Borders of the oceans seas it contains) as follows: Note that these definitions exclude any marginal waterbodies that are separately defined by the IHO (such as the Kara Sea and East Siberian Sea), though these are usually considered to be part of the Arctic Ocean. The CIA defines the limits of the Arctic Ocean differently, as depicted in the map comparing its definition to the IHO's definition. The Atlantic Ocean separates the Americas from Europe and Africa. It may be further subdivided by the equator into northern and southern portions. The 3rd edition, currently in force, of the International Hydrographic Organization's (IHO) "Limits of
Tethys Ocean Western Tethys Ocean, or Paratethys or Alpine Tethys Ocean. The Black, Caspian, and Aral seas are thought to be its crustal remains, though the Black Sea may, in fact, be a remnant of the older Paleo-Tethys Ocean. The Western Tethys was not simply a single open ocean. It covered many small plates, Cretaceous island arcs, and microcontinents. Many small oceanic basins (Valais Ocean, Piemont-Liguria Ocean, Meliata Ocean) were separated from each other by continental terranes on the Alboran, Iberian, and Apulian plates. The high sea level in the Mesozoic flooded most of these continental domains, forming shallow seas. As theories