The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings
Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is se...
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ftcwashingtonuni:oai:digitalcommons.cwu.edu:geological_sciences-1017 2023-05-15T13:59:35+02:00 The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings Emry, E. L. Nyblade, Andrew A. Julia, J. Anandakrishnan, Sridhar Aster, R. C. Wiens, Douglas A. Huerta, Audrey D. Wilson, Terry J. 2015-01-08T08:00:00Z application/pdf https://digitalcommons.cwu.edu/geological_sciences/13 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1017&context=geological_sciences unknown ScholarWorks@CWU https://digitalcommons.cwu.edu/geological_sciences/13 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1017&context=geological_sciences Copyright © 2015 American Geophysical Union Geological Sciences Faculty Scholarship Antarctica mantle plume Geophysics and Seismology text 2015 ftcwashingtonuni 2022-10-20T20:24:58Z Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high-quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single-station and common conversion point stacks, migrated to depth using the AK135 velocity model, indicate that mantle transition zone thickness throughout most of West Antarctica does not differ significantly from the global average, except in two locations; one small region exhibits a vertically thinned (210 ± 15 km) transition zone beneath the Ruppert Coast of Marie Byrd Land and another laterally broader region shows slight, vertical thinning (225 ± 25 km) beneath the Bentley Subglacial Trench. We also observe the 520 discontinuity and a prominent negative peak above the mantle transition zone throughout much of West Antarctica. These results suggest that the mantle transition zone may be hotter than average in two places, possibly due to upwelling from the lower mantle, but not broadly across West Antarctica. Furthermore, we propose that the transition zone may be hydrated due to >100 million years of subduction beneath the region during the early Mesozoic. Text Antarc* Antarctic Antarctica Marie Byrd Land Ruppert coast West Antarctica Central Washington University: ScholarWorks Antarctic Bentley Subglacial Trench ENVELOPE(-105.000,-105.000,-80.000,-80.000) Byrd Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) Ruppert Coast ENVELOPE(-144.000,-144.000,-76.000,-76.000) The Antarctic West Antarctica |
institution |
Open Polar |
collection |
Central Washington University: ScholarWorks |
op_collection_id |
ftcwashingtonuni |
language |
unknown |
topic |
Antarctica mantle plume Geophysics and Seismology |
spellingShingle |
Antarctica mantle plume Geophysics and Seismology Emry, E. L. Nyblade, Andrew A. Julia, J. Anandakrishnan, Sridhar Aster, R. C. Wiens, Douglas A. Huerta, Audrey D. Wilson, Terry J. The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
topic_facet |
Antarctica mantle plume Geophysics and Seismology |
description |
Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high-quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single-station and common conversion point stacks, migrated to depth using the AK135 velocity model, indicate that mantle transition zone thickness throughout most of West Antarctica does not differ significantly from the global average, except in two locations; one small region exhibits a vertically thinned (210 ± 15 km) transition zone beneath the Ruppert Coast of Marie Byrd Land and another laterally broader region shows slight, vertical thinning (225 ± 25 km) beneath the Bentley Subglacial Trench. We also observe the 520 discontinuity and a prominent negative peak above the mantle transition zone throughout much of West Antarctica. These results suggest that the mantle transition zone may be hotter than average in two places, possibly due to upwelling from the lower mantle, but not broadly across West Antarctica. Furthermore, we propose that the transition zone may be hydrated due to >100 million years of subduction beneath the region during the early Mesozoic. |
format |
Text |
author |
Emry, E. L. Nyblade, Andrew A. Julia, J. Anandakrishnan, Sridhar Aster, R. C. Wiens, Douglas A. Huerta, Audrey D. Wilson, Terry J. |
author_facet |
Emry, E. L. Nyblade, Andrew A. Julia, J. Anandakrishnan, Sridhar Aster, R. C. Wiens, Douglas A. Huerta, Audrey D. Wilson, Terry J. |
author_sort |
Emry, E. L. |
title |
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
title_short |
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
title_full |
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
title_fullStr |
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
title_full_unstemmed |
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence for Hydration and Thermal Upwellings |
title_sort |
mantle transition zone beneath west antarctica: seismic evidence for hydration and thermal upwellings |
publisher |
ScholarWorks@CWU |
publishDate |
2015 |
url |
https://digitalcommons.cwu.edu/geological_sciences/13 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1017&context=geological_sciences |
long_lat |
ENVELOPE(-105.000,-105.000,-80.000,-80.000) ENVELOPE(-130.000,-130.000,-78.000,-78.000) ENVELOPE(-144.000,-144.000,-76.000,-76.000) |
geographic |
Antarctic Bentley Subglacial Trench Byrd Marie Byrd Land Ruppert Coast The Antarctic West Antarctica |
geographic_facet |
Antarctic Bentley Subglacial Trench Byrd Marie Byrd Land Ruppert Coast The Antarctic West Antarctica |
genre |
Antarc* Antarctic Antarctica Marie Byrd Land Ruppert coast West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Marie Byrd Land Ruppert coast West Antarctica |
op_source |
Geological Sciences Faculty Scholarship |
op_relation |
https://digitalcommons.cwu.edu/geological_sciences/13 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1017&context=geological_sciences |
op_rights |
Copyright © 2015 American Geophysical Union |
_version_ |
1766268187672838144 |