We are using a novel method to date grounding-line retreat that utilises glaciological measurements of the time of the last disturbance of ice rises – regions of slow-moving grounded ice, adjacent to fast-moving floating ice – as the grounding line retreated past them.During two field seasons (Figure 1) we used a unique BAS ice-penetrating radar to measure the internal deformation of these ice rises in unprecedented detail.We are now combining these data with radar observations of structures that form within the ice rises due to the peculiar way in which ice deforms in these locations.This will allow us to constrain when these features formed and when the grounding line retreated past them.We are hereby presenting a new dating method based on inverse techniques, which aims at calculating consistent gas and ice chronologies for several ice cores.
Another useful technique is to identify events which are seen in other types of climate records, such as historical, tree ring and sedimentary records.
This method enables us to gather widespread chronological information and to use regional or global markers (i.e., methane, volcanic sulfate, Beryllium-10, tephra layers, etc.) to link the core chronologies stratigraphically.
Confidence intervals of the new dating scenarios can be calculated thanks to the probabilistic formulation of the new method, which takes into account both modeling and data uncertainties.
From: Wikimedia Commons We can indirectly date glacial sediments by looking at the organic materials above and below glacial sediments. Marine geological constraints for the grounding-line position of the Antarctic Ice Sheet on the southern Weddell Sea shelf at the Last Glacial Maximum.
Radiocarbon dating provides the age of organic remains that overly glacial sediments.