Seismic anisotropy beneath Central Australia: A record of ancient lithospheric deformation

dc.contributor.authorEakin, Caroline
dc.contributor.authorFlashman, Claire
dc.contributor.authorAgrawal, Shubham
dc.date.accessioned2022-11-18T05:35:58Z
dc.date.issued2021-12-05
dc.description.abstractFrom 2008 to 2011 a broadband seismic array (BILBY) spanned the Australian continent from North to South, crossing the suture zone between the North and South Australian cratons, and traversing the Central Australian orogenic belt. Past tectonic events, including orogenies during the Proterozoic and Paleozoic, have left a long-lasting impression on the crustal and Moho structure of this inter-cratonic region. However, the impact of past tectonic activity on the lithosphere has been less clear. Here we present the first shear-wave splitting results for the BILBY array using a combination of SKS and PKS teleseismic phases to investigate patterns of deformation and seismic anisotropy within the upper mantle beneath central Australia. Null *KS observations are found to be abundant compared to observations of splitting, as has been widely reported by previous studies, but this appears to be largely due to a coincidental alignment of the inferred anisotropic fast direction with the back-azimuthal range at which most available events occur (140°-160°). Across the central Australian belt the station averaged fast directions tend to orientate ENE-WSW parallel with topographic, gravity, and magnetic trends. Northwards however, the fast directions switch orientation, instead following the NW-SE elongated geometry of the Tennant Creek Inlier, thus delineating a sharp lateral change in the underlying seismic anisotropy. Overall, evidence suggests that the splitting pattern likely reflects anisotropy inherent within the lithosphere generated by past deformational events over 300 million plus years ago, as opposed to the present-day mantle flow in the asthenosphere. While two distinct layers of anisotropy, present in both the asthenosphere and lithosphere, is supported by other evidence, it is not necessarily required by our current dataset. Instead, we can sufficiently model our results with only a single layer of anisotropy, consistent with the expected geometry of azimuthal anisotropy in the lithosphere.en_AU
dc.description.sponsorshipThis work was supported by an Australian Research Council Dis- covery Early Career Researcher Award (DE190100062) and The Australian National University. Deployment of the BILBY array was supported by ARC Discovery Project (DP0662984)en_AU
dc.format.mimetypeapplication/pdfen_AU
dc.identifier.issn0040-1951en_AU
dc.identifier.urihttp://hdl.handle.net/1885/280337
dc.language.isoen_AUen_AU
dc.provenancehttps://v2.sherpa.ac.uk/id/publication/12912..."The Accepted Version can be archived in an Institutional Repository. 24 Months. CC BY-NC-ND." from SHERPA/RoMEO site (as at 18/11/2022).en_AU
dc.publisherElsevieren_AU
dc.relationhttp://purl.org/au-research/grants/arc/DE190100062en_AU
dc.relationhttp://purl.org/au-research/grants/arc/DP0662984en_AU
dc.rights© 2021 Elsevier B.V.en_AU
dc.rights.licenseCreative Commons Attribution-NonCommercial-NoDerivs Licenseen_AU
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/en_AU
dc.sourceTectonophysicsen_AU
dc.subjectSeismic anisotropyen_AU
dc.subjectAustraliaen_AU
dc.subjectShear-wave splittingen_AU
dc.subjectContinental deformationen_AU
dc.subjectSuture zoneen_AU
dc.subjectLithosphereen_AU
dc.titleSeismic anisotropy beneath Central Australia: A record of ancient lithospheric deformationen_AU
dc.typeJournal articleen_AU
dcterms.accessRightsOpen Accessen_AU
local.bibliographicCitation.startpage229123en_AU
local.contributor.affiliationEakin, C., Research School of Earth Sciences, The Australian National Universityen_AU
local.contributor.authoremailcaroline.eakin@anu.edu.auen_AU
local.contributor.authoruidu1017995en_AU
local.identifier.absfor370609 - Seismology and seismic explorationen_AU
local.identifier.absseo280107 - Expanding knowledge in the earth sciencesen_AU
local.identifier.citationvolume820en_AU
local.identifier.doi10.1016/j.tecto.2021.229123en_AU
local.identifier.uidSubmittedByu1017995en_AU
local.publisher.urlhttps://www.elsevier.com/en-auen_AU
local.type.statusAccepted Versionen_AU

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