What is the name of the vast global ocean that surrounded the supercontinent during the late Paleozoic and early Mesozoic years?

Panthalassa, also known as the Panthalassic or Panthalassan Ocean, was the superocean that surrounded the supercontinent Pangaea. During the Paleozoic - Mesozoic transition c. 250 Ma it occupied almost 70% of Earth's surface. Its ocean-floor has completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific ("old Pacific") or Proto-Pacific because the Pacific Ocean developed from its centre in the Mesozoic to the present.

Prior to the breakup of Pangea, one enormous ocean, Panthalassa, existed on Earth. Currents in this ocean would have been simple and slow, and Earth’s climate was, in all likelihood, warmer than today. The Tethys seaway formed as Pangea broke into Gondwana and Laurasia. In the narrow ocean basins of the central North Atlantic, restricted ocean circulation favoured deposition of evaporites (halite, gypsum, anhydrite, and other less abundant salts). Evaporites also were deposited some 100 million years ago in the equatorial regions of the South Atlantic during the early opening of this ocean.