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Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, result...

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Autores principales: Hansen, S. M., Schmandt, B., Levander, A., Kiser, E., Vidale, J. E., Abers, G. A., Creager, K. C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5097125/
https://www.ncbi.nlm.nih.gov/pubmed/27802263
http://dx.doi.org/10.1038/ncomms13242
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author Hansen, S. M.
Schmandt, B.
Levander, A.
Kiser, E.
Vidale, J. E.
Abers, G. A.
Creager, K. C.
author_facet Hansen, S. M.
Schmandt, B.
Levander, A.
Kiser, E.
Vidale, J. E.
Abers, G. A.
Creager, K. C.
author_sort Hansen, S. M.
collection PubMed
description Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams.
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spelling pubmed-50971252016-11-18 Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens Hansen, S. M. Schmandt, B. Levander, A. Kiser, E. Vidale, J. E. Abers, G. A. Creager, K. C. Nat Commun Article Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams. Nature Publishing Group 2016-11-01 /pmc/articles/PMC5097125/ /pubmed/27802263 http://dx.doi.org/10.1038/ncomms13242 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Hansen, S. M.
Schmandt, B.
Levander, A.
Kiser, E.
Vidale, J. E.
Abers, G. A.
Creager, K. C.
Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title_full Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title_fullStr Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title_full_unstemmed Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title_short Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens
title_sort seismic evidence for a cold serpentinized mantle wedge beneath mount st helens
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5097125/
https://www.ncbi.nlm.nih.gov/pubmed/27802263
http://dx.doi.org/10.1038/ncomms13242
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