| dc.description.abstract | Utsira Nord offshore wind farm area, located within the Norwegian Channel, less than 10 km west of Utsira island, is designated to host floating wind turbines for renewable energy production. The Norwegian Channel has been subjected to multiple ice advances throughout the last 1,1 million years, with the last Glacial Maximum (LGM) marking the final major glaciation reaching the Norwegian Channel between 25 and 21 ka. This thesis aims to map the glacimarine sediments present in the Utsira Nord area and discuss their properties and depositional environments. Furthermore, the aim is to use this data to estimate the time Utsira Nord became ice-free during the last deglaciation. The foundation of the study relies on the use of 2D TOPAS data and data from a sediment piston core obtained during the scientific cruise GS22-241 in the summer of 2022. Through different laboratory methods and seismic interpretation, three distinct seismic units are identified and denoted as SU1, SU2, and SU3.
The seismic units correlate with the lithostratigraphic found in GS22-241-14PC which is denoted as L1, L2, and L3. These units are interpreted to represent meltwater plumites deposited under varying proximal and distal ice conditions.
Based on radiocarbon dating alongside modelled dates and reference dates, Utsira Nord became ice-free around 16,7 ka BP. Geomorphological observations divide Utsira Nord into an eastern part containing a trough-like embayment, serving as a depositional basin for meltwater plumes, and a western part characterized by iceberg ploughing resulting in a rugged surface. Relative strong Holocene currents have, based on observations from seismic stratigraphy and lithostratigraphy, eroded the soft Holocene sediments at the top of the coring site. Such currents can pose challenges for offshore wind foundations due to scouring. | |
