Timescales for pluton growth, magma-chamber formation and super-eruptions
Generation of silicic magmas leads to emplacement of granite plutons, huge explosive volcanic eruptions and physical and chemical zoning of continental and arc crust1-7. Whereas timescales for silicic magma generation in the deep and middle crust are prolonged8, magma transfer into the upper crust f...
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Published in | Nature (London) Vol. 608; no. 7921; pp. 87 - 92 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group
04.08.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Generation of silicic magmas leads to emplacement of granite plutons, huge explosive volcanic eruptions and physical and chemical zoning of continental and arc crust1-7. Whereas timescales for silicic magma generation in the deep and middle crust are prolonged8, magma transfer into the upper crust followed by eruption is episodic and can be rapid9-12. Ages of inherited zircons and sanidines from four Miocene ignimbrites in the Central Andes indicate a gap of 4.6 Myr between initiation of pluton emplacement and onset of super-eruptions, with a 1-Myr cyclicity. We show that inherited zircons and sanidine crystals were stored at temperatures <470 °C in these plutons before incorporation in ignimbrite magmas. Our observations can be explained by silicic melt segregation in a middle-crustal hot zone with episodic melt ascent from an unstable layer at the top of the zone with a timescale governed by the rheology of the upper crust. After thermal incubation of growing plutons, large upper-crustal magma chambers can form in a few thousand years or less by dike transport from the hot-zone melt layer. Instability and disruption of earlier plutonic rock occurred in a few decades or less just before or during super-eruptions. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0028-0836 1476-4687 |
DOI: | 10.1038/s41586-022-04921-9 |