Studying preserved footprints in New Mexico continues to provide insight into the first human movements in North America ... 23,000-year-old date, showing that humans were on the continent ...

Seismic mapping of North America has revealed that an ancient slab of crust buried beneath the Midwest is causing the crust above it to "drip" and suck down rocks from across the continent.

The slab's pull has created giant "drips" that hang from the underside of the continent down to ... a wider project led by Hua to map what lies beneath North America using a high-resolution ...