Archaeologists have conducted a study of lithic material from the Pilauco and Los Notros sites in north-western Patagonia, revealing evidence of human occupation in the region prior to the Younger Dryas period.The Younger Dryas, which occurred circa 12,900 to 11,700 years BP), was a cooling event which marked a return to glacial conditions, temporarily reversing the climatic warming of the preceding Late Glacial Interstadial.The period in which humans arrived in South America, in particular, north-western Patagonia, has been the subject of an ongoing debate by academics for many years.Previous archaeological evidence and palaeogenetic studies have suggested human presence between 16...