Glaciers in the Rofental, Ötztal Alps, Austria: a sedimentological perspective

Glacial environments are undergoing rapid transformations due to climate change, which can be observed in the sedimentological processes associated with ice masses. In mountain regions, these can vary within a catchment due to controlling factors such as geological setting and debris sources, slope processes and instability, orientation of the glacier, and glacial dynamics. The Rofental is a valley in the Austrian Alps with a rich history in glaciological research, and hosts several glaciers that exemplify some of these differences. However, until now, there has been no detailed sedimentological work done, in spite of the yearly increase in supraglacial debris on many glaciers, as well as significant ice margin and forefield changes. To address this, we present the results of sedimentological and geomorphological mapping from 2023 and 2024, integrating ground-level observations and drone imagery from fieldwork at 3 different glaciers in the Rofental area: the Hintereisferner, Guslarferner, and Vernagtferner. These glaciers have varying degrees of debris cover and, in some cases, exhibit preservation of delicate sedimentary depositional features on the ice itself. Questions arise regarding transport mechanisms of the debris, including the relative influence of englacial meltout, supraglacial stream deposition and mass wasting (e.g. rockfalls and debris flows). The origins of this debris, its impact on preservation of dead ice over the coming years, and its influence on downwasting rates deserve investigation. By studying these glaciers, we can gain insights into how they will continue to evolve over time, compare them to the previous sedimentary record, and potentially revise some of the established characteristics for retreating glaciers.