A new study looking at nitrogen isotopes from ocean floor sediments shows that the Bering Land Bridge, the strip of land that once connected Asia to current day Alaska and allowed people to migrate to North America, emerged more recently than previously thought. Scientists had thought the Bering Land Bridge emerged around 70,000 years ago. But the new evidence suggests that the bridge appeared only 35,700 years ago, still during the last ice age but not quite as long ago. The finding adds clues to our understanding of human migration patterns. The researchers say the timing of human migration into North America from Asia remains unresolved, but genetic studies tell us that ancestral Native American populations diverged from Asian populations about 36,000 years ago, the same time that researchers found the Bering Land Bridge emerged. 

"As it turns out, our research into sediments from the bottom of the Arctic Ocean told us not only about past climate change but also one of the great migrations in human history," said Princeton's Jesse Farmer, a postdoctoral researcher and co-lead author on the study.