, C. L. and C. G. Constable, The time-averaged field as recorded by lava flows over the past 5 Myr years, Geophys. J. Int., 122, 489–519, 1995.
Laj, C. A., A. Mazaud, R. Weeks, M. Fuller, and E. Herrero-Bervera, Geomagnetic Reversal Paths, Nature, 351, 447, 1991.
Merrill, R. T., E. W. McElhinny, and P. L. McFadden, The Magnetic Field of the Earth, Academic Press, 1996.
Prevot, M. and P. Camps, Absence of preferred longitude sectors for poles from volcanic records of geomagnetic reversals, Nature, 366, 53–57, 1993.
Quidelleur, X., J.-P. Valet, V. Courtillot, and G. Hulot, Long term geometry of the geomagnetic field for the last five million years, Geophys. Res. Lett., 21, 1639–1642, 1994.
Shao, J.-C, M. Fuller, T. Tanimoto, J. R. Dunn, and D. B. Stone, Spherical Harmonic analysis of Paleomagnetic Data: The time-averaged geomagnetic field for the past 5 Myr and the Matuyama-Brunhes Reversal, J. Geophys. Res., 104, 5015–5030, 1999.
Shao, J.-C. and M. Fuller, Hemispherical Asymmetry in reversal Transition Fields, IUGG XXII, Abstracts, A292, 1999.
Shao, J.-C. and Y. Hamano, Inferences of the earth’s magnetic field from surface directional data, pp. 171, Proceedings of the OHP/ION Joint Symposium, 2001.
Shao, J.-C, Y. Hamano, M. Bevis, and M. Fuller, A representation function for the point distribution on the unit sphere—with applications to the analyses on the distribution of the virtual geomagnetic poles, Earth Planets Space, 55(7), 395–404, 2003.
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Shao, JC., Fuller, M. & Hamano, Y. On the equatorial virtual pole distribution. Earth Planet Sp 56, 589–598 (2004). https://doi.org/10.1186/BF03352519
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DOI: https://doi.org/10.1186/BF03352519