Geochemical and isotopic tracers of Arctic sea ice sources and export with special attention to the Younger Dryas interval

• Published in: Quaternary Science Reviews
• Main Authors: Maccali, Jenny, Not, Christelle, Poirier, André, Hillaire-Marcel, Claude
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Meltwater; Sea-ice; Younger Dryas; Isotopes; Arctic; Svalbard; Beaufort Sea; Fram Strait; Ice Sheet; Lomonosov Ridge; Sea ice
• Online Access: https://doi.org/10.1016/j.quascirev.2013.05.001; http://hdl.handle.net/10722/210089

Radiogenic isotopes (Sr, Nd) in Ice Rafted Debris (IRD) sediments from the Lomonosov Ridge and Fram Strait Arctic areas are used to document changes in Arctic sea-ice sources and trajectories since the Last Glacial Maximum (LGM). The two records provide evidence for enhanced sea-ice production in the Beaufort Sea and its subsequent export through Fram Strait during the Younger Dryas (YD) interval. This pattern, exclusive to the YD, followed an LGM-Bølling-Allerød interval, when multiyear and/or reduced sea-ice mobility resulted in sedimentary hiatuses in the Central Arctic. Meanwhile, IRD from Svalbard-Barents ice-sheet margin source were still deposited in the Fram Strait area. The "isotopic excursion" of the YD points to enhanced sea-ice production in the Beaufort Sea, which we link to the Lake Agassiz (?)/Laurentide ice sheet drainage event through the Mackenzie route. Following this event, the Holocene depicts a 5-fold reduction in IRD rates with a shift towards prominent sea-ice production along Russian shelves. From a methodological viewpoint, we demonstrate that radiogenic isotopes must be used in a multi-proxy approach to better constrain IRD and sea-ice sources and routes. From a paleoceanographic perspective, we conclude that an Arctic freshwater/sea-ice export route should now be seen as the most likely mechanism for an AMOC reduction during the YD in accordance with more recent improved model experiment. © 2013 Elsevier Ltd. Link_to_subscribed_fulltext