Geology of the Pacific Ocean Geology of the Pacific Ocean The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific Plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth. The tectonic plates continue to move today. The slowest spreading ridge is the Gakkel Ridge on the Arctic Ocean floor, which spreads at less than , while the fastest, the East Pacific Rise near Easter Island, has a spreading rate of over
Fridtjof Nansen like a spiral staircase, down towards the depths". In 1909 Nansen combined with Bjørn Helland-Hansen to publish an academic paper, "The Norwegian Sea: its Physical Oceanography", based on the "Michael Sars" voyage of 1900. Nansen had by now retired from polar exploration, the decisive step being his release of "Fram" to fellow Norwegian Roald Amundsen, who was planning a North Pole expedition. When Amundsen made his controversial change of plan and set out for the South Pole, Nansen stood by him. Between 1910 and 1914, Nansen participated in several oceanographic voyages. In 1910, aboard the Norwegian naval vessel "Fridtjof", he