GSA QUATERNARY GEOLOGY AND GEOMORPHOLOGY DIVISION KIRK BRYAN AWARD - THE DYNAMIC ROLE OF THE PACIFIC OCEAN AND CORDILLERAN ICE SHEET IN MILLENNIAL-SCALE GLOBAL CLIMATE VARIABILITY

In recent years we have seen an intensification of research on the expression of global millennial-scale climate perturbations of the last ice age in the Pacific basin. The data collected through these efforts is illuminating the probable active role of the Pacific, which comprises the largest heat sink as well as geologically ‘active’ reservoir of carbon on Earth, in modulating, propagating, and perhaps even generating events of abrupt global climate change. These Pleistocene observations are inextricably intertwined with the stability of the largest Pacific cryosphere system: the Cordilleran Ice Sheet of Western North America. Here we review new radiocarbon and sedimentological results from the Gulf of Alaska that document recurrent episodes of reorganized Pacific Ocean circulation synchronous with rapid discharge from the Cordilleran Ice Sheet. These Pacific episodes of abrupt retreat of marine-terminating outlet glaciers, termed ‘Siku Events’ repeatedly lead similar episodes of Atlantic ice sheet instability known as ‘Heinrich Events’ over the past ~45,000 years. We explore the apparent cascade of global climate perturbations supported by the best available chronologies for these records, as well as the implications for potential drivers of ice sheet instability in both the Pacific and Atlantic.