WHEN SOUTH AMERICA WAS COLONIZED: AN AQUATIC MODEL FOR HUMAN PEOPLING BY PLEISTOCENE/HOLOCENE TIMES

South America is a maritime hemi-continent surrounding by Pacific and Atlantic Oceans and Caribbean Sea. During Pleistocene-Holocene transition the climatic and environmental conditions were wavy, accompanied by changes in sea levels, and cooling episodes such us Younger Dryas. In these terms, has been a critical time for the dispersal of human societies around all over Southern Cone extension. A brief review of the evidences for a late Glacial cooling episode and the arguments used to suggest or reject the existence of a Younger Dryas is presented. In fact, people looking for places to settle, even temporarily, had to accept high environmental variability and probably it became harsher climatic conditions between 11—10 Ka BP. The changes of continental and maritime characteristics of South America for the beginning of colonizing process, the palaeoenvironmental implications, and archaeological evidence are discuss.