New Zealand Journal of Geology and Geophysics abstracts
Short communication
Temporally linked volcanic centres in the Auckland Volcanic Field
John Cassidy
Corinne A. Locke
Department of Geology
University of Auckland
Private Bag 92 019
Auckland, New Zealand
Abstract New aeromagnetic data from the Auckland Volcanic
Field reveal negative magnetic anomalies over Taylor Hill and Mt St John
volcanoes which are interpreted as resulting from anomalous remanent magnetisation
directions. These anomalies are comparable in character to those occurring
over three volcanoes in the southern part of the field that record coincident
anomalous directions associated with a geomagnetic excursion. Since rates
of change of the geomagnetic field may be rapid during such excursions, and
their duration short, a strong temporal link is implied between these five
separate volcanic centres, which are geographically spread throughout the
Auckland field. Even assuming normal rates of secular variation, the total
time period for these eruptions might be only several hundred years, which
suggests a recurrence interval for these volcanoes that is much less than
any currently estimated for the field.
Keywords Auckland Volcanic Field; aeromagnetic anomalies;
geomagnetic excursion; Taylor Hill; Mt St John; volcanic hazard
G03028; Received 26 August 2003; accepted 15 December 2003; Online publication
date 20 May 2004
New Zealand Journal of Geology & Geophysics, 2004, Vol. 47: 287–290
0028–8306/04/4702–0287 © The Royal Society of New Zealand 2004
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