Late Pleistocene glaciation in South America

Records of Late Pleistocene glaciation show how glaciers responded to climate change during the last glacial cycle (∼129.0–11.7 ka). Such records rely on detailed geomorphic and geochronological analysis over a wide spatial and temporal scale and have benefitted greatly from advances in techniques in recent years. This review looks at current understanding of glacial activity during the Late Pleistocene across the Andean Cordillera in South America, from 11ºN in the Northern Andes to 55ºS in the Southern Andes. The focus is mostly on the terrestrial glacial landform record, and particularly constraints on the timing of glacial advance and retreat. In this respect, the proliferation of cosmogenic nuclide exposure dating over the last two decades has transformed the picture of glacial geochronology in South America. There is now abundant evidence of glacial activity prior to the onset of the global Last Glacial Maximum at ∼26.5 ka, with many glaciers much more extensive during this time. The imprint of the global Last Glacial Maximum is also clear across the Andean Cordillera, followed by general retreat between∼19.0 ka and∼14.6 ka during the Heinrich Stadial-1 period, with evidence for stillstands or readvances in some places. Prior to the Holocene, many glaciers stabilized or advanced during the Antarctic Cold Reversal period (∼14.6–12.9 ka), with some evidence for glacial advance during the Younger Dryas Stadial Stadial as well (∼12.9–11.7 ka). Many spatial gaps remain in the record of South American glaciation and age uncertainties also present a challenge to ascribing particular glacier limits to millennial-scale climate events. The review highlights the advances that have been made in recent years and where future investigation into Late Pleistocene glaciation in South America may be particularly useful.