Recent extension driven by mantle upwelling at craton edge beneath the Admiralty Mountains (Ross Sea, East Antarctica)

Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System, WARS) and the thick, possibly cold East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and...

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Bibliographic Details
Main Authors: Faccenna, C., Rossetti, F., Becker, T. W., Danesi, S., Morelli, A.
Other Authors: Faccenna, C.; Dipartimento Scienze Geologiche, Università Roma TRE, Roma IT, Rossetti, F.; Dipartimento Scienze Geologiche, Università Roma TRE, Roma IT, Becker, T. W.; University of Southern California, Los Angeles CA (US), Danesi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia, Morelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia, Dipartimento Scienze Geologiche, Università Roma TRE, Roma IT, University of Southern California, Los Angeles CA (US), Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia
Format: Manuscript
Language:English
Published: 2007
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Online Access:http://hdl.handle.net/2122/2816
Description
Summary:Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System, WARS) and the thick, possibly cold East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and contrasting models have been proposed. We performed structural and morphotectonic analyses at the NE termination of northern Victoria Land in the Admiralty Mountains area, where the relationship between topography, tectonics and magmatism is expected to be well pronounced. We found evidence of two subsequent episodes of faulting, occurring concurrently with the Neogene Mc Murdo volcanism. The first episode is associated with dextral transtension and it is overprinted by extensional tectonics during the emplacement of large shield alkaline volcanoes. Upper mantle seismic tomography shows that the extensional regime is limited to regions overlying a low velocity anomaly. We interpret this anomaly to be of thermal origin, and have tested the role of large-scale upwelling on lithosphere deformation in the area. The results of this integrated analysis suggest that the morphotectonic setting of the region and the magmatism are likely the result of upwelling flow at the boundary between the cold cratonic and the hot stretched province (WARS), at work until recent time in this portion of the northern Victoria Land. Programma Nazionale di Ricerca in Antartide (PNRA) Submitted 3.3. Geodinamica e struttura dell'interno della Terra JCR Journal open