Magmatic development of the outer Vøring margin from seismic data

Breivik, Asbjørn, Faleide, Jan Inge, Mjelde, Rolf, Flueh, Ernst and Murai, Yoshio (2014) Magmatic development of the outer Vøring margin from seismic data Journal of Geophysical Research: Solid Earth, 119 (9). pp. 6733-6755. DOI 10.1002/2014JB011040.

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The Vøring Plateau off mid-Norway is a volcanic passive margin, located north of the East
Jan Mayen Fracture Zone (EJMFZ). Large volumes of magmatic rocks were emplaced during Early Eocene margin formation. In 2003, an ocean bottom seismometer survey was acquired over the margin. One profile crosses from the Vøring Plateau to the Vøring Spur, a bathymetric high north of the EJMFZ. The P wave data were ray traced into a 2-D crustal velocity model. The velocity structure of the Vøring Spur indicates up to 15 km igneous crustal thickness. Magmatic processes can be estimated by comparing seismic velocity (VP) with igneous thickness (H). This and two other profiles show a positive H-VP correlation at the Vøring Plateau, consistent with elevated mantle temperature at breakup. However, during the first 2 Ma magma production was augmented by a secondary process, possibly small-scale convection. From ∼51.5 Ma excess melting may be caused by elevated mantle temperature alone. Seismic stratigraphy around
the Vøring Spur shows that it was created by at least two uplift events, with the main episode close to the Miocene/Pliocene boundary. Low H-VP correlation of the spur is consistent with renewed igneous growth by constant, moderate-degree mantle melting, not related to the breakup magmatism. The admittance function between bathymetry and free-air gravity shows that the high is near local isostatic equilibrium, precluding that compressional flexure at the EJMFZ uplifted the high. We find a proposed Eocene triple junction model for the margin to be inconsistent with observations.

Document Type: Article
Additional Information: WOS:000343874600002
Keywords: Seismics, crustal structure, North Atlantic, Ocean bottom seismometers
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
DOI etc.: 10.1002/2014JB011040
ISSN: 0148-0227
Projects: SALVADORE, Future Ocean
Date Deposited: 28 Oct 2014 10:00
Last Modified: 27 Feb 2018 14:16

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