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Routing of western Canadian Plains runoff during the 8.2 ka cold event
Author(s) -
Carlson Anders E.,
Clark Peter U.,
Haley Brian A.,
Klinkhammer Gary P.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl038778
Subject(s) - bay , geology , surface runoff , foraminifera , oceanography , ice sheet , climatology , routing (electronic design automation) , ecology , biology , computer network , computer science , benthic zone
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 (10 6 m 3 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.