The crust and upper mantle structure of central and west Antarctica from bayesian inversion of rayleigh wave and receiver functions

TitleThe crust and upper mantle structure of central and west Antarctica from bayesian inversion of rayleigh wave and receiver functions
Publication TypeJournal Article
Year of Publication2018
AuthorsShen W.S, Wiens D.A, Anandakrishnan S., Aster R.C, Gerstoft P, Bromirski PD, Hansen S.E, Dalziel I.WD, Heeszel D.S, Huerta A.D, Nyblade A.A, Stephen R., Wilson T.J, Winberry J.P
JournalJournal of Geophysical Research-Solid Earth
Volume123
Pagination7824-7849
Date Published2018/09
Type of ArticleArticle
ISBN Number2169-9313
Accession NumberWOS:000447858800036
Keywordsaerogeophysical; Ambient noise tomography; antarctica; beneath; crust and uppermost mantle; data; east antarctica; Gamburtsev Mountains; Geochemistry & Geophysics; joint inversion; marie-byrd-land; northern transantarctic mountains; rift system; ross ice; seismic anisotropy; Seismology; Shelf; skks splitting analysis; Transantarctic Mountains; velocity structure beneath
Abstract

We construct a new seismic model for central and West Antarctica by jointly inverting Rayleigh wave phase and group velocities along with P wave receiver functions. Ambient noise tomography exploiting data from more than 200 seismic stations deployed over the past 18years is used to construct Rayleigh wave phase and group velocity dispersion maps. Comparison between the ambient noise phase velocity maps with those constructed using teleseismic earthquakes confirms the accuracy of both results. These maps, together with P receiver function waveforms, are used to construct a new 3-D shear velocity (Vs) model for the crust and uppermost mantle using a Bayesian Monte Carlo algorithm. The new 3-D seismic model shows the dichotomy of the tectonically active West Antarctica (WANT) and the stable and ancient East Antarctica (EANT). In WANT, the model exhibits a slow uppermost mantle along the Transantarctic Mountains (TAMs) front, interpreted as the thermal effect from Cenozoic rifting. Beneath the southern TAMs, the slow uppermost mantle extends horizontally beneath the traditionally recognized EANT, hypothesized to be associated with lithospheric delamination. Thin crust and lithosphere observed along the Amundsen Sea coast and extending into the interior suggest involvement of these areas in Cenozoic rifting. EANT, with its relatively thick and cold crust and lithosphere marked by high Vs, displays a slower Vs anomaly beneath the Gamburtsev Subglacial Mountains in the uppermost mantle, which we hypothesize may be the signature of a compositionally anomalous body, perhaps remnant from a continental collision.

DOI10.1029/2017jb015346
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