HR: 0800h
AN: T41A-0372    [Abstracts]
TI: Implications of a 3D Density and Magnetic Model of the Møre Volcanic Margin Offshore Norway: An Example of a Non-Volcanic Margin Becoming Volcanic.
AU: * Reynisson, R F
EM: reynir.reynisson@ngu.no
AF: Norwegian University of Science and Technology (NTNU), Department of Petroleum Engineering and Applied Geophysics (IPT) S.P.Andersens vei 15A, Trondheim, 7491, Norway
AU: * Reynisson, R F
EM: reynir.reynisson@ngu.no
AF: Geological Survey of Norway (NGU), Leiv Eirikssons vei 39, Trondheim, 7491, Norway
AU: Ebbing, J
EM: joerg.ebbing@ngu.no
AF: Norwegian University of Science and Technology (NTNU), Department of Petroleum Engineering and Applied Geophysics (IPT) S.P.Andersens vei 15A, Trondheim, 7491, Norway
AU: Ebbing, J
EM: joerg.ebbing@ngu.no
AF: Geological Survey of Norway (NGU), Leiv Eirikssons vei 39, Trondheim, 7491, Norway
AU: Osmundsen, P T
EM: per.terje.osmundsen@ngu.no
AF: Geological Survey of Norway (NGU), Leiv Eirikssons vei 39, Trondheim, 7491, Norway
AU: Gernigon, L
EM: laurent.gernigon@ngu.no
AF: Geological Survey of Norway (NGU), Leiv Eirikssons vei 39, Trondheim, 7491, Norway
AB: The Møre volcanic margin as part of the mid-Norwegian margin is one of the world's most extensively studied continental margins. Volcanic margins are considered an end-member of rifted margins and are characterized by transient, voluminous basaltic volcanism that impedes imaging of deeper structures, a feature generally missing on non-volcanic margins. A 3D density and magnetics model constrained by petrophysical and seismic data was constructed to map the main regional structures of the Møre margin. The general trend of the crustal thickness is from about 30 km at the coastline and gets as thin as 2 km in the basin, thickens again below the marginal high and finally tapers off to about 8 km beyond the Continent-Ocean Boundary (COB). The thinnest crust in the basin is spatially correlated to an anomalously dense body in the lower crust. About 90% of the crust immediately overlying this body is thinner than 10 km. This implies a serpentinized origin of the body as observed on the Iberia and Galicia margins. Spatial correlation of thin crust and proposed deep seated sill complexes is also noted in the model. The sill complexes are further correlated to shallower saucer shaped sills and extrusives landward of the marginal high. This implies an igneous origin of the anomalously dense body. We propose an interaction of two main processes to explain the opposing observations on the model: The margin was a non-volcanic margin that experienced considerable amount of thinning in Jurassic-Early Cretaceous times where mantle serpentinization occurred. In Tertiary times continental breakup occurred further to the west and accompanied temperature elevation resulted in melt production at the thinnest crust. We therefore argue that the Møre margin was a non-volcanic margin until the onset of drifting when it acquired the characteristics of a volcanic margin.
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: 2007 Fall Meeting