Mapping age and basal conditions of ice in the Dome Fuji region, Antarctica, by combining radar internal layer stratigraphy and flow modeling

Abstract. The Dome Fuji (DF) region in Antarctica is a potential site for an ice core with a record of over one million years. Here, we combine the internal airborne radar stratigraphy with a 1-D model to estimate the age of basal ice in the DF region. The radar data used in the study were collected in a survey during the 2016–2017 Antarctica season. We transfer the newest age–depth scales from the DF ice core to isochrones in the surrounding 500 km × 550 km region through traced radar isochrones. At each point of the survey the 1-D model uses the ages of isochrones to construct the age–depth scale at depths where dated isochrones do not exist, the basal thermal conditions, including the thickness of a potentially present basal layer and surface accumulation rates. Our resulting age distribution and age density suggest that a few promising sites with ice older than 1.5 million years in the DF region might exist. The deduced melt rates and presence of stagnant ice map provides more constraints for finding sites with a cold base. The accumulation rates range from 0.015 to 0.038 m a-1 ice equivalent. The numbers of picked isochrones and the timescale of the ice core severely affect the model results according to sensitivity studies. Our study demonstrates it is possible to find the old ice in the DF region, the constraint from deep radar isochrones and a trustworthy timescale could improve the model estimation.