Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography

Electronic Thesis or Dissertation Stretching ~3,500 km across Antarctica, with peak elevations up to 4,500 m, the Transantarctic Mountains (TAMs) are the largest non-compressional continental mountain range on Earth and represent a tectonic boundary between the East Antarctica (EA) craton and the We...

Full description

Bibliographic Details
Main Author: Brenn, Gregory
Other Authors: Hansen, Samantha E., Robinson, D. M., Zhang, Bo, Nyblade, Andrew A.
Format: Thesis
Language:English
Published: University of Alabama Libraries 2016
Subjects:
Online Access:https://ir.ua.edu/handle/123456789/2769
id ftunivalabama:oai:ir.ua.edu:123456789/2769
record_format openpolar
spelling ftunivalabama:oai:ir.ua.edu:123456789/2769 2023-05-15T13:56:41+02:00 Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography Brenn, Gregory Hansen, Samantha E. Robinson, D. M. Zhang, Bo Nyblade, Andrew A. 2016 94 p. https://ir.ua.edu/handle/123456789/2769 English eng University of Alabama Libraries The University of Alabama Electronic Theses and Dissertations The University of Alabama Libraries Digital Collections https://ir.ua.edu/handle/123456789/2769 All rights reserved by the author unless otherwise indicated. Geophysics thesis text 2016 ftunivalabama 2023-01-07T16:38:37Z Electronic Thesis or Dissertation Stretching ~3,500 km across Antarctica, with peak elevations up to 4,500 m, the Transantarctic Mountains (TAMs) are the largest non-compressional continental mountain range on Earth and represent a tectonic boundary between the East Antarctica (EA) craton and the West Antarctic Rift System. The origin and uplift mechanism associated with the TAMs is controversial, and multiple models have been proposed. Seismic investigations of the TAM’s subsurface structure can provide key constraints to help evaluate these models, but previous studies have been primarily focused only on the central TAMs near Ross Island. Using data from the new 15-station Transantarctic Mountain Northern Network as well as data from several smaller networks, this study investigates the upper mantle velocity structure beneath a previously unexplored portion of the northern TAMs through regional body wave tomography. Relative travel-times were calculated for 11,182 P-wave and 8,285 S-wave arrivals from 790 and 581 Mw ≥ 5.5 events, respectively, using multi-channel cross correlation, and these data were then inverted for models of the upper mantle seismic structure. Resulting P- and S-wave tomography images reveal two focused low velocity anomalies beneath Ross Island (RI; δVP ≈ -2.0%; δVS ≈ -1.5% to -4.0%) and Terra Nova Bay (TNB; δVP ≈ -1.5% to -2.0%; δVS ≈ -1.0% to -4.0%) that extend to depths of ~200 and ~150 km, respectively. The RI and TNB slow anomalies also extend ~50-100 km laterally beneath the TAMs front and sharply abut fast velocities beneath the EA craton (δVP ≈ 0.5% to 2%; δVS ≈ 1.5% to 4.0%). A low velocity region (δVP ≈ -1.5%), centered at ~150 km depth beneath the Terror Rift (TR) and primarily constrained within the Victoria Land Basin, connects the RI and TNB anomalies. The focused low velocities are interpreted as regions of partial melt and buoyancy-driven upwelling, connected by a broad region of slow (presumably warm) upper mantle associated with Cenozoic extension along the TR. Dynamic ... Thesis Antarc* Antarctic Antarctica East Antarctica Ross Island Victoria Land University of Alabama Institutional Repository Antarctic East Antarctica Ross Island Terra Nova Bay Transantarctic Mountains Victoria Land
institution Open Polar
collection University of Alabama Institutional Repository
op_collection_id ftunivalabama
language English
topic Geophysics
spellingShingle Geophysics
Brenn, Gregory
Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
topic_facet Geophysics
description Electronic Thesis or Dissertation Stretching ~3,500 km across Antarctica, with peak elevations up to 4,500 m, the Transantarctic Mountains (TAMs) are the largest non-compressional continental mountain range on Earth and represent a tectonic boundary between the East Antarctica (EA) craton and the West Antarctic Rift System. The origin and uplift mechanism associated with the TAMs is controversial, and multiple models have been proposed. Seismic investigations of the TAM’s subsurface structure can provide key constraints to help evaluate these models, but previous studies have been primarily focused only on the central TAMs near Ross Island. Using data from the new 15-station Transantarctic Mountain Northern Network as well as data from several smaller networks, this study investigates the upper mantle velocity structure beneath a previously unexplored portion of the northern TAMs through regional body wave tomography. Relative travel-times were calculated for 11,182 P-wave and 8,285 S-wave arrivals from 790 and 581 Mw ≥ 5.5 events, respectively, using multi-channel cross correlation, and these data were then inverted for models of the upper mantle seismic structure. Resulting P- and S-wave tomography images reveal two focused low velocity anomalies beneath Ross Island (RI; δVP ≈ -2.0%; δVS ≈ -1.5% to -4.0%) and Terra Nova Bay (TNB; δVP ≈ -1.5% to -2.0%; δVS ≈ -1.0% to -4.0%) that extend to depths of ~200 and ~150 km, respectively. The RI and TNB slow anomalies also extend ~50-100 km laterally beneath the TAMs front and sharply abut fast velocities beneath the EA craton (δVP ≈ 0.5% to 2%; δVS ≈ 1.5% to 4.0%). A low velocity region (δVP ≈ -1.5%), centered at ~150 km depth beneath the Terror Rift (TR) and primarily constrained within the Victoria Land Basin, connects the RI and TNB anomalies. The focused low velocities are interpreted as regions of partial melt and buoyancy-driven upwelling, connected by a broad region of slow (presumably warm) upper mantle associated with Cenozoic extension along the TR. Dynamic ...
author2 Hansen, Samantha E.
Robinson, D. M.
Zhang, Bo
Nyblade, Andrew A.
format Thesis
author Brenn, Gregory
author_facet Brenn, Gregory
author_sort Brenn, Gregory
title Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
title_short Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
title_full Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
title_fullStr Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
title_full_unstemmed Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
title_sort determining the upper mantle seismic structure beneath the northern transantarctic mountains, antarctica, form regional p- and s-wave tomography
publisher University of Alabama Libraries
publishDate 2016
url https://ir.ua.edu/handle/123456789/2769
geographic Antarctic
East Antarctica
Ross Island
Terra Nova Bay
Transantarctic Mountains
Victoria Land
geographic_facet Antarctic
East Antarctica
Ross Island
Terra Nova Bay
Transantarctic Mountains
Victoria Land
genre Antarc*
Antarctic
Antarctica
East Antarctica
Ross Island
Victoria Land
genre_facet Antarc*
Antarctic
Antarctica
East Antarctica
Ross Island
Victoria Land
op_relation The University of Alabama Electronic Theses and Dissertations
The University of Alabama Libraries Digital Collections
https://ir.ua.edu/handle/123456789/2769
op_rights All rights reserved by the author unless otherwise indicated.
_version_ 1766264258958458880