Research project IM/RT/23/FROID (Research action IM)
One of the most intriguing mysteries in our understanding of the Quaternary (i.e., last 2.7 million years) relates to the Mid-Pleistocene transition (MPT), around 1,200,000 to 800,000 years, during which glacial cycles become longer and stronger. To date, the forcing and responses of the climate system components that led to this enigmatic transition remain largely unknown. Greenhouse gases that directly affect the Earth’s radiative balance are believed to have played an important role during the MPT but indirect indicators of their evolution remain ambigous and uncertain. The analysis of air trapped in ice cores provides direct access to past changes in greenhouse gas concentrations, but the oldest continuous records only spans over the last 800,000 years. To obtain older ice, several international teams are currently preparing and undertaking deep-drilling efforts (i.e., several kilometers) on the Antarctic ice sheet. An alternative and somewhat 'out of the box' approach is to collect old ice at and near the surface in blue ice areas (BIAs). These BIAs form where the bedrock geometry redirects (old) englacial ice towards the ice sheet's surface, with katabatic winds removing snow and younger ice. Therefore, in BIAs, old ice can directly be sampled from the surface or by coring at a relatively shallow depth, allowing to collect large quantities of ice. In this project, we will make use of the exceptional setting of the Princess Elisabeth (PE) Station which is in direct vicinity of many BIAs. We will study the local ice stratigraphy by combining fieldwork, numerical modelling, and laboratory analysis of collected samples (including absolute dating). This will eventually culminate in identifying a prime site for very old ice to be contained, where a drilling of up to a few hundred meters will be performed with the goal to collect some of the oldest ice on Earth.
