3-D thermal structure and age modelling of the ice sheet in the Dome Fuji region, Antarctica

The acquisition of 1.5 Myr ice cores is a major objective of Antarctic exploration, aiming to enhance our understanding of the causes behind the Mid-Pleistocene Transition. Here, we combine radar observations and ice-flow modeling to investigate the age, basal thermal state and temperature of the ice sheet in the Dome Fuji region, Antarctica, to provide significant information for selecting the drill site.

We use a 3-D ice-flow model to couple the mechanical, thermal and hydrological processes in the ice sheet. Radar internal stratigraphy and the previously identified subglacial waterbodies are incorporated as constraints in the inverse modelling to improve the reliability of the model results. The modelled basal temperature reaches the pressure melting point in most of the study area, while there is a lower modelled basal temperature near the New Dome Fuji (NDF, 77.789° S, 39.053° E) and southeast of the old Dome Fuji drill site (DF, 77.317° S，39.703° E). The relative basal reflectivity, derived from radar bed return power and modelled 3-D ice temperature, is relatively low in these areas as well. This suggests a lower possibility of basal melting, and thus suggests that a longer climate record might be preserved in the ice. The modelled age of of the ice near the base reaches 1.5 Myr near NDF and south of DF. These modelled results enhance the understanding of ice dynamics, age distribution and thermal structure in the Dome Fuji region.