Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis
Using data from the new Transantarctic Mountains Northern Network, this study aims to constrain azimuthal anisotropy beneath a previously unexplored portion of the Transantarctic Mountains (TAMs) to assess both past and present deformational processes occurring in this region. Shear‐wave splitting p...
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ftunivalabama:oai:ir.ua.edu:123456789/4065 2023-05-15T13:56:41+02:00 Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis Graw, Jordan H. Hansen, Samantha E. Antarctica 2017-02-12 http://ir.ua.edu/handle/123456789/4065 unknown http://ir.ua.edu/handle/123456789/4065 shear‐wave splitting Transantarctic Mountains anisotropy text 2017 ftunivalabama 2023-01-07T16:38:59Z Using data from the new Transantarctic Mountains Northern Network, this study aims to constrain azimuthal anisotropy beneath a previously unexplored portion of the Transantarctic Mountains (TAMs) to assess both past and present deformational processes occurring in this region. Shear‐wave splitting parameters have been measured for PKS, SKS, and SKKS phases using the eigenvalue method within the SplitLab software package. Results show two distinct geographic regions of anisotropy within our study area: one behind the TAMs front, with an average fast axis direction of 42 ± 3° and an average delay time of 0.9 ± 0.04 s, and the other within the TAMs near the Ross Sea coastline, with an average fast axis oriented at 51 ± 5° and an average delay time of 1.5 ± 0.08 s. Behind the TAMs front, our results are best explained by a single anisotropic layer that is estimated to be 81–135 km thick, thereby constraining the anisotropic signature within the East Antarctic lithosphere. We interpret the anisotropy behind the TAMs front as relict fabric associated with tectonic episodes occurring early in Antarctica's geologic history. For the coastal stations, our results are best explained by a single anisotropic layer estimated to be 135–225 km thick. This places the anisotropic source within the viscous asthenosphere, which correlates with low seismic velocities along the edge of the West Antarctic Rift System. We interpret the coastal anisotropic signature as resulting from active mantle flow associated with rift‐related decompression melting and Cenozoic extension. Text Antarc* Antarctic Antarctica Ross Sea University of Alabama Institutional Repository Antarctic Ross Sea Transantarctic Mountains |
institution |
Open Polar |
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University of Alabama Institutional Repository |
op_collection_id |
ftunivalabama |
language |
unknown |
topic |
shear‐wave splitting Transantarctic Mountains anisotropy |
spellingShingle |
shear‐wave splitting Transantarctic Mountains anisotropy Graw, Jordan H. Hansen, Samantha E. Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
topic_facet |
shear‐wave splitting Transantarctic Mountains anisotropy |
description |
Using data from the new Transantarctic Mountains Northern Network, this study aims to constrain azimuthal anisotropy beneath a previously unexplored portion of the Transantarctic Mountains (TAMs) to assess both past and present deformational processes occurring in this region. Shear‐wave splitting parameters have been measured for PKS, SKS, and SKKS phases using the eigenvalue method within the SplitLab software package. Results show two distinct geographic regions of anisotropy within our study area: one behind the TAMs front, with an average fast axis direction of 42 ± 3° and an average delay time of 0.9 ± 0.04 s, and the other within the TAMs near the Ross Sea coastline, with an average fast axis oriented at 51 ± 5° and an average delay time of 1.5 ± 0.08 s. Behind the TAMs front, our results are best explained by a single anisotropic layer that is estimated to be 81–135 km thick, thereby constraining the anisotropic signature within the East Antarctic lithosphere. We interpret the anisotropy behind the TAMs front as relict fabric associated with tectonic episodes occurring early in Antarctica's geologic history. For the coastal stations, our results are best explained by a single anisotropic layer estimated to be 135–225 km thick. This places the anisotropic source within the viscous asthenosphere, which correlates with low seismic velocities along the edge of the West Antarctic Rift System. We interpret the coastal anisotropic signature as resulting from active mantle flow associated with rift‐related decompression melting and Cenozoic extension. |
format |
Text |
author |
Graw, Jordan H. Hansen, Samantha E. |
author_facet |
Graw, Jordan H. Hansen, Samantha E. |
author_sort |
Graw, Jordan H. |
title |
Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
title_short |
Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
title_full |
Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
title_fullStr |
Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
title_full_unstemmed |
Upper Mantle Seismic Anisotropy beneath the Northern Transantarctic Mountains, Antarctica from PKS, SKS, and SKKS Splitting Analysis |
title_sort |
upper mantle seismic anisotropy beneath the northern transantarctic mountains, antarctica from pks, sks, and skks splitting analysis |
publishDate |
2017 |
url |
http://ir.ua.edu/handle/123456789/4065 |
op_coverage |
Antarctica |
geographic |
Antarctic Ross Sea Transantarctic Mountains |
geographic_facet |
Antarctic Ross Sea Transantarctic Mountains |
genre |
Antarc* Antarctic Antarctica Ross Sea |
genre_facet |
Antarc* Antarctic Antarctica Ross Sea |
op_relation |
http://ir.ua.edu/handle/123456789/4065 |
_version_ |
1766264260000743424 |