Geophysical and geological investigation of the Tampen Slide and its relationship with the Aegir Ridge: Origin, extent and frequency of submarine mass wasting offshore Norway

• Applicant: Dr. Rachel Barrett
• Subject Area: Geophysics ; Geology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501223115

Submarine landslides can have devastating effects on seafloor and coastal infrastructure and ecology, and can result in potentially destructive tsunami waves. In spite of this, many questions regarding their frequency, preconditioning and triggering factors remain unanswered. Offshore Norway, giant volume submarine landslides (‘mega-slides’), which can be orders of magnitude larger than terrestrial landslides, are thought to occur once per glacial cycle (100 kyr). The timing of the giant Storegga Slide is well constrained to 8.1 kyr BP, and its predecessor, the Tampen Slide, was thought to have occurred 130 kyr ago. Recent work by colleagues in the UK, however, provides evidence of a large-volume turbidite in the Aegir Ridge north of Norway that occurred at 55-60 ka. Based on its stratigraphic position, they link this mega-turbidite to the Tampen Slide. In order to further investigate and prove this, high-resolution acoustic (Parasound, multi-beam bathymetry, and seismic) data and sediment gravity cores were collected during cruise MSM98/2 in early 2021. These data link the headwall region of the Tampen Slide with the Aegir Ridge, and record a long history of mass wasting both within and adjacent to the Aegir Ridge. Using the data collected during MSM98/2, this project will test the hypothesis that the Tampen Slide occurred at 55-60 ka and is much younger than previously postulated, thereby challenging the model that large landslides on the Norwegian continental margin (and other glaciated margins) only occur after major glaciations. Furthermore, we will also investigate whether multiple large tsunamigenic landslides are recorded by large volume turbidites in a newly-cored basin adjacent to the Aegir Ridge. Constraining the ages and source locations of the turbidites and debris flows within and adjacent to the Aegir Ridge will provide crucial information about the frequency, possible volumes and sources of mass wasting in the region, as well as their ultimate hazard potential. The MSM98/2 sediment cores and acoustic data have undergone preliminary processing and analysis, but fully understanding the frequency and source(s) of turbidite flows, and the impact of glacial processes on sedimentation within the Aegir Ridge, as well as the relationship between the Aegir Ridge turbidites and the Tampen Slide, requires further, more detailed processing (acoustic data); compositional analysis (chemical and physical properties of the cores); and dating. The MSM98/2 data will be integrated with existing data supplied by project partners to develop a regional stratigraphic model for the Aegir Ridge.

• DFG Programme: Research Grants
• International Connection: Norway, United Kingdom
• Co-Investigators: Dr. Felix Gross; Professor Dr. Sebastian Krastel; Dr. Jens Schneider von Deimling
• Cooperation Partners: Professor Dr. Haflidi Haflidason; Dr. James Hunt; Professor Dr. Peter Talling