The reconstruction of the British-Irish Ice Sheet (BIIS) dynamics from deep-water sediments on the NW Irish continental margin: The reconstruction of the British-Irish Ice Sheet (BIIS) dynamics from deep-water sediments on the NW Irish continental margin

The British-Irish Ice Sheet (BIIS) was a partially marine-based, dynamic ice-sheet that during its last extension in the Late Quaternary followed sub- milankovitch climatic oscillations. In deep-water these advance and retreat events are displayed by changes in the sedimentation styles. Presence of Ice Rafted Debris (IRD) and mass transport deposits such as turbidites are typical of cold intervals, whereas hemipelagites and contourites are deposited during warm periods.
Three different depositional systems are part of this research, the Rockall Trough, the Donegal-Barra fan and three channels on the Irish continental shelf.
Lithofacies based on sedimentological identification, physical properties and X-rays, together with abundance of Neogloboquadrina pachyderma left coiling and IRD concentration are the methodologies used. Isotopic analysis is being carried out on core CE10008-20A from the Rockall Trough for reconstruction of paleotemperature and paleoproductivity. Grain size analysis is being used to reconstruct paleocurrents and quantify their speed. Two radiocarbon dates, in collaboration with the BRITICE-Chrono consortium, allow the addition of a preliminary chronostratigraphy.

The results obtained will allow the correlation of the three different environments and will be used to reconstruct and chronologically constrain the variability of the BIIS in this specific deep-water sector. Particular interest will be focused on grain size analysis and the possible role of the BIIS in the North Atlantic Oceanic Circulation.