Sedimentary Records of the Evolution of the Melville Bugt Ice Stream

In response to ongoing climate forcing the Greenland Ice Sheet (GrIS) has experienced changes in extent and mass balance, with implications for sea level and oceanography of the North Atlantic. Given that the GrIS has the potential to add up to ~7 m to global sea-level, and that over ~150 million people live within just 1 m of current sea-level, understanding the long-term history of the ice sheet is of global societal significance. A full understanding of past GrIS dynamics in response to climate change is key to modelling and projecting future scenarios.
There is an increasing volume of data from studies of the Last Glacial Maximum (LGM) and Younger Dryas GrIS extent and retreat dynamics, but these data are heavily skewed towards Jakobshavn Isbræ in Disko Bugt, West Greenland. Outside this region there is a less well developed understanding of the timing and dynamics of deglaciation. For example, the seafloor of the Melville Bugt Trough (MBT) to the northwest of Disko Bugt has only recently been mapped and shows that ice reached the shelf edge at the LGM, making it ~80 km more advanced than previously thought (Newton et al., 2017). If the MBT was fully-occupied by an ice stream at the LGM, as suggested by seafloor landforms, it would have drained an area of the GrIS at least three times larger than Jakobshavn Isbræ (which currently drains ~7% of the GrIS), highlighting the need for a better understanding of its post-LGM evolution. This project aims to unravel the mechanisms and processes that drove ice sheet retreat in the past, and whether these processes were linear and steady or non-linear and catastrophic, through the analysis of sediments in MBT. The proximity of the study area to the recently identified meteor impact site in northwest Greenland means that complimentary evidence may also be preserved in the offshore sedimentary record (e.g. shocked quartz) and may help unravel the causes of the Younger Dryas.
Analysis of lithological changes and the evolution of foraminifera assemblages will provide insights into the evolution of the West Greenland Current and its relationship with ice sheet dynamics in the region. To address these ideas six shallow sediment cores, retrieved from the study area in Melville Bugt, will be analysed using a range of sedimentological, palaeontological, geochemical, and statistical techniques. The results of these analyses will offer the opportunity to reconstruct palaeoceanography and environmental changes in this area of Greenland to develop a more complete picture of ice sheet evolution in the past and the potential implications this has for future scenarios under a warming climate.