--> Abstract: Structural and Thermal Reconstruction of a Transect across the More Basin, by Sonja Theissen-Krah; #90177 (2013)

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Structural and Thermal Reconstruction of a Transect across the Møre Basin

Sonja Theissen-Krah

The Møre Basin is part of the Norwegian volcanic continental margin that has been formed during multiple rift episodes since the end of the Caledonian orogeny eventually leading to break up during Eocene. The transect across the Møre Basin, used in this study comprises several sub-basins with pre Cretaceous infill that are bounded by low angle normal faults. These sub-basins and structural highs formed prior to the final rift phase, probably during amagmatic extension during Jurassic-Early Cretaceous. The crustal thickness decreases from about 40 km onshore to around 10-12 km with local minima of about 5 km thickness beneath the above mentioned sub-basins. Parts of the basin are underlain by a high velocity crustal body (LCB) which has been imaged under most of the sedimentary basins along the Norwegian continental margin. The occurrence of the LCB beneath the hyperextended inner parts of the Møre Margin has been associated with partial serpentinisation of the mantle during the Jurrasic –Early Cretaceous extension (Doré et al., 1999; Osmundsen and Ebbing, 2008), similar to the observations of the magma poor Iberian margin (Perez-Gussinye et al., 2001). In this study we will reconstruct the thermal and structural evolution of a transect across the Møre Basin with different basin modelling approaches. We use the basin modelling software TecMod2D for structural reconstruction and compare the results with the classical backstripping approach for existing boreholes. The resulting stretching factors from the structural reconstruction can be compared to the estimated stretching derived from crustal thinning. The results are compared with published data and to observations from other transect across the Norwegian margin. Finally we will discuss the possibility of mantle serpentinisation during extension, which can only occur in a certain temperature range (below ~400 °C) and if brittle faulting allows water to penetrate into the mantle. Doré, A.G., Lundin, E.R., Jensen, L.N., Birkeland, O., Eliassen, P.E., Fichler, C., 1999. Principal tectonic events in the evolution of the northwest European Atlantic margin, in: Fleet, A.J., Boldy, S.A.R. (Eds.), Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference. Geological Society, London, pp. 41-61. Osmundsen, P.T., Ebbing, J., 2008. Styles of extension offshore mid-NO and implications for mechanisms of crustal thinning at passive margins. Tectonics 27. Perez-Gussinye, M., Reston, T.J., Phipps Morgan, J., 2001. Serpentinization and magmatism during extension at non-volcanic margins: the effect of initial lithospheric structure. Geological Society, London, Special Publications 187, 551-576.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013