The debate has raged in the world of paleo-climate research for years: When did the land bridge that once connected Asia and North America flood?
Some researchers say the presence of Pacific species in the Arctic makes the case for some 13,000 years ago. Others, however, point to sediment cores collected from the area as evidence that the flooding occurred later, about 11,500 years ago.
For Tamara Pico, the issue is not which date is right, but how both — taken together — paint a fuller picture of how sea levels changed in the strait over more than 1,500 years.
Based on that picture, Pico, Ph.D. ’19, was able to deduce how the ice sheets that covered North America responded to the warming climate, and how their melting might have contributed to climate changes. The study is described in a Feb. 26 paper in Science Advances.
“If we can understand sea-level change in the region around the ice sheet, we can infer the past history of the ice sheet,” said Pico, who worked in the lab of Jerry Mitrovica, Frank B. Baird Jr. Professor of Science, as a graduate student and is now a National Science Foundation postdoctoral scholar at Caltech. “For me, the central question of this study is about understanding when and how much ice melted [during the deglaciation], because if you don’t know how much ice volume melted, then you don’t know how ice sheets are responding to a changing climate, and that’s really the fundamental question.”
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