Characterizing the American Upper Paleolithic.

In North America, there are enough sites with relatively large tool assemblages predating ~13,500 calibrated years before the present (cal yr B.P.) to allow assessment of the underlying characteristics of their shared lithic tradition. Their shared technological features involve the use of dual core-and-blade and biface technologies similar to those in the Northeast Asian Late Upper Paleolithic. These dual approaches were often merged to produce small projectile points, including stemmed point forms using an elliptical cross-sectional ogive design. Similar dual lithic technologies are found in assemblages in northern Japan dating to ~20,000 cal yr B.P. We suggest a group with a similar lithic technology became isolated somewhere in the vicinity of the Paleo-Sakhalin-Hokkaido-Kuril region, developing genetically into ancestral American populations. Between ~22,000 and ~18,000 cal yr B.P., a subset of this population migrated along the southern Beringian and Northwest coasts into the Americas. By ~16,000 to ~15,000 cal yr B.P., they had become widely dispersed across North America.