The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, bounded by Asia and Australia in the west, and the Americas in the east. The Pacific Ocean developed from the Panthalassic Ocean following the breakup of Pangaea. There is no firm date for when the changeover occurred, as the replacement of the sea bed is a continuous process, though reconstruction maps often change the name from Panthalassic to Pacific around the time the Atlantic Ocean began to open.[5][6][7] The Panthalassic Ocean first opened 750 million years ago at the breakup of Rodinia,[7] but the oldest Pacific Ocean floor is only around 180 Ma old. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs, and uplifted coral platforms. (Wikipedia)