Geology of the Pacific Ocean . The Pacific Ocean developed from the Panthalassa, a vast global ocean, following the breakup of the supercontinent Pangaea in the Mesozoic Era, gradually forming Gondwana and Laurasia, which in turn divided. 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. The Panthalassic Ocean first opened around 750 million years ago at the breakup of Rodinia, but the oldest Pacific Ocean floor is only around 180 Ma old.
Gondwana formation of Gondwana began with the East African Orogeny – the collision of India and Madagascar with East Africa – and was completed with the overlapping Brasiliano and Kuunga orogenies – the collision of South America with Africa and the addition of Australia and Antarctica, respectively. The continent of Gondwana was named by Austrian scientist Eduard Suess, after the Gondwana region of central India which is derived from Sanskrit for "forest of the Gonds". The name had been previously used in a geological context, first by H.B. Medlicott in 1872, from which the Gondwana sedimentary sequences (Permian-Triassic) are also described.