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New K-Ar ages for calculating end-of-shield extrusion rates at West Maui volcano, Hawaiian island chain

Bulletin of Volcanology

By:
, , and
DOI: 10.1007/s00445-006-0099-9

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Abstract

Thirty-seven new K-Ar ages from West Maui volcano, Hawai'i, are used to define the waning stages of shield growth and a brief episode of postshield volcanism. All but two samples from shield-stage strata have reversed polarity magnetization, so conceivably the exposed shield is not much older than the Olduvai Normal-Polarity subchron, or about 1.8 Ma. The oldest ages obtained are in the range 1.9-2.1 Ma but have large analytical error. Shield volcanism ended about 1.35 Ma, and postshield volcanism followed soon thereafter, persisting until about 1.2 Ma. Exposed shield-stage strata were emplaced at a rate of about 0.001 km3 per year, a rate smaller than historic Hawaiian magmatic rates by a factor of 100. Stratigraphic accumulation rates are similar to those measured previously at Wai'anae volcano (O'ahu) or the upper part of the Mauna Kea shield sequence (Hilo drill core, Hawai'i). These rates diminish sharply during the final 0.3-0.5 m.y. of the shield stage. Hawaiian shield volcanoes begin waning well before their last 0.5 m.y. of life, then end quickly, geologically speaking, if West Maui is representative. ?? Springer-Verlag 2006.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
New K-Ar ages for calculating end-of-shield extrusion rates at West Maui volcano, Hawaiian island chain
Series title:
Bulletin of Volcanology
DOI:
10.1007/s00445-006-0099-9
Volume
69
Issue:
6
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bulletin of Volcanology
First page:
627
Last page:
642