Timescales for pluton growth, magma-chamber formation and super-eruptions

van Zalinge, M.E., Mark, D.E. , Sparks, R.S.J., Tremblay, M.M., Keller, C.B., Cooper, F.J. and Rust, A. (2022) Timescales for pluton growth, magma-chamber formation and super-eruptions. Nature, 608(7921), pp. 87-92. (doi: 10.1038/s41586-022-04921-9) (PMID:35922502)

Abstract

Generation of silicic magmas leads to emplacement of granite plutons, huge explosive volcanic eruptions and physical and chemical zoning of continental and arc crust1,2,3,4,5,6,7. 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 rapid9,10,11,12. 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.

• Item Type: Articles
• Additional Information: Zircon and sanidine analyses were supported by Natural Environment Research Council (NERC) Isotope Geosciences Facilities Steering Committee grant IP-1466-1114 and Royal Society Research Grant RG140683 to F.J.C. D. Condon is thanked for his help with the analyses of inherited zircons. NERC are thanked for continued funding of the National Environmental Isotope Facility. R.S.J.S. acknowledges support of a Leverhulme Trust Emeritus Fellowship.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Mark, Professor Darren
• Authors: van Zalinge, M.E., Mark, D.E., Sparks, R.S.J., Tremblay, M.M., Keller, C.B., Cooper, F.J., and Rust, A.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Nature
• Publisher: Nature Research
• ISSN: 0028-0836
• ISSN (Online): 1476-4687
• Published Online: 03 August 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Nature 608(7921): 87-92
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

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• Data DOI: 10.26022/IEDA/112268