Where to find 1.5 million yr old ice for the IPICS "Oldest-Ice" ice core

Abstract

Abstract. The recovery of a 1.5 million yr long ice core from Antarctica represents a keystone of our understanding of Quaternary climate, the progression of glaciation over this time period and the role of greenhouse gas cycles in this progression. Here we tackle the question of where such ice may still be found in the Antarctic ice sheet. We can show that such old ice is most likely to exist in the plateau area of the East Antarctic ice sheet (EAIS) without stratigraphic disturbance and should be able to be recovered after careful presite selection studies. Based on a simple ice and heat flow model and glaciological observations, we conclude that positions in the vicinity of major domes and saddle position on the East Antarctic Plateau will most likely have such old ice in store and represent the best study areas for dedicated reconnaissance studies in the near future. In contrast to previous ice core drill site selections, however, we strongly suggest significantly reduced ice thickness to avoid bottom melting. For example for the geothermal heat flux and accumulation conditions at Dome C, an ice thickness lower than but close to about 2500 m would be required to find 1.5 Myr old ice (i.e., more than 700 m less than at the current EPICA Dome C drill site). Within this constraint, the resolution of an Oldest-Ice record and the distance of such old ice to the bedrock should be maximized to avoid ice flow disturbances, Published by Copernicus Publications on behalf of the European Geosciences Union. H. Fischer et al.:Where to find 1.5 million yr old ice for the IPICS "Oldest-Ice" ice core for example, by finding locations with minimum geothermal heat flux. As the geothermal heat flux is largely unknown for the EAIS, this parameter has to be carefully determined beforehand. In addition, detailed bedrock topography and ice flow history has to be reconstructed for candidates of an Oldest-Ice ice coring site. Finally, we argue strongly for rapid access drilling before any full, deep ice coring activity commences to bring datable samples to the surface and to allow an age check of the oldest ice.

Spatial and temporal distributions of surface mass balance between Concordia and Vostok stations, Antarctica, from combined radar and ice core data: first results and detailed error analysis

“…Surface mass balance maps thus constitute a major input for selecting the coring site (e.g. Fischer et al, 2013). However, despite the large possibilities of the proposed method for providing large-scale accumulation fields, a comprehensive and high-resolution coverage of the entire Antarctic ice sheet is not realistic.…”

Ice-flow reorganization within the East Antarctic Ice Sheet deep interior

“…Identifying regions of former fast flow in the South Pole region has implications for a variety of ongoing investigations, including interpretation of ice-core climate records (Casey et al 2014), the search for recoverable million year old ice (e.g. Fischer et al 2013;van Liefferinge & Pattyn 2013) and possible expansion of the IceCube neutrino detector (Aartsen et al 2014).…”

Seismic wave propagation in anisotropic ice – Part 1: Elasticity tensor and derived quantities from ice-core properties

“…This distinction is important as conductivityinduced layers are isochrones; by following conductivityinduced reflections in radar data, layers of equal age can be followed over large distances. Currently, identifying and tracing undisturbed layering is one of the main methods being used to identify the location of a site for a potentially 1.5 My old ice core in East Antarctica (Fischer et al, 2013).…”