Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism
Alaska has been a site of subduction and terrane accretion since the mid‐Jurassic. The area features abundant seismicity, active volcanism, rapid uplift, and broad intraplate deformation, all associated with subduction of the Pacific plate beneath North America. The juxtaposition of a slab edge with...
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/253469 2024-01-14T10:11:20+01:00 Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism Martin-Short, Robert Allen, Richard M. Bastow, Ian D Porritt, Robert Miller, Meghan application/pdf http://hdl.handle.net/1885/253469 https://doi.org/10.1029/2018GC007962 https://openresearch-repository.anu.edu.au/bitstream/1885/253469/3/01_Martin-Short_Seismic_imaging_of_the_Alaska_2018.pdf.jpg en_AU eng American Geophysical Union 1525-2027 http://hdl.handle.net/1885/253469 doi:10.1029/2018GC007962 https://openresearch-repository.anu.edu.au/bitstream/1885/253469/3/01_Martin-Short_Seismic_imaging_of_the_Alaska_2018.pdf.jpg © 2018. American Geophysical Union Geochemistry, Geophysics, Geosystems Journal article ftanucanberra https://doi.org/10.1029/2018GC007962 2023-12-15T09:37:18Z Alaska has been a site of subduction and terrane accretion since the mid‐Jurassic. The area features abundant seismicity, active volcanism, rapid uplift, and broad intraplate deformation, all associated with subduction of the Pacific plate beneath North America. The juxtaposition of a slab edge with subducted, overthickened crust of the Yakutat terrane beneath central Alaska is associated with many enigmatic volcanic features. The causes of the Denali Volcanic Gap, a 400‐km‐long zone of volcanic quiescence west of the slab edge, are debated. Furthermore, the Wrangell Volcanic Field, southeast of the volcanic gap, also has an unexplained relationship with subduction. To address these issues, we present a joint ambient noise, earthquake‐based surface wave, and P‐S receiver function tomography model of Alaska, along with a teleseismic S wave velocity model. We compare the crust and mantle structure between the volcanic and nonvolcanic regions, across the eastern edge of the slab and between models. Low crustal velocities correspond to sedimentary basins, and several terrane boundaries are marked by changes in Moho depth. The continental lithosphere directly beneath the Denali Volcanic Gap is thicker than in the adjacent volcanic region. We suggest that shallow subduction here has cooled the mantle wedge, allowing the formation of thick lithosphere by the prevention of hot asthenosphere from reaching depths where it can interact with fluids released from the slab and promote volcanism. There is no evidence for subducted material east of the edge of the Yakutat terrane, implying the Wrangell Volcanic Field formed directly above a slab edge. Article in Journal/Newspaper Yakutat Alaska Australian National University: ANU Digital Collections Pacific Geochemistry, Geophysics, Geosystems 19 11 4541 4560 |
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Open Polar |
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Australian National University: ANU Digital Collections |
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ftanucanberra |
language |
English |
description |
Alaska has been a site of subduction and terrane accretion since the mid‐Jurassic. The area features abundant seismicity, active volcanism, rapid uplift, and broad intraplate deformation, all associated with subduction of the Pacific plate beneath North America. The juxtaposition of a slab edge with subducted, overthickened crust of the Yakutat terrane beneath central Alaska is associated with many enigmatic volcanic features. The causes of the Denali Volcanic Gap, a 400‐km‐long zone of volcanic quiescence west of the slab edge, are debated. Furthermore, the Wrangell Volcanic Field, southeast of the volcanic gap, also has an unexplained relationship with subduction. To address these issues, we present a joint ambient noise, earthquake‐based surface wave, and P‐S receiver function tomography model of Alaska, along with a teleseismic S wave velocity model. We compare the crust and mantle structure between the volcanic and nonvolcanic regions, across the eastern edge of the slab and between models. Low crustal velocities correspond to sedimentary basins, and several terrane boundaries are marked by changes in Moho depth. The continental lithosphere directly beneath the Denali Volcanic Gap is thicker than in the adjacent volcanic region. We suggest that shallow subduction here has cooled the mantle wedge, allowing the formation of thick lithosphere by the prevention of hot asthenosphere from reaching depths where it can interact with fluids released from the slab and promote volcanism. There is no evidence for subducted material east of the edge of the Yakutat terrane, implying the Wrangell Volcanic Field formed directly above a slab edge. |
format |
Article in Journal/Newspaper |
author |
Martin-Short, Robert Allen, Richard M. Bastow, Ian D Porritt, Robert Miller, Meghan |
spellingShingle |
Martin-Short, Robert Allen, Richard M. Bastow, Ian D Porritt, Robert Miller, Meghan Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
author_facet |
Martin-Short, Robert Allen, Richard M. Bastow, Ian D Porritt, Robert Miller, Meghan |
author_sort |
Martin-Short, Robert |
title |
Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
title_short |
Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
title_full |
Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
title_fullStr |
Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
title_full_unstemmed |
Seismic imaging of the Alaska subduction zone: implications for slab geometry and volcanism |
title_sort |
seismic imaging of the alaska subduction zone: implications for slab geometry and volcanism |
publisher |
American Geophysical Union |
url |
http://hdl.handle.net/1885/253469 https://doi.org/10.1029/2018GC007962 https://openresearch-repository.anu.edu.au/bitstream/1885/253469/3/01_Martin-Short_Seismic_imaging_of_the_Alaska_2018.pdf.jpg |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Yakutat Alaska |
genre_facet |
Yakutat Alaska |
op_source |
Geochemistry, Geophysics, Geosystems |
op_relation |
1525-2027 http://hdl.handle.net/1885/253469 doi:10.1029/2018GC007962 https://openresearch-repository.anu.edu.au/bitstream/1885/253469/3/01_Martin-Short_Seismic_imaging_of_the_Alaska_2018.pdf.jpg |
op_rights |
© 2018. American Geophysical Union |
op_doi |
https://doi.org/10.1029/2018GC007962 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
19 |
container_issue |
11 |
container_start_page |
4541 |
op_container_end_page |
4560 |
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1788066248405286912 |