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Intrusive dike complexes, cumulate cores, and the extrusive growth of Hawaiian volcanoes

Geophysical Research Letters

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Abstract

The Hawaiian Islands are the most geologically studied hot-spot islands in the world yet surprisingly, the only large-scale compilation of marine and land gravity data is more than 45 years old. Early surveys served as reconnaissance studies only, and detailed analyses of the crustal-density structure have been limited. Here we present a new chain-wide gravity compilation that incorporates historical island surveys, recently published work on the islands of Hawai‘i, Kaua‘i, and Ni‘ihau, and >122,000 km of newly compiled marine gravity data. Positive residual gravity anomalies reflect dense intrusive bodies, allowing us to locate current and former volcanic centers, major rift zones, and a previously suggested volcano on Ka‘ena Ridge. By inverting the residual gravity data, we generate a 3-D view of the dense, intrusive complexes and olivine-rich cumulate cores within individual volcanoes and rift zones. We find that the Hāna and Ka‘ena ridges are underlain by particularly high-density intrusive material (>2.85 g/cm3) not observed beneath other Hawaiian rift zones. Contrary to previous estimates, volcanoes along the chain are shown to be composed of a small proportion of intrusive material (<30% by volume), implying that the islands are predominately built extrusively.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Intrusive dike complexes, cumulate cores, and the extrusive growth of Hawaiian volcanoes
Series title:
Geophysical Research Letters
Volume
40
Issue:
13
Year Published:
2013
Language:
English
Publisher:
American Geophysical Union
Contributing office(s):
Volcano Science Center
Description:
7 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
3367
Last page:
3373
Country:
United States
State:
Hawai'i