Broad trends in geomagnetic paleointensity on Hawaii during Holocene time

Journal of Geophysical Research B: Solid Earth
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Abstract

Paleointensity determinations have been obtained from 22 basaltic lava flows on the island of Hawaii using the Thelliers' method. Radiocarbon dating indicates that these flows erupted at intervals ranging from about 200 to 1000 years, and results of the experiments provide an estimate of broad trends in geomagnetic paleointensity during Holocene time in the vicinity of Hawaii. Most of the samples were obtained from quickly cooled flow margins and, as a consequence, typically contain two titanomagnetite populations. Only two of the 79 samples analyzed failed to yield an estimate of the paleofield, demonstrating that paleointensities can be obtained from such samples if carefully selected. Virtual dipole moments calculated for the flows are compared with a published curve of dipole field intensity that was constructed using worldwide archeomagnetic data. The large nondipole fields that were previously postulated for the vicinity of Hawaii are confirmed, and the present data indicate that they were present from about 5000 years B.P. to perhaps as recently as the past 200 years. The data indicate, however, that these nondipole sources must have been virtually absent between about 12,000 and 5000 years B.P. as they are at the present time.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Broad trends in geomagnetic paleointensity on Hawaii during Holocene time
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/93JB00024
Volume 98
Issue B5
Year Published 1993
Language English
Publisher AGU
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 18 p.
First page 7959
Last page 7976
Country United States
State Hawaii