From Asia to the Americas by boat? Paleogeography, paleoecology, and stemmed points of the northwest Pacific

Rising postglacial seas have flooded the world's continental shelves, limiting our ability to reconstruct human migrations, the history of settlement along Pleistocene coastlines, and the antiquity of coastal shell middens. This includes the southern coast of Beringia, where dramatic landscape changes make it difficult to test the coastal migration theory, which proposes that Upper Paleolithic peoples followed Pacific shorelines from northeast Asia to the Americas. To help overcome such problems, this paper discusses the paleogeography and paleoecology of Late Pleistocene North Pacific coastlines, then examines Pacific Rim technologies for possible evidence of a coastal migration. By ∼16,000 ± 1000 cal BP, the Pacific Rim was a plausible migration route, entirely at sea level, with rich and diverse resources from both marine and terrestrial ecosystems. Within this vast region, scattered Late Pleistocene technological assemblages that include leaf-shaped bifaces and stemmed projectile points found in coastal or peri-coastal sites from Japan and Kamchatka to western North America, and much of South America may support the idea that a coastal migration contributed to the peopling of the Americas.