It's still open to scrutinizing and still controversial but, ongoing digs are bringing in new evidence showing ancients came to South America as early as fifteen thousand B.C. via the South Pacific, most probably via the very boats or rather rafts Thor Hydradahl used in the Kon Tiki, Reed rafts.
You probably wont be able to get any real information for a while on these digs until they all approve of them. Check with National Geographic.