The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow
We present a shear wave model of the West Antarctic upper mantle to 200 km depth with enhanced regional resolution from the 2016-2018 UK Antarctic Seismic Network. The model is constructed from the combination of fundamental mode Rayleigh wave phase velocities extracted from ambient noise (periods 8...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:150032 2023-05-15T13:34:43+02:00 The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow O'Donnell, JP Stuart, GW Brisbourne, AM Selway, K Yang, Y Nield, GA Whitehouse, PL Nyblade, AA Wiens, DA Aster, RC Anandakrishnan, S Huerta, AD WIlson, T Winberry, JP 2019-09-15 text https://eprints.whiterose.ac.uk/150032/ https://eprints.whiterose.ac.uk/150032/1/O%27Donnell_et_al_accepted_EPSL.pdf en eng Elsevier https://eprints.whiterose.ac.uk/150032/1/O%27Donnell_et_al_accepted_EPSL.pdf O'Donnell, JP, Stuart, GW, Brisbourne, AM et al. (11 more authors) (2019) The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow. Earth and Planetary Science Letters, 522. pp. 219-233. ISSN 1385-013X cc_by_nc_nd_4 CC-BY-NC-ND Article NonPeerReviewed 2019 ftleedsuniv 2023-01-30T22:21:43Z We present a shear wave model of the West Antarctic upper mantle to 200 km depth with enhanced regional resolution from the 2016-2018 UK Antarctic Seismic Network. The model is constructed from the combination of fundamental mode Rayleigh wave phase velocities extracted from ambient noise (periods 8-25 s) and earthquake data by two-plane wave analysis (periods 20-143 s). We seek to (i) image and interpret structures against the tectonic evolution of West Antarctica, and (ii) extract information from the seismic model that can serve as boundary conditions in ice sheet and glacial isostatic adjustment modelling e orts. The distribution of low velocity anomalies in the uppermost mantle suggests that recent tectonism in the West Antarctic Rift System (WARS) is mainly concentrated beneath the rift margins and largely confined to the uppermost mantle (<180 km). On the northern margin of the WARS, a pronounced low velocity anomaly extends eastward from beneath the Marie Byrd Land dome toward Pine Island Bay, underlying Thwaites Glacier, but not Pine Island Glacier. If of plume-related thermal origin, the velocity contrast of 5% between this anomaly and the inner WARS translates to a temperature difference of 125-200°C. However, the strike of the anomaly parallels the paleo-Pacifc convergent margin of Gondwana, so it may reflect subduction-related melt and volatiles rather than anomalously elevated temperatures, or a combination thereof. Motivated by xenolith analyses, we speculate that high velocity zones imaged south of the Marie Byrd Land dome and in the eastern Ross Sea Embayment might reflect the compositional signature of ancient continental fragments. A pronounced low velocity anomaly underlying the southern Transantarctic Mountains (TAM) is consistent with a published lithospheric foundering hypothesis. Taken together with a magnetotelluric study advocating texural support of the central TAM by thick, stable lithosphere, this points to along-strike variation in the tectonic history of the TAM. A high velocity ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Marie Byrd Land Pine Island Pine Island Bay Pine Island Glacier Ross Sea Thwaites Glacier West Antarctica White Rose Research Online (Universities of Leeds, Sheffield & York) Antarctic Ross Sea West Antarctica Transantarctic Mountains Byrd Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) Island Bay ENVELOPE(-109.085,-109.085,59.534,59.534) Pine Island Bay ENVELOPE(-102.000,-102.000,-74.750,-74.750) Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
We present a shear wave model of the West Antarctic upper mantle to 200 km depth with enhanced regional resolution from the 2016-2018 UK Antarctic Seismic Network. The model is constructed from the combination of fundamental mode Rayleigh wave phase velocities extracted from ambient noise (periods 8-25 s) and earthquake data by two-plane wave analysis (periods 20-143 s). We seek to (i) image and interpret structures against the tectonic evolution of West Antarctica, and (ii) extract information from the seismic model that can serve as boundary conditions in ice sheet and glacial isostatic adjustment modelling e orts. The distribution of low velocity anomalies in the uppermost mantle suggests that recent tectonism in the West Antarctic Rift System (WARS) is mainly concentrated beneath the rift margins and largely confined to the uppermost mantle (<180 km). On the northern margin of the WARS, a pronounced low velocity anomaly extends eastward from beneath the Marie Byrd Land dome toward Pine Island Bay, underlying Thwaites Glacier, but not Pine Island Glacier. If of plume-related thermal origin, the velocity contrast of 5% between this anomaly and the inner WARS translates to a temperature difference of 125-200°C. However, the strike of the anomaly parallels the paleo-Pacifc convergent margin of Gondwana, so it may reflect subduction-related melt and volatiles rather than anomalously elevated temperatures, or a combination thereof. Motivated by xenolith analyses, we speculate that high velocity zones imaged south of the Marie Byrd Land dome and in the eastern Ross Sea Embayment might reflect the compositional signature of ancient continental fragments. A pronounced low velocity anomaly underlying the southern Transantarctic Mountains (TAM) is consistent with a published lithospheric foundering hypothesis. Taken together with a magnetotelluric study advocating texural support of the central TAM by thick, stable lithosphere, this points to along-strike variation in the tectonic history of the TAM. A high velocity ... |
format |
Article in Journal/Newspaper |
author |
O'Donnell, JP Stuart, GW Brisbourne, AM Selway, K Yang, Y Nield, GA Whitehouse, PL Nyblade, AA Wiens, DA Aster, RC Anandakrishnan, S Huerta, AD WIlson, T Winberry, JP |
spellingShingle |
O'Donnell, JP Stuart, GW Brisbourne, AM Selway, K Yang, Y Nield, GA Whitehouse, PL Nyblade, AA Wiens, DA Aster, RC Anandakrishnan, S Huerta, AD WIlson, T Winberry, JP The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
author_facet |
O'Donnell, JP Stuart, GW Brisbourne, AM Selway, K Yang, Y Nield, GA Whitehouse, PL Nyblade, AA Wiens, DA Aster, RC Anandakrishnan, S Huerta, AD WIlson, T Winberry, JP |
author_sort |
O'Donnell, JP |
title |
The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
title_short |
The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
title_full |
The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
title_fullStr |
The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
title_full_unstemmed |
The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
title_sort |
uppermost mantle seismic velocity structure of west antarctica from rayleigh wave tomography: insights into tectonic structure and geothermal heat flow |
publisher |
Elsevier |
publishDate |
2019 |
url |
https://eprints.whiterose.ac.uk/150032/ https://eprints.whiterose.ac.uk/150032/1/O%27Donnell_et_al_accepted_EPSL.pdf |
long_lat |
ENVELOPE(-101.000,-101.000,-75.000,-75.000) ENVELOPE(-130.000,-130.000,-78.000,-78.000) ENVELOPE(-109.085,-109.085,59.534,59.534) ENVELOPE(-102.000,-102.000,-74.750,-74.750) ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic Ross Sea West Antarctica Transantarctic Mountains Byrd Pine Island Glacier Marie Byrd Land Island Bay Pine Island Bay Thwaites Glacier |
geographic_facet |
Antarctic Ross Sea West Antarctica Transantarctic Mountains Byrd Pine Island Glacier Marie Byrd Land Island Bay Pine Island Bay Thwaites Glacier |
genre |
Antarc* Antarctic Antarctica Ice Sheet Marie Byrd Land Pine Island Pine Island Bay Pine Island Glacier Ross Sea Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Marie Byrd Land Pine Island Pine Island Bay Pine Island Glacier Ross Sea Thwaites Glacier West Antarctica |
op_relation |
https://eprints.whiterose.ac.uk/150032/1/O%27Donnell_et_al_accepted_EPSL.pdf O'Donnell, JP, Stuart, GW, Brisbourne, AM et al. (11 more authors) (2019) The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: insights into tectonic structure and geothermal heat flow. Earth and Planetary Science Letters, 522. pp. 219-233. ISSN 1385-013X |
op_rights |
cc_by_nc_nd_4 |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766056469063532544 |