In ancient boulders, new clues about the story of human migration to the Americas

A geological study provides compelling evidence to support the hypothesis that ancient humans migrated into the Americas via a coastal route. By analyzing boulders and bedrock, a team shows that part of a coastal migration route became accessible to humans 17,000 years ago. During this period, ancient glaciers receded, exposing islands of southern Alaska’s Alexander Archipelago to air and sun — and, possibly, to human migration.