Characterising the ice-water-bedrock interface of Ellsworth Subglacial Highlands, West Antarctica

Antarctica is the largest mass of ice on Earth and is losing ice at increasing rates. This has direct consequences for society in many ways, such as sea level rise or changes in ocean circulation. The international scientific community is focusing on understanding the present and past ice flow dynamics in order to reduce the uncertainties on the sea level rise projections. Subglacial conditions are a fundamental part to understand the ice flow dynamics. In particular, the role of subglacial hydrology is critical to the behaviour of the ice because it can enhance ice flow downstream by lubricating the ice-bed interface. Despite the importance of the subglacial hydrological system ice dynamics, there is a lack of detailed subglacial-water characterisation in West Antarctica. In addition, subglacial topography also plays a key role in ice dynamics, and therefore a thorough understanding of it is of great interest to the scientific community. In this thesis, I present new findings of subglacial hydrology in the Ellsworth Subglacial Highlands, located in the interior of West Antarctica, and characterise the evolution of the hydrological system over the last 150 kyr. Additionally, I update the subglacial topography using unpublished RES data and describe new topographical features that affect both the subglacial hydrological system and the ice flow dynamics. Moreover, an exhaustive description and analysis of internal reflection horizons are also provided in order to elucidate past ice flow dynamics and to better understand the influence of subglacial hydrology on the ice flow dynamics. Lastly, I present the potential implication of the results of this thesis on the current Subglacial Lake CECs exploration program. Integration of these new findings in ice sheet models will improve our understanding of the evolution of the West Antarctic Ice Sheet, and its sensitivity to the subglacial hydrological system