New insights into marine-based paleo-ice sheet dynamics and glaciomarine depositional environment in an interfan area between ice stream-derived trough mouth fans, off west Svalbard

Abstract

Understanding the dynamic history of the marine-based paleo-Svalbard Ice Sheet provides critical insights into past climate change and the interactions between the ocean system and the cryosphere. High-resolution seismic imaging is needed to decipher the glacial history of the western Svalbard continental margin, which has experienced multiple glaciations throughout the Quaternary period. Glaciomarine sediments preserved on the continental margin provide a detailed record of these events. We integrate high-resolution airgun seismic (vertical resolution 5 m), and deep-towed transducer seismic data (vertical and horizontal resolutions 1 and 3 m, respectively) along with age constraints derived from a piston core to determine the seismic stratigraphic framework, depositional architecture, and sedimentation processes of the interfan area between the Kongsfjorden and Isfjorden Trough Mouth Fans (TMFs). Age constraints from seafloor drilling indicate that the build-up of the Kongsfjorden TMF began around 1.2 million years ago. Our data analysis reveals four distinct shelf-edge glaciations during the Weichselian period, dated at 120–110 ka, ∼90 ka, 61–54 ka, and ∼24 ka. These glacial units on the upper continental slope contain debris materials transported by slow-moving ice sheets. During maximum glacial expansion, iceberg calving created V-shaped indentations, and glaciogenic debris flows carved erosional troughs. Seismic interpretation and debris flow modeling aided in understanding the development of lensoid debris morphology, stacking patterns, and the evolution of debris lobes resulting from local variations in bottom topography. This study underscores the value of using multiple high-resolution seismic data sources to enhance our understanding of the glacial history and depositional processes in the interfan region.