Quaternary; Landslide; Geomorphology; Relative dating; Glacier foreland; Glacial lake; Patagonian Ice Sheet; Paleogeography; South America

We report some of the world's largest terrestrial landslides in the eastern piedmont of the Patagonian Ice Sheet (PIS) along the traces of the former Lago Buenos Aires and Lago Puyerred on glacier lobes and lakes. More than 283 large rotational slides and lateral spreads followed by debris slides, earthflows, rotational and translational rockslides, complex slides and few large rock avalanches detached some 164 ± 56km3 of material from the slopes of volcanic mesetas, lake-bounding moraines, and river gorge walls. Many of these landslide deposits intersect with well-dated moraine ridges or former glacial-lake shorelines, and offer opportunities for relative dating of slope failure.We estimate that >60% of the landslide volume (~96 km3) detached after the Last Glacial Maximum (LGM). Giant slope failures crosscutting shorelines of a large Late Glacial to Early Holocene lake (“glacial lake PIS”) likely occurred during successive lake-level drop between ~11.5 and 8 ka, and some of them are the largest hitherto documented landslides in moraines.