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dc.contributor.authorParker, RL
dc.contributor.authorFoster, GL
dc.contributor.authorGutjahr, M
dc.contributor.authorWilson, PA
dc.contributor.authorLittler, KL
dc.contributor.authorCooper, MJ
dc.contributor.authorMichalik, A
dc.contributor.authorMilton, JA
dc.contributor.authorCrocket, KC
dc.contributor.authorBailey, I
dc.date.accessioned2022-07-13T10:21:35Z
dc.date.issued2022-05-25
dc.date.updated2022-07-12T17:48:40Z
dc.description.abstractUnderstanding the history of continental ice-sheet growth on North America, and in particular that of the Laurentide Ice Sheet (LIS), is important for palaeoclimate and sea-level reconstructions. Information on ice-sheet extent pre-dating the Last Glacial Maximum (LGM) is heavily reliant, though, on the outputs of numerical models underpinned by scant geological data. Important aspects of LIS history that remain unresolved include the timing of its collapse during Termination 2, the first time that it expanded significantly during the Last Glacial Cycle, and whether its volume was significantly reduced during marine isotope stage (MIS) 3. To address these issues and more, we present authigenic iron-manganese (Fe–Mn) oxyhydroxide-derived high-resolution records of Pb isotope data and associated rare earth element profiles for samples spanning the past ∼130 kyr from northwest North Atlantic Labrador Sea, IODP Site U1302/3. We use these new data to track chemical weathering intensity and solute flux to the Labrador Sea associated with LIS extent on the adjacent highly radiogenic (high Pb isotope composition) North American Superior Province (SP) craton since the Penultimate Glacial Maximum (PGM). Our new records show that relatively high (radiogenic) values characterise warm marine isotope stages (MIS) 5, 3 and 1 and the lowest (most unradiogenic) values occurred during cold stages MIS 6, 4 and 2. The radiogenic Pb isotope excursion associated with Termination 2 is short-lived relative to the one documented for Termination 1, suggesting that LIS retreat during the PGM was relatively fast compared to the LGM and that its collapse during the last interglacial occurred ∼125 ka. Highly radiogenic inputs to the Labrador Sea during MIS 5d-a, ∼116–71 ka, most likely reflect a spin-up in Labrador Current vigour, incipient glaciation and renewed glacial erosion of high grounds of the eastern SP craton by localised wet-based ice-caps. A large decrease in Pb isotope values towards unradiogenic LGM-like compositions between ∼75–65 ka across the MIS 5/4 transition likely reflects a slow-down in Labrador Current vigour, an increase in subaerial deposition of aeolian dust and a significant advance of the LIS across Hudson Bay caused a strong reduction or even abandonment of Pb sourcing from the SP. The relatively radiogenic Pb isotope composition of bottom-waters bathing our study site during MIS 3, 57–29 ka, is unlikely to support a recently proposed major reduction in LIS extent for this time. Instead, we argue these values are better explained by southern Greenland Ice Sheet retreat, increased chemical weathering of the Ketelidian Mobile Belt and subsequent Pb runoff from Greenland.en_GB
dc.description.sponsorshipNatural Environment Research Councilen_GB
dc.description.sponsorshipRoyal Society (Wolfson Merit Award)en_GB
dc.format.extent107564-
dc.identifier.citationVol. 287, article 107564en_GB
dc.identifier.doihttps://doi.org/10.1016/j.quascirev.2022.107564
dc.identifier.grantnumberNE/K014137/1en_GB
dc.identifier.urihttp://hdl.handle.net/10871/130239
dc.language.isoenen_GB
dc.publisherElsevieren_GB
dc.rights© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).en_GB
dc.subjectQuaternaryen_GB
dc.subjectPaleoceanographyen_GB
dc.subjectNorth Atlanticen_GB
dc.subjectLast Glacial Cycleen_GB
dc.subjectLabrador Currenten_GB
dc.subjectContinental runoffen_GB
dc.subjectChemical weatheringen_GB
dc.subjectRare earth elementsen_GB
dc.subjectFe–Mn oxyhydroxidesen_GB
dc.titleLaurentide Ice Sheet extent over the last 130 thousand years traced by the Pb isotope signature of weathering inputs to the Labrador Seaen_GB
dc.typeArticleen_GB
dc.date.available2022-07-13T10:21:35Z
dc.identifier.issn0277-3791
exeter.article-number107564
dc.descriptionThis is the final version. Available from Elsevier via the DOI in this record. en_GB
dc.descriptionData availability: The new IODP Site U1302/3 data presented and compiled Superior Province Pb isotope data are available in the attached Excel spreadsheets. Supplement 1 and 2 is also deposited in PANGAEA.en_GB
dc.identifier.journalQuaternary Science Reviewsen_GB
dc.relation.ispartofQuaternary Science Reviews, 287
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en_GB
dcterms.dateAccepted2022-05-10
rioxxterms.versionVoRen_GB
rioxxterms.licenseref.startdate2022-05-25
rioxxterms.typeJournal Article/Reviewen_GB
refterms.dateFCD2022-07-13T10:18:19Z
refterms.versionFCDVoR
refterms.dateFOA2022-07-13T10:23:16Z
refterms.panelBen_GB
refterms.dateFirstOnline2022-05-25


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© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Except where otherwise noted, this item's licence is described as © 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).