Hunting paleoceanographic archives of ice sheet-ocean interaction in the northwestern Ross Sea, Antarctica

• Published in: Frontiers in Earth Science
• Main Authors: Sookwan Kim, Laura De Santis, Jong Kuk Hong, Ester Colizza, Sunghan Kim, Andrea Bergamasco, Sang-Hoon Lee, Seung-Goo Kang, Min Kyung Lee, Hyoungjun Kim, Yeonjin Choi, Andrea Geniram, Hyoung Gyu Choi, Jae Il Lee, Kyu-Cheul Yoo, Yongcheol Park
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2023
• Subjects: contourite; bottom current; Antarctica; Ross Sea; seismic stratigraphy; seafloor morphology; Science; Q; Central Basin; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.3389/feart.2023.1234347; https://doaj.org/article/c3f90a16054a449f8f2c82f5d091e44d

The analysis of sedimentary deposits influenced by bottom currents in glaciated continental margins provides crucial insights into paleo-depositional and oceanographic conditions. These reconstructions enable the assessment of interactions between advance and retreat of grounded ice sheets and past ocean circulation patterns. However, questions regarding these interactions and their specific mechanisms remain largely unanswered due to a lack of data in this remote area. In this study, we conducted a comprehensive analysis by integrating marine geophysical data, surficial sediment cores, oceanographic measurements, and ocean circulation models. Our aim was to understand spatial and temporal variations in sedimentary and oceanographic conditions during the past glacial and interglacial periods in combination with the long-term stratigraphic evolution. By integrating and cross-referencing diverse datasets, we were able to infer how bottom-current-controlled deposits (i.e., contourites) developed along the western bathymetric high of the Central Basin in the northwestern Ross Sea margin, Antarctica. Contouritic deposits lying over and along the flanks of bathymetric highs were identified through their mound-shaped external geometry and acoustically stratified facies, characterized by reflectors pinching toward the moat. Acoustic facies and multi-beam backscatter results, in conjunction with sedimentary core data, revealed contrasting patterns. Bathymetric highs exhibited thin (<10 m thick) coarser-grained sedimentary layers with higher backscatter, while the lower slope and rise displayed thick (>10 m thick), finer-grained stratified sediments with lower backscatter. These findings indicate that seabed winnowing occurred by strong bottom current during past glacial periods as supported by sedimentological analysis. The pathways of the westward-deflected dense shelf water outflow and the westward-flowing along-slope current, as simulated by oceanographic models, explain the distinctive development of ...