Evidence for large compositional ranges in coeval melts erupted from Kīlauea's summit reservoir: Chapter 7

Geophysical Monograph - 7
By: , and 
Edited by: Rebecca CareyValérie CayolMichael P. Poland, and Dominique Weis

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Abstract

Petrologic observations on Kīlauea's lavas include abundant microprobe analyses of glasses, which show the range of melts available in Kīlauea's summit reservoir over time. During the past two centuries, compositions of melts erupted within the caldera have been limited to MgO = 6.3–7.5 wt%. Extracaldera lavas of the 1959, 1971, and 1974 eruptions contain melts with up to 10.2, 8.9, and 9.2 wt% MgO, respectively, and the 1924 tephra contains juvenile Pele's tears with up to 9.1 wt% MgO. Melt compositions from explosive deposits at Kīlauea, including the Keanakāko‘i (A.D. 1500–1800), Kulanaokuaiki (A.D. 400–1000), and Pāhala (10–25 ka) tephra units, show large ranges of MgO contents. The range of melt MgO is 6.5–11.0 wt% for the Keanakāko‘i; the Kulanaokuaiki extends to 12.5% MgO and the Pāhala Ash includes rare shards with 13–14.5% MgO. The frequency distributions for MgO in the Keanakāko‘i and Kulanaokuaiki glasses are bimodal, suggesting preferential magma storage at two different depths. Kīlauea's summit reservoir contains melts ranging from 6.5 to at least 11.0 wt% MgO, and such melts were available for sampling near instantaneously and repeatedly over centuries. More magnesian melts are inferred to have risen directly from greater depth.

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Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Evidence for large compositional ranges in coeval melts erupted from Kīlauea's summit reservoir: Chapter 7
Series title Geophysical Monograph
Chapter 7
ISBN 978-1-118-87204-8
DOI 10.1002/9781118872079.ch7
Volume 208
Year Published 2015
Language English
Publisher American Geophysical Union; John Wiley & Sons
Publisher location Washington, D.C.
Contributing office(s) Eastern Geology and Paleoclimate Science Center
Description 21 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Hawaiian volcanoes: From source to surface
First page 125
Last page 145
Conference Title AGU Chapman Conference
Conference Location Waikoloa, Hawai'i
Conference Date August 20-24, 2012
Country United States
State Hawaii
Other Geospatial Kīlauea Volcano