Unravelling Antarctic sediment processes by U-Series dating

The West Antarctic Ice Sheet (WAIS) is a major source of uncertainty in predicting future sea level rise. Because its base lies below sea level, it is particularly sensitive to warming from both the ocean and atmosphere. If destabilized, it contains enough ice to raise global sea levels by about 3.3 meters. One of the biggest challenges in forecasting its future lies in our limited understanding of what happens beneath the iceespecially the poorly known subglacial water systems and how sediments are eroded, stored, transported, and deposited both today and throughout past glacial-interglacial cycles. This project aims to fill that knowledge gap by applying a relatively new dating method, called uranium-series comminution dating, to fine sediments collected near major Antarctic ice streams and from deep-sea cores spanning the last 400,000 years. This technique acts as a geological clock, beginning when a rock is ground down by glacial activity into very fine grains (smaller than 50 micrometers). By measuring changes in uranium isotopes, the project will estimate how long these sediments remained beneath the ice before being transported and deposited offshore. This provides valuable insights into past patterns of subglacial erosion and sediment movement, which can help constrain ice sheet models used to predict future changes. Although still in development and rarely applied in polar regions, this technique holds great promise for improving our understanding of ice sheet dynamics and reducing uncertainties about the WAISs potential impact on future sea level rise.