Sedimentation rates across Baffin Bay since the last glacial period (based on radiocarbon age control)

Around Baffin Bay, the large continental Laurentide, Innuitian, and Greenland ice sheets retreated from their maximum extent reaching the shelf break during the Last Glacial Maximum (LGM) to their present-day close-to-minimum extent being largely confined to onshore settings. The associated changes in ice extent, erosion patterns, and material transport modes probably greatly affected spatial and temporal patterns of sediment deposition in Baffin Bay. While for many sites in Baffin Bay, local information about temporal changes in sedimentation rates exist, a spatial analysis allowing to compare sedimentation patterns is still lacking. To fill this gap, radiocarbon ages from over 50 sediment cores (with two or more dates) across Baffin Bay were compiled to assess the spatiotemporal variability in sediment input to Baffin Bay since the LGM. Preliminary results evaluating sedimentation rates (calculated from un-calibrated 14C ages) binned to 1 ka time slices reveal that during the LGM and the early deglacial, the slope beyond the shelf break and the deep basin were the only active depocenters, however, marked by very low sedimentation rates (mainly <20 cm ka-1), suggesting a largely ice-covered bay. At ~15 ka, sediment supply to these settings increased, likely reflecting the onset of ice retreat during the deglaciation. With the beginning of deposition on the mid and outer shelves after ~10 ka, deposition on the slopes and in the basin ceased almost completely. Ongoing ice retreat progressively uncovered new depocenters in the over-deepened shelf troughs off Baffin Island and Greenland, where from ~9 ka onwards, especially the inner shelf off Greenland, experienced elevated sedimentation rates (~100-500 cm ka-1), while Baffin Island fjords received less material (mainly <100 cm ka-1). Most shelf records show a continuous decrease in sedimentation rates since the early Holocene but a few records from the Greenland shelf point to rates picking up over the last two millennia, probably reflecting the Neoglaciation. Sedimentation rates peak after ~6 ka in the wider northern Baffin Bay. These data generally reflect the transition from low glacial to enhanced deglacial sedimentation beyond the shelves, followed by a progressive landward displacement of the main depocenters towards the over-deepened inner shelf troughs. There, sediment input decreased when the ice sheets attained their minimum extent in the mid-Holocene. Only in northernmost Baffin Bay is this trend turned around, with the highest sediment input in the Late Holocene.