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G-Cubed: Geochemistry, Geophysics, Geosystems

 

Keywords

  • paleomagnetic secular variation
  • geocentric axial dipole
  • Trans-Mexican Volcanic Belt
  • San Luis Potosi
  • lava flows

Index Terms

  • Geomagnetism and Paleomagnetism: Paleomagnetic secular variation
  • Geomagnetism and Paleomagnetism: Paleomagnetism applied to tectonics: regional, global
  • Geomagnetism and Paleomagnetism: Time variations: secular and longer
Abstract
Cited By (8)
 

Abstract

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, VOL. 6, Q07H19, 19 PP., 2005
doi:10.1029/2004GC000871 [Citation]

Paleosecular variation and time-averaged field recorded in late Pliocene–Holocene lava flows from Mexico

V. Mejia

Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, Florida, P.O. Box 112120, 32611-2120, USA

H. Böhnel

Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, 76230, Mexico

N. D. Opdyke

Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, Florida, P.O. Box 112120, 32611-2120, USA

M. A. Ortega-Rivera

Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, 76230, Mexico

J. K. W. Lee

Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario, K7L 3N6 Canada

J. J. Aranda-Gomez

Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, 76230, Mexico

This paper presents results from 13 paleomagnetic sites from an area west of Mexico City and 7 sites from an area of dispersed monogenetic volcanism in the state of San Luis Potosi, accompanied by seven 40Ar/39Ar radiometric dates. An analysis of secular variation and time-averaged paleomagnetic field in the Trans-Mexican Volcanic Belt (TMVB), using compiled data both newly obtained and from the literature, is presented. Interpretation can best be constrained after excluding from the data set sites that appear to be tectonically affected. The selected data include 187 sites of late Pliocene-Holocene age. The mean direction among these sites is Dec = 358.8°, Inc = 31.6°, α95 = 2.0°, k = 29. This direction does not overlap the expected geocentric axial dipole (GAD) but is consistent with a GAD plus a 5% quadrupole. The virtual geomagnetic pole scatter of this group of sites (12.7°, with lower and upper 95% confidence limits of 11.9° and 14.1°) is consistent with the value expected from Model G (13.6°).

Received 27 October 2004; accepted 9 May 2005; published 21 July 2005.

Citation: Mejia, V., H. Böhnel, N. D. Opdyke, M. A. Ortega-Rivera, J. K. W. Lee, and J. J. Aranda-Gomez (2005), Paleosecular variation and time-averaged field recorded in late Pliocene–Holocene lava flows from Mexico, Geochem. Geophys. Geosyst., 6, Q07H19, doi:10.1029/2004GC000871.

Cited By

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