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
Nansen Island (Kara Sea) and some of its larger neighboring islands, such as Taymyra, Bonevi and Pilota Makhotkina, are deeply indented, with many crooked inlets. The sounds between this island and neighboring islands are also somewhat labyrinthic. Geologically all these coastal islands are a continuation of the Nordenskiöld Archipelago which lies further north. And sometimes Nansen Island is considered a part of it. Ostrov Vkhodnoy is a long islet located off Nansena's western end. The sea surrounding Nansen Island is covered with pack ice with some polynias during the long and bitter winters and there are many ice floes even in the summer. Nansen