Long-lasting impacts of a 20th century glacial lake outburst flood on a Patagonian fjord-river system (Pascua River)

Glacial Lake Outburst Floods (GLOFs) are an increasing threat to Patagonian environments and communities. Here, we investigate the geomorphological hydrological impacts of a historical GLOF from Chile's third largest river (Pascua River), which discharges at head Baker Fjord (48°S). To do so, maps satellite imagery past century recent bathymetric data were examined, 1.4 m long sediment core taken ~4 km offshore Pascua River mouth was analyzed. Geomorphological suggest that two main subaerial channels fjord-head delta extend subaqueously as submarine channels. The on flank channel evaluate changes in activity through time. Results show sediments composed distinct units separated by 6-cm thick sandy turbidite dated 1945?10+8 CE. Historical evidence suggests event deposit corresponds ~ 256 × 106 m3 proglacial lake Lucía Glacier (Bergues Lake) discharged into River. Before CE, sedimentation coring site consisted coarse silt fine sand, likely representing deposition turbidity currents. After very silts clays, settling surficial plume. This switch timing abandonment eastern distributary represents reorganization hydrology fjord-river system caused CE GLOF. study provides first report northeastern part Southern Icefield, it demonstrates GLOFs can have long-lasting downstream systems.