A HIGH-RESOLUTION STUDY OF THE EIRIK DRIFT ACROSS THE LAST DEGLACIATION USING PLANKTONIC AND BENTHIC FORAMINIFERAL PROXIES

The observations of marine proxies have shown that the deep-ocean circulation system during the last glacial was remarkably different than today. Furthermore, these changes have been observed during the abrupt climate changes that punctuated the last deglacial interval, such as Heinrich-1 (H1), the Younger Dryas (YD), and the Bølling-Allerød (BA). The North Atlantic Ocean is a critical area of deep-water formation, therefore understanding the perturbations to the surface and deep-water systems in this region are critical to understanding the mechanisms that control and initiate these abrupt climate changes.

This study conducted downcore planktonic foraminiferal species counts on core 15JPC (2230 m) to further evaluate the rapid climate and water mass changes from the LGM to today, as well as during the rapid climatic events. Core 15JPC was taken from the Eirik Drift (south of Greenland) and was selected for this study due to its expanded section (>2 m) of the last deglaciation and excellent age control with 10 AMS ¹⁴C dates. Geochemical and sedimentological records, including benthic and planktonic δ¹⁸O and δ¹³C records, ice-rafted detritus counts, sedimentation rates, and percent coarse fraction records have been previously generated for this core.

Research is ongoing but preliminary results show the expected trends with cold-water species like Neogloboquadrina pachyderma (sinistral) dominating the record, and warm-water species like Neogloboquadrina pachyderma (dextral) and Globigerina bulloides peaking during warmer events. Abundances remain static in all species at this site through the LGM and H1 and show changes to warmer waters during the BA. Initial results also suggest that the core (15JPC) may have been located near the source of influx during H1 and not during the Younger Dryas as previously thought. The δ¹³C values are consistent with this hypothesis and indicate a greater shutdown in deep water formation during Heinrich-1. Further work is needed to investigate these trends.