Shifting plates and a mantle plume carved the Atlantic’s 500-km canyon
Geoscientists mapped the King’s Trough, a 500-kilometer canyon-like feature about 1,000 km off Portugal, and concluded it formed around 37–24 million years ago due to a transient plate boundary that fractured the seafloor. A hot mantle plume likely weakened the crust, aiding tectonic forces; the boundary later migrated south toward the Azores, with the finding supported by high-resolution mapping and volcanic rock analysis and suggesting parallels with the Terceira Rift.