Thanks to new high-resolution surveys of the seafloor, scientists think they have evidence of the subduction process starting in the Atlantic Ocean off the coast of Portugal. If they are right, this nascent subduction zone could close the Atlantic Ocean — in roughly 200 million years.

Buried more than a kilometer beneath the East Antarctica Ice sheet, the Gamburstev Subglacial Mountains have proven to be a geological puzzle for more than 5 decades. How did these mountains form? When did they form? And what makes this ancient mountain range one of the least-understood tectonic features on Earth?