Recent ice-contact delta formation in front of Pio XI glacier controls sedimentary processes in Eyre Fjord, Patagonia

Abstract

Pio XI Glacier (49°S) is the largest and one of the very few advancing glaciers in Patagonia. Satellite data indicate that the main glacier terminus transitioned from calving to land-based around 2010, effectively resulting in the formation of an ice-contact delta at the head of Eyre Fjord. Here, we investigate how this ice-contact delta formation affected sediment transport processes in Eyre Fjord. Sediment cores and seismic profiles collected along the fjord provide evidence for a relatively abrupt increase in the number and magnitude of turbidity currents, coeval with the formation of the ice-contact delta. This observation is supported by modern summer hydrographic observations and bathymetric data. We posit that the ice-contact delta formation resulted in sediment input being concentrated at specific subaerial locations across the fjord head, which favoured the development of plume-triggered turbidity currents. This suggests that a sudden increase in turbidite thickness in fjord sediment records could represent ice-contact delta development at fjord heads.