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| Titel |
Magmatic development of the outer Vøring Margin |
| VerfasserIn |
Asbjorn Breivik, Jan Inge Faleide, Rolf Mjelde, Ernst Flueh, Yoshio Murai |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076091
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| Zusammenfassung |
| 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
on the Vøring and Lofoten margins. One profile crosses from the Vøring Plateau to
the Vøring Spur, an oceanic plateau north of the EJMFZ. The P-wave data were
modeled by ray-tracing in a 2D velocity model of the crust. The process behind
the excess magmatism can be estimated by comparing seismic velocity (VP) with
igneous thickness (H). This profile and two other profiles farther north show a positive
H-VP correlation, consistent with a hot mantle reservoir of finite extent under the
margin at breakup. However, during the first two million years, magma production
appears to be augmented by a secondary process. By 51-51.5 Ma melting may
be caused by elevated mantle temperature alone. Seismic stratigraphy around the
Vøring Spur shows at least two inversion events, with the main episode tentatively in
the Upper Miocene, apparently through igneous growth to create the up to 15 km
crustal thickness. The H-VP correlation of the spur is low, indicating constant and
moderate-degree mantle melting not tied to the breakup magmatism. The admittance function
between bathymetry and free-air gravity shows that the high is near local isostatic
equilibrium, discounting that compressional flexure at the EJMFZ shaped the high. We
also find no evidence for the proposed Early Eocene triple junction in the area. |
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