The myth of the Pacific dipole window

Details The myth of the Pacific dipole window The myth of the Pacific dipole window

Sep 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996e%26psl.143...13m&link_type=abstract

Earth and Planetary Science Letters, Volume 143, Issue 1-4, p. 13-22.

Mathematics

Logic

31

Scientific paper

The angular dispersion of virtual geomagnetic poles (VGP) from lava flows is often cited as having been anomalously low in the Pacific during the Brunhes epoch because the dispersion from Hawaiian lavas is said to be much lower than measured elsewhere. This led to the concept of the Pacific dipole window or Pacific non-dipole low. Because lavas tend to be erupted in bursts of activity, many of the Hawaiian data are serially correlated and thus cannot necessarily be treated as independent observations. Geochronological controls, as are available for Hawaii, have been used in a previous analysis to thin the data to try to avoid repeated sampling of the same geomagnetic field. Unfortunately, in that analysis the angular dispersion of VGPs was calculated about the mean VGP instead of about the spin axis, and thus underestimated the dispersion. We have therefore reanalyzed the relevant data using the following criteria. (1) Only those lavas with α95 < 10° have been considered. (2) A latitude-dependent cut-off angle is used to eliminate those vectors that are not part of the normal secular variation. (3) We have developed a statistical method to rationalise those flows that have repeatedly sampled the same geomagnetic field vector, because suitable geochronological controls are rarely available. Application of this new method to the Hawaiian data shows excellent agreement with the results from using geochronological controls. Where possible we have therefore included this method in our overall analysis. As expected, the resulting global data are compatible with a Fisher distribution about the spin axis. Brunhes age data from Hawaii (N = 96 independent measurements) give a VGP angular dispersion about the spin axis of SF = 12.4°, and for the Pacific region as a wholeSF = 12.5° (N = 190) between latitudes 15° and 30° (north or south). These values are the same as SF = 12.4° (N = 160) calculated for the rest of the world in the same latitude range. This clearly demonstrates that the hypothesis of the Pacific dipole window may confidently be rejected.

Affiliated with

Also associated with

No associations

Rating

The myth of the Pacific dipole window does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The myth of the Pacific dipole window, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The myth of the Pacific dipole window will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1462612