The Guaraní expansion through the Lowlands of South America

This study examines the expansion of Amazonian forager-horticulturalists grouped within the Guaraní archaeological unit, who migrated from southwestern Amazonia to southeastern South America, spanning much of the La Plata basin and the Atlantic coastal slope of southeastern Brazil, covering over 2500 km in a relatively short period. This process, marked by rapid expansion and extensive territorial coverage, represents one of the most remarkable migrations recorded among known pre-industrial societies. The initial expansion probably began in southwestern Amazonia, progressing southeastward to the headwaters of the La Plata basin, where this population appears as a weak archaeological signal around 500 CE. Approximately 800 years later, these Amazonian groups reached the Río de la Plata estuary, 1400 km farther south. Based on calibrated age ranges, the spatial distribution of Guaraní sites across the basin, and the application of various statistical methods (Silhouette Coefficient Analysis, Hierarchical Cluster Analysis, Principal Components Analysis, and Summed Probability Distribution of radiocarbon ages), this expansion was divided into four clusters or phases, reflecting a complex migratory process. In addition to redefining the dynamics of Guaraní expansion, this study provides a better alignment with linguistic dispersion models of these populations and offers new perspectives on how canoeing societies, in general, can rapidly spread across a vast territory within a brief archaeological timeframe.