Paleoenvironmental Reconstructions at a Megamammal Hunting Site in the Late Pleistocene of the Pampas (Argentina)

Megafauna in South America became extinct by the end of the Late Pleistocene and the relative role of human influence, climate, and other indirect factors in driving these population declines is still a matter of debate. The Campo Laborde archeological site (Pampas, Argentina) offers an exceptional opportunity to understand the complex interactions between climate, ecosystems, and human populations during that time. This study integrates biological proxies (pollen, diatoms, chrysophytes, silicophytoliths) within a stratigraphic framework (sedimentological and geochemical analyses) to reconstruct the paleoenvironmental conditions that prevailed before, during, and after the megamammal hunting and processing event. The results indicate a gradual environmental shift from a stable aquatic environment characterised by greater water availability to a more unstable, shallow and periodically desiccated aquatic environment. Particularly, during the human occupation of the site (∼12,600 cal years BP), the shallow and flooded areas acted as attractive zones due to the availability of vital resources such as water, vegetation, and fauna. This environmental evolution was primarily driven by local factors (e.g. topographic setting and hydrological dynamics) and secondarily by regional processes (seasonal precipitation). These results emphasise the importance of paleoecological studies to reconstruct detailed environmental histories at both local and regional scales.