Multi-proxy paleoenvironmental reconstruction of Robertson Bay, East Antarctica, since the last glacial period

• Published in: Quaternary Science Reviews
• Main Authors: Torricella, Fiorenza, Truax, Olivia, Morelli, Danilo, Battaglia, Francesca, Corradi, Nicola, Crosta, Xavier, de Santis, Laura, Etourneau, Johan, Finocchiaro, Furio, Gallerani, Andrea, Geniram, Andrea, Giglio, Federico, Ginnane, Catherine, Levy, Richard, Miserocchi, Stefano, Morigi, Caterina, Pochini, Enrico, Riesselman, Christina, Turnbull, Jocelyn, Colizza, Ester
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: Robertson bay; Antarctica; Sedimentary facies; Diatoms; Ramped pyrolysis oxidation; [SDE]Environmental Sciences; Antarc*; Antarctic; East Antarctica; Ice Shelf; Ross Sea; Sea ice; Southern Ocean
• Online Access: https://hal.science/hal-04634101; https://doi.org/10.1016/j.quascirev.2024.108629

International audience Antarctic fjords and coastal bays are excellent traps for sediment and represent key areas for high-resolutioninvestigation of past environmental conditions. Robertson Bay is an understudied coastal area located at theconfluence of the Ross Sea and the Southern Ocean. Recently obtained seafloor morphology data indicate thepresence of a cross-shelf elongated valley, composed of three minor basins separated by sills and seabed ridgeswith an arcuate shape. Several cores were collected within the basins, and investigated using a multiproxyapproach including sedimentological, chemical, geochemical, and micropaleontological characterization toreconstruct the paleoenvironmental evolution from the last glacial period to present. The ages of two of thesecores are constrained using ramped pyrolysis oxidation radiocarbon dating. Four sedimentary facies were recognisedfrom which we developed a sedimentary model covering the last 21,000 years (21 ka BP). Our recordprovide evidence for a covering ice shelf cover from 21 to 16.5 ka BP, which gradually receded between 16,5 and11 ka BP due to the progressive intrusion of modified Circumpolar Deep Water, thereby promoting the formationof Ice Shelf Water and High Salinity Shelf Water. From 11 to 5,8 ka BP, the ice shelf continued shrinking andnutrient-rich of modified Circumpolar Deep Water penetration onto the continental shelf progressively favoureddiatom blooms and a general increase in primary productivity until 5.8 ka BP. The Late Holocene is characterisedby an alternation of prolonged sea ice cover with stratified water column and strong bottom current with prolongedsea-ice free season with the intrusion of modified Circumpolar Deep Water and very slow energy bottomcurrent.