Beryllium isotope variations recorded in the Adélie Basin, East Antarctica reflect Holocene changes in ice dynamics, productivity, and scavenging efficiency

• Published in: Quaternary Science Advances
• Main Authors: Behrens, Bethany C., Yokoyama, Yusuke, Miyairi, Yosuke, Sproson, Adam D., Yamane, Masako, Jiménez-Espejo, Francisco J., McKay, Robert M., Johnson, Katelyn M., Escutia, Carlota, Dunbar, Robert B.
• Other Authors: European Commission, Japan Society for the Promotion of Science, Ministerio de Ciencia e Innovación (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier BV 2022
• Subjects: Holocene; East Antarctica; Cosmogenic nuclides; Beryllium isotopes; Scavenging; Antarctic; East Antarctic Ice Sheet; New Zealand; The Antarctic; Wilkes Subglacial Basin; Antarc*; Antarctica; Ice Sheet; Ice Shelf
• Online Access: http://hdl.handle.net/10261/334090; https://doi.org/10.1016/j.qsa.2022.100054

The Adélie Basin is a relatively small (∼1600 km), semi-enclosed continental shelf bathymetric depression located adjacent to the Wilkes Subglacial Basin, a basin underlying a sector of the East Antarctic Ice Sheet that contains ∼3–4 m sea level equivalent of ice. Located within the Adélie Basin is a ∼184 m thick laminated sediment deposit, the Adélie Drift, ideal for examining regional changes in ice sheet and ocean dynamics. Here, we examine the ratio of reactive beryllium-10 to reactive beryllium-9 ((Be/Be)) in a marine sediment core obtained from the Adélie Drift to assess these changes during the Holocene epoch (11.7 ka BP to present). The (Be/Be) record provides insight into changes in freshwater input, primary productivity, and scavenging efficiency, while removing the influence of particle size on Be concentration. During the early Holocene, (Be/Be) ratios indicate increased meltwater discharge from ca. 11.7 to 10 ka BP, as grounded ice retreated from the Adélie Basin and adjacent bathymetric highs. After ∼10 ka BP, beryllium isotopes are influenced by scavenging efficiency and dilution controlled by ocean currents and accumulation rate, operating alongside meltwater input, suggesting there are additional factors to consider when using (Be/Be) as a proxy for ice shelf cover and glacial dynamics. Financial support for this study was provided by the Japan Society for the Promotion of Science ( JSPS ) KAKENHI ( 20H00193 ) to YY, JSPS Fellowship DC1 ( 20J21145 ) to BCB, and JSPS Post-Doctoral Fellowship (PE17712 and P18791) to ADS . RM was funded by the New Zealand Ministry of Business, Innovation and Employment through the Antarctic Science Platform ( ANTA1801 ). CE and FJJ-E acknowledges funding through Spanish Ministry of Science and Innovation (grant CTM2017-89711-C2-1-P ), co-funded by the European Union through FEDER funds.