Onset of rejuvenated-stage volcanism and the formation of Līhu‘e Basin - Kaua‘i events that occurred 3-4 million years ago: Chapter 6

Geophysical Monograph - 6
By: , and 
Edited by: Rebecca CareyValérie CayolMichael P. Poland, and Dominique Weis

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Abstract

For ocean-island volcanoes, an understanding of rejuvenated-stage volcanism requires knowing the age of onset, duration of the volcanic episode, and length of quiescence that preceded the rejuvenated pulse. On the Island of Kaua‘i, cuttings from two lava flows intercepted in the Hanamā‘ulu well (Līhu‘e basin) and assigned to the Kōloa Volcanics on basis of major-element, trace-element, and isotope geochemistry have yielded 40Ar/39Ar ages of 3.11 and 3.22 Ma. A deeper lava, with age 3.42 Ma, is tentatively assigned to the Kōloa. These ages partly fill a 1 Myr gap in the previously published ages for the Kōloa Volcanics and suggest that rejuvenated-stage volcanism on Kaua‘i has persisted for 3.2 Myr or longer. The quiescent period may have been as short as 0.2–0.3 Myr, possibly briefer.

The eastern third of Kaua‘i subsided as much as 1.3 km along an island-long north-south fault between 4.7 and 3.4 Myr ago. The fault marks a stunted episode of extension, inasmuch as displacement diminishes rapidly from the inland area north and south toward the coast and the fault lacks expression on the island's submarine flanks. The Līhu‘e basin formed sometime thereafter: The new ages are from lava flows that bracket shallow marine sediment, so the basin had subsided below sea level before 3 Ma. Though poorly constrained, rates of subsidence are in the range of those from Lāna‘i, which today sits at a distance from the hotspot that is similar to the paleogeographic position of Kaua‘i 3 Ma.

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Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Onset of rejuvenated-stage volcanism and the formation of Līhu‘e Basin - Kaua‘i events that occurred 3-4 million years ago: Chapter 6
Series title Geophysical Monograph
Chapter 6
ISBN 978-1-118-87204-8
DOI 10.1002/9781118872079.ch6
Volume 208
Year Published 2015
Language English
Publisher American Geophysical Union; John Wiley & Sons
Publisher location Washington, D.C.
Contributing office(s) Volcano Science Center
Description 20 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Hawaiian volcanoes: From source to surface
First page 105
Last page 124
Conference Title AGU Chapman Conference
Conference Location Waikoloa, Hawai'i
Conference Date August 20-24, 2012
Country United States
State Hawaii
Online Only (Y/N) N
Additional Online Files (Y/N) N