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JR244 - Primary region of interest. Three Workpackages : Palaeo -Ice Sheets (Ice Sheets) Quaternary Sediments (CPC) Evolutionary History (ECE). Palaeo-Ice Sheets swath bathymetry target areas. Quaternary Sediments coring target areas.
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JR244 - Primary region of interest Three Workpackages: Palaeo-Ice Sheets (Ice Sheets) Quaternary Sediments (CPC) Evolutionary History (ECE)
Modelled ice sheet at Last Glacial Maximum in southern Weddell Sea Bentley et al., Geology (2010) Note that model predicts elongate ice shelves (blue) over cross-shelf bathymetric troughs, but these are unconstrained by marine data. Therefore marine data are important for both understanding ice sheet history and evolutionary history & community development of benthic biota.
Weddell Sea is world largest ocean bottom water factory, and therefore an important driver of ocean circulation Rahmstorf, Nature (2002) Ice shelves are important in the modern process of bottom water production in the Weddell Sea. If they were not present during glacial maxima then this has important implications for how bottom water was formed, and wider implications for ocean circulation as a whole.
New equipment – gravity corer To be delivered and installed on the JCR during refit, and trialled en route from Frederikshavn to Portsmouth. This will be the be the most important sampling system for the Palaeo-Ice Sheets and Quaternary Sediments WPs. Photo shows a piston coring system on RV Pelagia, but the overall design of the new gravity coring system is quite similar
External equipment - high-resolution seismic reflection profiling Seismic reflection equipment will be provided by Palaeo-Ice Sheets collaborators from University of Hamburg (LOU agreed). It is required for investigations of the role of substrate (the nature of the continental shelf materials overridden by ice) in past glacial dynamics. Image above is an example from the Amundsen Sea revealing a close correspondence between substrate type and sea-floor morphology.
Main uncertainty – sea ice Above image shows sea ice distribution around Antarctica on 15th February this year. There was open water over the Filchner Trough, but our other target areas were inaccessible. If information on sea ice distribution in target areas is unfavourable at the start of the cruise, then contingency work will be carried out in South Orkney region before continuing to the southern Weddell Sea