Routing of western Canadian Plains runoff during the 8.2 ka cold event

Anders E. Carlson, Peter U Clark, Brian A. Haley, Gary P. Klinkhammer

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    The collapse of the Laurentide Ice Sheet over Hudson Bay ∼8.47 ka allowed the rapid drainage of glacial Lake Agassiz into the Labrador Sea, an event identified as causing a reduction in Atlantic meridional overturning circulation (AMOC) and the 8.2 ka cold event. Atmosphere-ocean models simulations based on this forcing, however, fail to reproduce several characteristics of this event, particularly its duration. Here we use planktonic foraminifera U/Ca records to document the routing of western Canadian Plains runoff that accompanied ice-sheet collapse. Geochemical modeling of the ∼7 nmol/mol increase in U/Ca at the opening of Hudson Bay indicates an increase in freshwater discharge of 0.13 ± 0.03 Sverdrups (106 m3 s−1) from routing, a sufficient magnitude to cause an AMOC reduction. We suggest that this routing event suppressed AMOC strength for several centuries after the drainage of Lake Agassiz, explaining multi-centennial climate anomalies associated with the 8.2 ka cold event.
    Original languageEnglish
    Pages (from-to)L14704
    JournalGeophysical Research Letters
    Volume36
    DOIs
    Publication statusPublished - Jul 2009

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