Geochemical constraints on the Laurentide Ice Sheet contribution to Meltwater Pulse 1A

• Main Author: Anders E Carlson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Antarctic; Arctic; Arctic Ocean; The Antarctic; Antarc*; Ice Sheet; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1081.8053; http://geoscience.wisc.edu/geoscience/wp-content/uploads/2010/07/carlson_2009_qsr.pdf

a b s t r a c t Planktonic and benthic d 18 O records adjacent to the runoff outlets of the Laurentide Ice Sheet (LIS) indicate that the LIS contributed to the abrupt w20 m rise in sea level w14.6 ka, Meltwater Pulse 1A (MWP-1A). However, the magnitude of the LIS contribution still remains unresolved. Here, I use a freshwater runoff-ocean mixing model to calculate the LIS meltwater required to explain the decreases in planktonic and benthic d 18 O observed during MWP-1A at the southern, eastern and northern runoff outlets of the LIS. Maximum LIS contributions in equivalent sea level rise for a 500-year long MWP-1A are 2.7 m discharged into the Gulf of Mexico as a combined hyperpycnal and hypopycnal flow, 2.1 m discharged into the North Atlantic, and 0.5 m into the Arctic Ocean, for a total LIS contribution of 5.3 m. A LIS contribution of <30% to MWP-1A supports the hypothesis that a significant component of this MWP was sourced from the Antarctic Ice Sheet.