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

dc.contributorRobinson, D. M.
dc.contributorZhang, Bo
dc.contributorNyblade, Andrew A.
dc.contributor.advisorHansen, Samantha E.
dc.contributor.authorBrenn, Gregory
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2017-03-02T19:54:59Z
dc.date.available2017-03-02T19:54:59Z
dc.date.issued2016
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractStretching ~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 topography estimates based on the imaged S-wave velocity perturbations are consistent with observed surface topography in the central and northern TAMs, thereby providing support for uplift models that advocate for thermal loading and a flexural origin for the mountain range.en_US
dc.format.extent94 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0002484
dc.identifier.otherBrenn_alatus_0004M_12913
dc.identifier.urihttps://ir.ua.edu/handle/123456789/2769
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectGeophysics
dc.titleDetermining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomographyen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Geological Sciences
etdms.degree.disciplineGeology
etdms.degree.grantorThe University of Alabama
etdms.degree.levelmaster's
etdms.degree.nameM.S.
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