Weaker axially dipolar time-averaged paleomagnetic field based on multidomain-corrected paleointensities from Galapagos lavas

Huapei Wang, Dennis V. Kent, Pierre Rochette

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The geomagnetic field is predominantly dipolar today, and highfidelity paleomagnetic mean directions from all over the globe strongly support the geocentric axial dipole (GAD) hypothesis for the past few million years. However, the bulk of paleointensity data fails to coincide with the axial dipole prediction of a factor-of-2 equator-to-pole increase in mean field strength, leaving the core dynamo process an enigma. Here, we obtain a multidomain-corrected PliocenëCPleistocene average paleointensity of 21.6-11.0 T recorded by 27 lava flows from the Galapagos Archipelago near the Equator. Our new result in conjunction with a published comprehensive study of single-domainCbehaved paleointensities from Antarctica (33.4-13.9 T) that also correspond to GAD directions suggests that the overall average paleomagnetic field over the past few million years has indeed been dominantly dipolar in intensity yet only ∼60% of the present-day field strength, with a long-term average virtual axial dipole magnetic moment of the Earth of only 4.9 2.4 1022 Am2.

Original languageEnglish (US)
Pages (from-to)15036-15041
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number49
DOIs
StatePublished - Dec 8 2015

All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Geomagnetism
  • Multidomain correction
  • Paleomagnetism
  • Thellier paleointensity experiment
  • Time-averaged dipole field

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