Poseidon Ocean

The Poseidon Ocean is a supposed ocean that existed in the Mesoproterozoic period of the geologic timescale (between 1600 and 1000 million years ago). It began to form when a hotspot collided with lithosphere that was already in an extensional regime that allowed rifting to occur at the onset of hotspot volcanism that created the Mackenzie Large Igneous Province. This hotspot, known as the Mackenzie hotspot, produced passive rifting to form a triple junction. As two of the rift arms continued to grow, they created the Poseidon Ocean basin. The third rift arm failed to open fully, creating an aulacogen.