Plio-Pleistocene glacial history of the Melville Bugt Ice Stream

In this work we use high-resolution seismic reflection surveys collected across the northeast Baffin Bay region to investigate the glacigenic Melville Bugt Trough Mouth Fan (MB-TMF). The MB-TMF stratigraphy is characterised by over 100 km of progradation since ~2.7 Ma and the heterogeneous truncation or subsidence of topset strata. Variation in topset character is thought to relate to the waxing and waning of the northwest sector of the Greenland Ice Sheet across the shelf since ~2.7 Ma. 3D seismic reflection data reveal the preservation of multiple sets of mega-scale glacial lineations, suggesting that grounded ice extended across the shelf a number of times since the onset of the Middle Pleistocene Transition. Seismic geomorphology and facies analysis of the prograding clinoforms show repeated observations of debrites and gully systems. These features, when considered with other evidence of adjacent glacial landforms and strata, are taken to infer gravity-driven processes and the presence of meltwater-related hyperpycnal flows in areas proximal to the ice sheet on the outer shelf. Bottomset contourites at the base of the continental slope also provide insights into the evolution of the West Greenland Current in Baffin Bay through the Pleistocene, with deposition estimated to have started in the latest Calabrian, based on the current age model. Regional stratigraphic mapping shows that the MB-TMF can be summarised into four stages that were primarily controlled by variations in ice sheet erosion patterns, topographic forcing of ice flow, and changes in accommodation that are related to glacigenic deposition and tectonic subsidence.