In the Early Triassic period, Pangea gradually began to break apart into two major continents again, the result of a seafloor-spreading rift. (This rift was similar to today’s Mid-Ocean Ridge in the Atlantic Ocean, a volcanic seam that continues to spread, and along which the volcanic island of Iceland was born.) The Triassic rift extended westward from the Tethys Sea across what is today the Mediterranean Sea. The action of this rift separated northern Laurasia from southern Gondwanaland, which would eventually lead to the opening of the proto-Atlantic (or early Atlantic) Ocean. As North Africa split from southern Europe, there was a gradual rise in sea level that flooded south and central Europe.

Towards the Middle and Late Triassic periods, the spreading rift between North Africa and Europe grew westward, and it began to separate North Africa from the eastern part of North America. The resulting rift valley was the first true stage in the formation of the proto-Atlantic Ocean.