Cenozoic tectonostratigraphy and pre-glacial erosion: A mass-balance study of the northwestern Barents Sea margin, Norwegian Arctic. (September 2018)

• Record Type: Journal Article
• Authors: Lasabuda, Amando; Laberg, Jan Sverre; Knutsen, Stig-Morten; Safronova, Polina
• Is Part Of: Journal of geodynamics. Volume 119(2018)
• Page Start: 149
• Page End: 166
• Publication Date: 2018-09
• Subjects: Northwestern Barents Sea -- Cenozoic -- Tectonic -- Mass-balance -- Erosion -- Sedimentation; Geodynamics -- Periodicals; Earth movements -- Periodicals; Rock deformation -- Periodicals; Earth -- Internal structure -- Periodicals; 551.1
• DOI: 10.1016/j.jog.2018.03.004
• Languages: English
• ISSNs: 0264-3707

Abstract

Graphical abstract: Highlights: The evolution of the NW Barents Sea continental margin has been reconstructed to quantify the sedimentation and erosion during the Paleogene–Neogene. The average sedimentation rate for the Paleogene–Neogene is about 0.034 m/k.y. The average net erosion and erosion rate for the sediment source area to be ∼2440 m and 0.038 m/k.y, respectively. The erosion rate is two times higher compared to the adjacent SW Barents Sea margin, probably reflecting erosion of a more tectonically active NW margin. This study suggests more than half of the Cenozoic erosion affecting the studied part of the NW Barents Sea was of pre-glacial origin. Abstract: The evolution of the northwestern Barents Sea continental margin, part of a NW-SE trending mega shear zone, has been reconstructed in order to quantify the sedimentation and erosion affecting this area during and after its formation in the Paleogene–Neogene. This development was closely related to the sea-floor opening of the Norwegian-Greenland Sea. Our study incorporated 2D seismic data, well data, and information from shallow cores. During the Paleocene–Eocene, the northwesternmost Barents Sea margin was subjected to compression-transpression that led to the development of the West Spitsbergen Fold-Thrust Belt (WSFTB) and largely affected the northern part of the study area. To the south, the Vestbakken volcanic province developed in a pull-apart setting. A transition zone separates these two areas marked by a basin morphology becoming more pronounced to the south suggesting increasing subsidence and extension. Subsequently, during the Oligocene, extension and sea-floor spreading were initiated along the whole margin, resulting in the opening of the Fram Strait between Spitsbergen and NE Greenland in the Miocene. During the Paleocene, the Stappen High and a part of the NE Greenland shelf sourced sediments into the newly developing basins. The southwestern part of the WSFTB, the Stappen High, and part of the NE Greenland margin are interpreted as the main sediment source areas in the Eocene. During the Oligocene and Neogene, a larger part of the northwestern Barents Sea shelf is interpreted to have acted as source area including the Edgeøya platform. As a result of this development, the wider Barents Sea shelf itself is inferred to have been a lowland prior to the northern hemisphere glaciations. We found that the average sedimentation rate for the Paleogene–Neogene at the northwestern Barents Sea margin is about 0.034 m/k.y. This number is in agreement with the sedimentation rate reported from present-day fluvial systems and modern rates coastal erosion. By using a mass-balance approach, we have also estimated the average net erosion and erosion rate for the Paleogene–Neogene period to be ∼2440 m and 0.038 m/k.y, respectively. This erosion rate is two times higher compared to the southwestern Barents Sea margin, probably reflecting erosion of a more tectonically active northwestern margin. Thus, for the western Barents Sea margin, a general increasing trend of pre-glacial erosion northwards can be inferred. This study also suggests that more than half of the Cenozoic erosion affecting the studied part of the northwestern Barents Sea were of pre-glacial origin.