Crustal Structure across the Northern Scandinavian margin along the Senja OBS Profile
- 1Istanbul Technical University, Eurasia Institute of Earth Science, Solid Earth Science, Department of Geodynamics, Istanbul, Türkiye (alemdar20@itu.edu.tr)
- 2Centre for Earth Evolution and Dynamics, University of Oslo,Oslo,Norway
- 3SinoProbe Laboratory, Chinese Academy of Geological Sciences, Beijing
- 4China University of Geosciences, School of Earth Sciences, Wuhan, China
- 5GEOMAR Helmholtz Center for Ocean Research, Section of Marine Geodynamics, Kiel, Germany
The Senja onshore-offshore seismic profile is located in the northwestern part of Fennoscandia, extending from onshore Norway into the North Atlantic Ocean. The Fennoscandian lithosphere has been formed by the amalgamation of terranes and microcontinents to an Archean core, primarily during the Palaeoproterozoic. The later Sveconorwegian (Grenvillian) and Caledonian orogenies had strong effect on the western part of Fennoscandia. The Scandia Mountain range extends along the west coast with elevation up to 2500 m, mainly coinciding with the surface outcrops of Caledonian deformed crust. Its location far from any active plate boundary makes this mountain range enigmatic. The offshore continental part of Fennoscandia experienced a long post-Caledonian extensional period for more than 200 My, and it now forms a continental shelf below sea level extending to the continent to ocean transition.
We present a crustal-scale seismic profile along the NW-SE striking Senja OBS Profile in northern Scandinavia between 12°E and 20°E. This profile covers both offshore and onshore domains over a total distance of ~300 km across the Norwegian shelf in the North Atlantic Ocean, Senja Island, and mainland Norway. Airgun shots from the vessel Hakon Mosby were used as sourced for the refraction/wide-angle reflection survey. The dataset includes recordings on 5 ocean bottom seismometers (OBS) on the shelf, slope, and oceanic environment, complemented by 68 onshore stations at 1.3-kilometre intervals. We present a seismic p-wave velocity model derived by ray-tracing modelling of P-wave arrivals along the profile.
The model includes a deep sedimentary basin extending to ~10 kilometres depth with velocities between ca. 2 km/s and 5.10 km/s, which gradually thickens from the coast to its maximum thickness of 10 km about 25 km from the coast. This deep sedimentary basin is very wide (approximately 8 km). Further offshore the sedimentary cover of the shelf and oceanic environment is relatively thin. The upper crustal velocity below the sedimentary sequence has velocities of ~ 6.0 km/s.
How to cite: Alemdar, R. E., Kahraman, M., Shulgin, A., Breivik, A., Artemieva, I., and Thybo, H.: Crustal Structure across the Northern Scandinavian margin along the Senja OBS Profile , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1098, https://doi.org/10.5194/egusphere-egu24-1098, 2024.
