The coastal migration theory: Formulation and testable hypotheses

Abstract

The presence of well-documented sites in the Americas predating and south of the opening of an ice-free corridor in the North American ice sheets lends credence to a Pacific coastal migration theory (CMT) explaining the route for the initial peopling of the Americas. This theory has been informally discussed for more than 50 years, but until recently, has been largely ignored and never properly defined as a result. We provide a formal definition of the CMT which, briefly stated, is that Upper Paleolithic populations moved from Asia to coastal regions along the northwestern Pacific Rim between ∼45–30 ka. By ∼30 ka these coastal populations developed a mixed maritime, nearshore, and terrestrial adaptation involving the use of boats, shell fishhooks for deep-water fishing, and a stemmed point and macroblade core technology. About 25–24 ka a subset of these coastal populations became isolated somewhere in the vicinity of the Japan/Paleo-Hokkaido, Sahkalin, Kuril (PSHK) region, developing genetically into the ancient Native American (ANA) populations that eventually settled the Americas. Between ∼22–16 ka these ANA people began migrating by foot and boat along the southern Beringian coast and down the Alaskan and Canadian coastline into the Americas south of the continental ice sheets before eventually expanding inland. We develop a series of testable hypotheses through which the CMT can be examined.