Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography
We determine high-resolution tomographic models of isotropic P-wave velocity (Vp) and tilting-axis anisotropy of the Alaska subduction zone using a large number of local and teleseismic data recorded at many portable and permanent network stations in and around Alaska. We find a flat high-Vp slab in...
Published in: | Journal of Geophysical Research: Solid Earth |
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Online Access: | http://ir.gig.ac.cn/handle/344008/76015 http://ir.gig.ac.cn/handle/344008/76016 https://doi.org/10.1029/2023JB027617 |
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ftchacadscgigcas:oai:ir.gig.ac.cn:344008/76016 2024-09-30T14:33:07+00:00 Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography Liang, Xuran Zhao, Dapeng Hua, Yuanyuan Xu, Yi-Gang 2024 http://ir.gig.ac.cn/handle/344008/76015 http://ir.gig.ac.cn/handle/344008/76016 https://doi.org/10.1029/2023JB027617 英语 eng JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH http://ir.gig.ac.cn/handle/344008/76015 http://ir.gig.ac.cn/handle/344008/76016 doi:10.1029/2023JB027617 Geochemistry & Geophysics 期刊论文 2024 ftchacadscgigcas https://doi.org/10.1029/2023JB027617 2024-09-16T14:26:10Z We determine high-resolution tomographic models of isotropic P-wave velocity (Vp) and tilting-axis anisotropy of the Alaska subduction zone using a large number of local and teleseismic data recorded at many portable and permanent network stations in and around Alaska. We find a flat high-Vp slab in the mantle transition zone (410-670 km depths) beneath western Alaska, which is connected with the subducting Pacific slab at 0-410 km depths, suggesting that a big mantle wedge has formed under western Alaska. Our tilting-axis anisotropy model reveals complex mantle flows in the asthenosphere. Corner flow in the mantle wedge above the subducting Pacific slab and toroidal flow in the big mantle wedge are revealed, which may cause the Cenozoic intraplate volcanoes in western Alaska and the Bering Sea. In central Alaska, the mantle wedge beneath the Denali volcanic gap is characterized by high-Vp and subhorizontal fast velocity directions normal to the volcanic arc, which may reflect a remnant of the subducted Yakutat slab. In SE Alaska, the shallow subduction of the Wrangell slab is visible above 150 km depth, and hot mantle upwelling through the Wrangell-Yakutat slab gap may contribute to the Wrangell volcanic field. Alaska is home to over 100 Cenozoic volcanoes, but their formation mechanism is still puzzling. Here we use a large number of seismic data and a novel tomographic technique to obtain high-resolution images of isotropic P-wave velocity (Vp) and anisotropy down to 800 km depth beneath Alaska. Our results show that a flat high-Vp slab exists in the mantle transition zone (410-670 km depths) beneath western Alaska, where a big mantle wedge has formed above the flat slab. Fluids in the big mantle wedge and large-scale mantle flow around it have caused Cenozoic intraplate volcanoes near the Bering Sea. The Denali volcanic gap, different from its neighboring Buzzard Creek-Jumbo Dome volcanoes, has a high Vp mantle wedge with arc-normal fast anisotropy, which may reflect a cool fluid barrier from the Yakutat ... Report Bering Sea Yakutat Alaska Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) Bering Sea Pacific Tilting ENVELOPE(-54.065,-54.065,49.700,49.700) Journal of Geophysical Research: Solid Earth 129 1 |
institution |
Open Polar |
collection |
Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchacadscgigcas |
language |
English |
topic |
Geochemistry & Geophysics |
spellingShingle |
Geochemistry & Geophysics Liang, Xuran Zhao, Dapeng Hua, Yuanyuan Xu, Yi-Gang Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
topic_facet |
Geochemistry & Geophysics |
description |
We determine high-resolution tomographic models of isotropic P-wave velocity (Vp) and tilting-axis anisotropy of the Alaska subduction zone using a large number of local and teleseismic data recorded at many portable and permanent network stations in and around Alaska. We find a flat high-Vp slab in the mantle transition zone (410-670 km depths) beneath western Alaska, which is connected with the subducting Pacific slab at 0-410 km depths, suggesting that a big mantle wedge has formed under western Alaska. Our tilting-axis anisotropy model reveals complex mantle flows in the asthenosphere. Corner flow in the mantle wedge above the subducting Pacific slab and toroidal flow in the big mantle wedge are revealed, which may cause the Cenozoic intraplate volcanoes in western Alaska and the Bering Sea. In central Alaska, the mantle wedge beneath the Denali volcanic gap is characterized by high-Vp and subhorizontal fast velocity directions normal to the volcanic arc, which may reflect a remnant of the subducted Yakutat slab. In SE Alaska, the shallow subduction of the Wrangell slab is visible above 150 km depth, and hot mantle upwelling through the Wrangell-Yakutat slab gap may contribute to the Wrangell volcanic field. Alaska is home to over 100 Cenozoic volcanoes, but their formation mechanism is still puzzling. Here we use a large number of seismic data and a novel tomographic technique to obtain high-resolution images of isotropic P-wave velocity (Vp) and anisotropy down to 800 km depth beneath Alaska. Our results show that a flat high-Vp slab exists in the mantle transition zone (410-670 km depths) beneath western Alaska, where a big mantle wedge has formed above the flat slab. Fluids in the big mantle wedge and large-scale mantle flow around it have caused Cenozoic intraplate volcanoes near the Bering Sea. The Denali volcanic gap, different from its neighboring Buzzard Creek-Jumbo Dome volcanoes, has a high Vp mantle wedge with arc-normal fast anisotropy, which may reflect a cool fluid barrier from the Yakutat ... |
format |
Report |
author |
Liang, Xuran Zhao, Dapeng Hua, Yuanyuan Xu, Yi-Gang |
author_facet |
Liang, Xuran Zhao, Dapeng Hua, Yuanyuan Xu, Yi-Gang |
author_sort |
Liang, Xuran |
title |
Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
title_short |
Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
title_full |
Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
title_fullStr |
Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
title_full_unstemmed |
Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography |
title_sort |
big mantle wedge and intraplate volcanism in alaska: insight from anisotropic tomography |
publishDate |
2024 |
url |
http://ir.gig.ac.cn/handle/344008/76015 http://ir.gig.ac.cn/handle/344008/76016 https://doi.org/10.1029/2023JB027617 |
long_lat |
ENVELOPE(-54.065,-54.065,49.700,49.700) |
geographic |
Bering Sea Pacific Tilting |
geographic_facet |
Bering Sea Pacific Tilting |
genre |
Bering Sea Yakutat Alaska |
genre_facet |
Bering Sea Yakutat Alaska |
op_relation |
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH http://ir.gig.ac.cn/handle/344008/76015 http://ir.gig.ac.cn/handle/344008/76016 doi:10.1029/2023JB027617 |
op_doi |
https://doi.org/10.1029/2023JB027617 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
129 |
container_issue |
1 |
_version_ |
1811637131025580032 |