Depth-dependent Stretching on the Lofoten, Vøring and Møre Rifted Margins: Implications for Subsidence and Hydrocarbon Maturation

• Main Authors: Nick Kusznir, Alan Roberts, Rob Hunsdale
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Lofoten
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.430.440; http://www.searchanddiscovery.com/abstracts/pdf/2002/hedberg_norway/extended/ndx_kusznir.pdf

Reverse and forward structural-and-stratigraphic modelling show that depth-dependent stretching occurs on the outer part of the Norwegian rifted margin. Subsidence analysis shows substantial thinning of the continental lithosphere within ~ 100 – 150 km of the COB, while the upper crust shows no significant faulting and extension at breakup or immediately preceding breakup in the Palaeocene. For the Lofoten Margin β stretching-factors approaching infinity are required at ~ 54 Ma west of the Utrøst Ridge to restore Top Basalt and the Top Tåre to presumed sub-aerial depositional environments. Breakup age β stretching-factors are predicted to rapidly reduce towards the east of the Utrøst Ridge. For the Vøring margin, south of the Bivrøst Transform and Lineament System, β stretching-factors of ~ 1.8 to 2.5 are needed to restore Top Basalt and Top Tåre to sea level (see Roberts et al 1997 also). Again no similar magnitude of extension by faulting is observed in the upper crust. These observations can be continued southwards into the northern Møre Basin. For the mid-Lofoten margin an additional Eocene crustal thinning event younger than 54 Ma is required to explain observed subsidence. The absence of significant Palaeocene extension on the Lofoten and Vøring margins, and the additional Eocene subsidence and faulting, implies that