Topographic evolution and source-to-sink relationships in Western Norway: a multi-method approach

The controversy of the topographic evolution of the mountains in western Norway and the formation of the paleic surface has been discussed by many authors from different disciplines within Earth sciences ( e.g. Nielsen et al. 2009; Gabrielsen et al. 2010; Pedersen et al. 2016). Yet, there is to date no agreement on the matter.

This multidisciplinary project aims to develop a large-scale structural, thermal and geomorphological model for the area situated between the Møre-Trøndelag Fault Complex (MTFC) in the north, the Lærdal-Gjende Fault (LGF) in the east, and the Sognefjord in the south. The chosen area lacks high-resolution data from the above-mentioned disciplines and this work will fill the gap between studies from the Bergen area (e.g. Ksienzyk et al. 2014, 2016; Scheiber & Viola 2018) and the Trondheim region (e.g. Redfield et al. 2004). The results will give important insight into the basement structure offshore and the source-to-sink relationship such as timing and amount of erosion pulses and sediment transport into offshore basins. In addition, the project will produce knowledge about the structures and the development of the Norwegian continental shelf and increase our understanding of the brittle architecture from a region with several historical large landslides.

We will combine several methods to answer the overarching question of how the post-Caledonian Norwegian topography and the landscape features have evolved. Structural analysis using digital elevation models (DEM) and field measurement, combined with K-Ar fault gouge dating and U-Pb geochronology of calcite, will constrain the brittle structural timing and the paleo-stress of the area. From thermochronological methods like Apatite Fission Track dating and (U-Th)/He analysis of apatites, we can study the thermal history of the area. Lastly, we will by field- and DEM- analysis map paleosurfaces and connect these to the results from the above-mentioned methods.

Sources:

Gabrielsen, R.H., Faleide, J.I., Pascal, C., Braathen, A., Nystuen, J.P., Etzelmuller, B. & O’Donnell, S. 2010. Latest Caledonian to Present tectonomorphological development of southern Norway. Marine and Petroleum Geology, 27, 709–723, https://doi.org/10.1016/j.marpetgeo.2009.06.004.

Ksienzyk, A.K., Dunkl, I., Jacobs, J., Fossen, H. & Kohlmann, F. 2014. From orogen to passive margin: constraints from fission track and (U–Th)/He analyses on Mesozoic uplift and fault reactivation in SW Norway. Geological Society, London, Special Publications, 390, 679–702, https://doi.org/10.1144/SP390.27.

Ksienzyk, A.K., Wemmer, K., et al. 2016. Post-caledonian brittle deformation in the Bergen area, West Norway: Results from K–Ar illite fault gouge dating. Norsk Geologisk Tidsskrift, 96, 275–299, https://doi.org/10.17850/njg96-3-06.

Nielsen, S.B., Gallagher, K., et al. 2009. The evolution of western Scandinavian topography: A review of Neogene uplift versus the ICE (isostasy-climate-erosion) hypothesis. Journal of Geodynamics, 47, 72–95, https://doi.org/10.1016/j.jog.2008.09.001.

Pedersen, V.K., Huismans, R.S. & Moucha, R. 2016. Isostatic and dynamic support of high topography on a North Atlantic passive margin. Earth and Planetary Science Letters, 446, 1–9, https://doi.org/10.1016/j.epsl.2016.04.019.

Redfield, T.F., Torsvik, T.H., Andriessen, P.A.M. & Gabrielsen, R.H. 2004. Mesozoic and Cenozoic tectonics of the Møre Trøndelag Fault Complex, central Norway: Constraints from new apatite fission track data. Physics and Chemistry of the Earth, 29, 673–682, https://doi.org/10.1016/j.pce.2004.03.005.

Scheiber, T. & Viola, G. 2018. Complex Bedrock Fracture Patterns: A Multipronged Approach to Resolve Their Evolution in Space and Time. Tectonics, 37, 1030–1062, https://doi.org/10.1002/2017TC004763.