Magma transport at Hawaii; inferences based on igneous thermobarometry

Pyroxene + liquid equilibrium in Hawaiian lavas occurs at a range of pressures for each volcano. Ranges are systematic and may be related to the stage of development of the magma conduit system. Kilauea, which is in its shield-building phase, yields relatively shallow storage estimates. Loihi and Ma...

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Bibliographic Details
Published in:Geology (Boulder) 1997-01, Vol.25 (1), p.69-72
Main Author: Putirka, Keith
Format: Article
Language:English
Subjects:
crust
East Pacific
East Pacific Ocean Islands
geologic barometry
geologic thermometry
Geology
Hawaii
Hawaii County Hawaii
Hawaii Island
igneous and metamorphic rocks
igneous rocks
Kilauea
Lava
lithosphere
Loihi Seamount
magma chambers
magma transport
magmas
Mauna Kea
mechanical properties
North Pacific
Northeast Pacific
Oceania
P-T conditions
Pacific Ocean
Petrology
Polynesia
transport
United States
volcanic rocks
Volcanoes
volcanology
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Summary:Pyroxene + liquid equilibrium in Hawaiian lavas occurs at a range of pressures for each volcano. Ranges are systematic and may be related to the stage of development of the magma conduit system. Kilauea, which is in its shield-building phase, yields relatively shallow storage estimates. Loihi and Mauna Kea, which are in the early and late stages of volcano growth, respectively, yield deeper storage estimates. Shallowest depth estimates at Loihi and Mauna Kea are similar to estimates of elastic plate thickness, suggesting that the mechanical behavior of the lithosphere, rather than density contrasts at the Moho, regulates magma delivery. Apparently, a large increase in fracture energy below the brittle-ductile transition inhibits transport at depth, whereas magma transport by fracture propagation is rapid through the brittle lithosphere. Some shallow depth estimates at Kilauea support the hypothesis that the strength of the unbuttressed southeast flank influences magma storage. Kilauea transport depths correlate with an eruption sequence, which illustrates a top-to-bottom emptying of the conduit system. Successively deeper reservoirs at Kilauea were tapped within 300 days, indicating that magma is stored at a range of depths, including in the mantle, rather than at a single level within the lithosphere.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1997)025<0069:MTAHIB>2.3.CO;2