Confounding influence of magnetic fabric on sedimentary records of a field reversal

Xavier Quidelleur, John Holt, Jean Pierre Valet

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

RECENT compilations of geomagnetic reversal records1–8 have generated a controversy as to whether the geomagnetic field is geographically biased during polarity transitions. At present there is general agreement that the virtual geomagnetic poles recorded from Cenozoic sediments preferentially lie over the Americas (or the antipodal longitude), yet such a preference is not statistically established7, 9. However, it is intriguing that the claimed preferred paths lie 90Ŷ away from the site longitude4, 9. Although this may be partly inherent in the very poor geographical distribution of the sites, we prefer not to rely on fortuitous coincidences. Several authors have argued that sedimentary palaeomagnetic records may be modified by artefacts linked to the acquisition of magnetization10–13. Here we report that in two sedimentary records of the Upper Olduvai reversal from Confidence Hills, California, the declinations of the remanent magnetization recorded during the reversal are similar to the directions of the maximum horizontal axes of the ellipsoids of magnetic anisotropy. This supports the idea that, at times of low geomagnetic intensity (such as during a reversal), factors other than the geomagnetic field influence the orientation of elongated grains.

Original languageEnglish (US)
Pages (from-to)246-249
Number of pages4
JournalNature
Volume374
Issue number6519
DOIs
StatePublished - Mar 16 1995
Externally publishedYes

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Confounding influence of magnetic fabric on sedimentary records of a field reversal'. Together they form a unique fingerprint.

  • Cite this