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 Observatories Initiative the ocean from physical, chemical and biological perspectives. Lithospheric movements and interactions at plate boundaries at or beneath the seafloor are responsible for short-term events such as earthquakes, tsunamis and volcanic eruptions. These regions are also host to the densest hydrothermal and biological activity in the ocean basins. The oceanic crust contains the largest aquifer on Earth. Thermal circulation and reactivity of seawater-derived fluids can modify the composition of oceanic plates, lead to the formation of hydrothermal vents that support unique micro- and macro-biological communities and concentrate methane to form massive methane gas and methane hydrate reservoirs. The four main