Rayleigh wave constraints on the structure and tectonic history of the Gamburtsev Subglacial Mountains, East Antarctica

TitleRayleigh wave constraints on the structure and tectonic history of the Gamburtsev Subglacial Mountains, East Antarctica
Publication TypeJournal Article
Year of Publication2013
AuthorsHeeszel D.S, Wiens D.A, Nyblade A.A, Hansen S.E, Kanao M., An M.J, Zhao Y.
JournalJournal of Geophysical Research-Solid Earth
Date Published2013/05
Type of ArticleArticle
ISBN Number2169-9313
Accession NumberWOS:000327299800019
Keywordsazimuthal anisotropy; basement provinces; Continental Dynamics; continental lithosphere; east antarctica; Gamburtsev; ice-sheet; Mantle Velocity; prince-charles mountains; Rayleigh Wave Tomogarphy; seismic structure; structure; structure beneath; Subglacial Mountains; trans-hudson-orogen; upper-mantle; velocity

The Gamburtsev Subglacial Mountains (GSM), located near the center of East Antarctica, remain one of the most enigmatic mountain ranges on Earth. A lack of direct geologic samples renders their tectonic history almost totally unconstrained. We utilize teleseismic Rayleigh wave data from a 2 year deployment of broadband seismic stations across the region to image shear velocity structure and analyze the lithospheric age of the GSM and surrounding regions. We solve for 2-D phase velocities and invert these results for 3-D shear velocity structure. We perform a Monte Carlo simulation to improve constraints of crustal thickness and shear velocity structure. Beneath the core of the GSM, we find crustal thickness in excess of 55km. Mantle shear velocities remain faster than global average models to a depth of approximately 250km, indicating a thick lithospheric root. Thinner crust and slower upper mantle velocities are observed beneath the Lambert Rift System and the Polar Subglacial Basin. When compared with phase velocity curves corresponding to specific tectonothermal ages elsewhere in the world, average phase velocity results for the GSM are consistent with regions of Archean-Paleoproterozoic origin. Combined with radiometric ages of detrital zircons found offshore, these results indicate a region of old crust that has undergone repeated periods of uplift and erosion, most recently during the Mesozoic breakup of Gondwana. Lower crustal seismic velocities imply a moderately dense lower crust beneath the core of the GSM, but with lower density than suggested by recent gravity models.

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