Ross Ice Shelf Geothermal Flux (RISGF) - Direct Borehole Measurements as Part of the New Zealand Ross Ice Shelf Programme

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

The geothermal flux is a significant source of heat in polar subglacial environments. It affects the temperature at the base of ice sheets, influencing the distribution and rate of basal melting or freezing. These processes affect ice-sheet mass balance because basal melting facilitates fast sliding of ice. The geothermal flux is used in ice-sheet models that predict the contribution of the West Antarctic Ice Sheet to global sea-level rise. Yet, despite the importance of the geothermal flux, there are relatively few direct measurements, mainly because it is so difficult to access sub-ice environments. This project aims to obtain new constraints on the magnitude and spatial distribution of geothermal flux beneath the Ross Ice Shelf through collaboration with a New Zealand research project that is planning to drill through the ice shelf. Due to the paucity of observations, the geothermal flux distribution used in ice-sheet models typically falls within a relatively narrow range and is represented at low spatial resolution, based on geological or remotely-sensed properties of the underlying lithosphere. However, these models of Antarctic geothermal flux distribution do not appear to be consistent with each other in both magnitude and distribution, suggesting that spatial patterns of geothermal flux below the West Antarctic Ice Sheet are underconstrained. Using data collecting from a down-borehole geothermal probe, the team will test the hypothesis that the central part of the West Antarctic rift system is characterized by lower geothermal flux values than the previously sampled southern rift shoulder. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.