Flavours of Allan Hills, Antarctica Ice Cores: Characterizing the Stable Water Isotope Record from a Theoretical Perspective

Abstract

Stable water isotope measurements from polar ice cores are used as a paleothermometer, providing high-resolution information about past precipitation as a function of climate. Traditionally, ice cores’ paleoclimate records have been obtained from high accumulation ice divides, where the assessment of climate signals and effects of glacial deformation is easily understood. Sites with complex stratigraphy offer snap- shots of ice that are older, albeit the detangling of the climate signal is further complicated. The Allan Hills blue ice area has been a site of interest for discovering the oldest ice on Earth, with the most recent work by COLDEX discovering 6-million-year-old ice. However, the meteorological and glacial origins of Allan Hills ice are not well understood, hindering our ability to truly parse the climate record from the water isotope record. Here, I build on earlier work by Davidge (2025) to create a new database of water isotope measurements generated by COLDEX, establish a local meteoric water line for the Allan Hills area, and suggest at least two separate origins of ice flow into the region. This thesis establishes a framework for interpreting the Allan Hills water isotope record from a theoretical perspective.