dc.contributor.author |
Cocker, Kate |
|
dc.contributor.author |
Shane, Phil |
|
dc.contributor.author |
Cronin, Shane |
|
dc.contributor.author |
Stirling, Claudine |
|
dc.contributor.author |
Reid, Malcolm |
|
dc.date.accessioned |
2023-10-02T23:02:16Z |
|
dc.date.available |
2023-10-02T23:02:16Z |
|
dc.date.issued |
2022-10 |
|
dc.identifier.citation |
(2022). G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences, 23(10), Article ARTN e2022GC010589. |
|
dc.identifier.issn |
1525-2027 |
|
dc.identifier.uri |
https://hdl.handle.net/2292/66030 |
|
dc.description.abstract |
Many andesites erupted at arc volcanoes are the products of magma mixing, and this process could be important in triggering their eruption. Throughout the life of Ngauruhoe volcano (∼2.5 ka), erupted andesites lack macroscopic enclaves or lithological features of mingled magma. However, intricate microscopic features of magma mixing and mingling occur. Plagioclase phenocrysts have a wide range of textures. Their diverse <jats:sup>87</jats:sup>Sr/<jats:sup>86</jats:sup>Sr values (0.7039–0.7060) are mostly discordant with the groundmass (∼80%), and many phenocrysts (>40%) are isotopically zoned. Resorbed calcic cores overgrown by sodic rims are common, and record a gradient of increasing <jats:sup>87</jats:sup>Sr/<jats:sup>86</jats:sup>Sr, the result of progressive mixing with a radiogenic melt. Clinopyroxenes and orthopyroxenes have relict cores that nucleated in silicic melts (∼Mg# 30–40), and their rims record cycles of growth in mafic melts (∼Mg# 50–60). Olivine‐bearing, mafic glassy blebs (mostly <500 μm) that occur in the groundmass are the relicts of the intruding magma that disintegrated during the mixing/mingling process, and liberated crystals. Thus, some andesites that lack banding or enclaves are in fact the product of thorough mixing of contrasting magmas. This may require a regime of frequent intrusion leading to hybridization with the stagnant resident magma. Thus, frequent eruptions during Ngauruhoe's historic episode ending in 1975 CE are likely to have been a manifestation of frequent replenishment. A mixing origin for intermediate rocks at volcanic arcs is likely to be more prevalent than previously documented: further evidence for the rarity of andesite liquids in such settings. |
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dc.language |
en |
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dc.publisher |
American Geophysical Union (AGU) |
|
dc.relation.ispartofseries |
Geochemistry Geophysics Geosystems |
|
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
|
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
|
dc.rights.uri |
https://creativecommons.org/licenses/by/4.0/ |
|
dc.subject |
37 Earth Sciences |
|
dc.subject |
3703 Geochemistry |
|
dc.subject |
3705 Geology |
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dc.subject |
3706 Geophysics |
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dc.subject |
Science & Technology |
|
dc.subject |
Physical Sciences |
|
dc.subject |
Geochemistry & Geophysics |
|
dc.subject |
andesite |
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dc.subject |
magma |
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dc.subject |
plagioclase |
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dc.subject |
Sr isotopes |
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dc.subject |
subduction |
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dc.subject |
volcano |
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dc.subject |
NEW-ZEALAND |
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dc.subject |
ZONED CLINOPYROXENE |
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dc.subject |
ERUPTION TRIGGERS |
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dc.subject |
RUAPEHU VOLCANO |
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dc.subject |
ISLAND-ARC |
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dc.subject |
PETROGENESIS |
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dc.subject |
EVOLUTION |
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dc.subject |
ORIGIN |
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dc.subject |
BASALT |
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dc.subject |
02 Physical Sciences |
|
dc.subject |
04 Earth Sciences |
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dc.subject |
51 Physical sciences |
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dc.title |
A History of Andesite Production via Magma Mixing and Mingling Revealed Microscopically at Ngauruhoe Volcano |
|
dc.type |
Journal Article |
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dc.identifier.doi |
10.1029/2022gc010589 |
|
pubs.issue |
10 |
|
pubs.volume |
23 |
|
dc.date.updated |
2023-09-12T21:44:38Z |
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dc.rights.holder |
Copyright: The authors |
en |
pubs.publication-status |
Published |
|
dc.rights.accessrights |
http://purl.org/eprint/accessRights/OpenAccess |
en |
pubs.subtype |
Article |
|
pubs.subtype |
Journal |
|
pubs.elements-id |
921283 |
|
pubs.org-id |
Science |
|
pubs.org-id |
School of Environment |
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dc.identifier.eissn |
1525-2027 |
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pubs.number |
ARTN e2022GC010589 |
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pubs.record-created-at-source-date |
2023-09-13 |
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pubs.online-publication-date |
2022-10-04 |
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