Pliocene–Pleistocene warm-water incursions and water mass changes on the Ross Sea continental shelf (Antarctica) based on foraminifera from IODP Expedition 374

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dc.citation.firstpage211en_US
dc.citation.issueNumber2en_US
dc.citation.journalTitleJournal of Micropalaeontologyen_US
dc.citation.lastpage238en_US
dc.citation.volumeNumber43en_US
dc.contributor.authorSeidenstein, Julia L.en_US
dc.contributor.authorLeckie, R. Marken_US
dc.contributor.authorMcKay, Roberten_US
dc.contributor.authorDe Santis, Lauraen_US
dc.contributor.authorHarwood, Daviden_US
dc.contributor.authorIODP Expedition 374 Scientistsen_US
dc.date.accessioned2024-08-29T21:11:48Zen_US
dc.date.available2024-08-29T21:11:48Zen_US
dc.date.issued2024en_US
dc.description.abstractInternational Ocean Discovery Program (IODP) Expedition 374 sailed to the Ross Sea in 2018 to reconstruct paleoenvironments, track the history of key water masses, and assess model simulations that show warm-water incursions from the Southern Ocean led to the loss of marine-based Antarctic ice sheets during past interglacials. IODP Site U1523 (water depth 828 m) is located at the continental shelf break, northeast of Pennell Bank on the southeastern flank of Iselin Bank, where it lies beneath the Antarctic Slope Current (ASC). This site is sensitive to warm-water incursions from the Ross Sea Gyre and modified Circumpolar Deep Water (mCDW) today and during times of past warming climate. Multiple incursions of subpolar or temperate planktic foraminifera taxa occurred at Site U1523 after 3.8 Ma and prior to ∼ 1.82 Ma. Many of these warm-water taxa incursions likely represent interglacials of the latest Early Pliocene and Early Pleistocene, including Marine Isotope Stage (MIS) Gi7 to Gi3 (∼ 3.72–3.65 Ma), and Early Pleistocene MIS 91 or 90 (∼ 2.34–2.32 Ma) and MIS 77–67 (∼ 2.03–1.83 Ma) and suggest warmer-than-present conditions and less ice cover in the Ross Sea. However, a moderately resolved age model based on four key events prohibits us from precisely correlating with Marine Isotope Stages established by the LR04 Stack; therefore, these correlations are best estimates. Diatom-rich intervals during the latest Pliocene at Site U1523 include evidence of anomalously warm conditions based on the presence of subtropical and temperate planktic foraminiferal species in what likely correlates with interglacial MIS G17 (∼ 2.95 Ma), and a second interval that likely correlates with MIS KM3 (∼ 3.16 Ma) of the mid-Piacenzian Warm Period. Collectively, these multiple incursions of warmer-water planktic foraminifera provide evidence for polar amplification during super-interglacials of the Pliocene and Early Pleistocene. Higher abundances of planktic and benthic foraminifera during the Mid- to Late Pleistocene associated with interglacials of the MIS 37–31 interval (∼ 1.23–1.07 Ma), MIS 25 (∼ 0.95 Ma), MIS 15 (∼ 0.60 Ma), and MIS 6–5e transition (∼ 0.133–0.126 Ma) also indicate a reduced ice shelf and relatively warm conditions, including multiple warmer interglacials during the Mid-Pleistocene Transition (MPT). A decrease in sedimentation rate after ∼ 1.78 Ma is followed by a major change in benthic foraminiferal biofacies marked by a decrease in Globocassidulina subglobosa and a decrease in mud (< 63 µm) after ∼ 1.5 Ma. Subsequent dominance of Trifarina earlandi biofacies beginning during MIS 15 (∼ 600 ka) indicate progressive strengthening of the Antarctic Slope Current along the shelf edge of the Ross Sea during the mid to Late Pleistocene. A sharp increase in foraminiferal fragmentation after the MPT (∼ 900 ka) and variable abundances of T. earlandi indicate higher productivity, a stronger but variable ASC during interglacials, and/or corrosive waters, suggesting changes in water masses entering (mCDW) and exiting (High Salinity Shelf Water or Dense Shelf Water) the Ross Sea since the MPT.en_US
dc.identifier.citationSeidenstein, J. L., Leckie, R. M., McKay, R., De Santis, L., Harwood, D., & IODP Expedition 374 Scientists. (2024). Pliocene–Pleistocene warm-water incursions and water mass changes on the Ross Sea continental shelf (Antarctica) based on foraminifera from IODP Expedition 374. Journal of Micropalaeontology, 43(2), 211–238. https://doi.org/10.5194/jm-43-211-2024en_US
dc.identifier.digitaljm-43-211-2024en_US
dc.identifier.doihttps://doi.org/10.5194/jm-43-211-2024en_US
dc.identifier.urihttps://hdl.handle.net/1911/117736en_US
dc.language.isoengen_US
dc.publisherCopernicus Publicationsen_US
dc.rightsExcept where otherwise noted, this work is licensed under a Creative Commons Attribution (CC BY) license.  Permission to reuse, publish, or reproduce the work beyond the terms of the license or beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en_US
dc.titlePliocene–Pleistocene warm-water incursions and water mass changes on the Ross Sea continental shelf (Antarctica) based on foraminifera from IODP Expedition 374en_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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