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
Ocean surface topography Ocean surface topography Ocean surface topography or sea surface topography, also called dynamic topography, are highs and lows on the ocean surface, similar to the hills and valleys of Earth's land surface depicted on a topographic map. These variations are expressed in terms of sea surface height (SSH) relative to the Earth's geoid. The main purpose of measuring ocean surface topography is to understand the large-scale circulation of the ocean. Unaveraged or instantaneous sea surface height (SSH) is most obviously affected by the tidal forces of the Moon and the Sun acting on the Earth. Over longer timescales, SSH is