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
Argentine Basin Antarctic Bottom Water current, which dominates the circulation in the abyssal layer of the southwest Atlantic, enters the southwest part of the Argentine Basin, then is deflected northward along the continental rise. It passes into the Brazil Basin through the Vema Channel (39° 30′ W) to the west of the Rio Grande Rise. Here, the current reaches velocities of 20–25 cm/s. Argentine Basin The Argentine Basin is a region of the Atlantic Ocean floor off the east coast of Argentina, between the Mid-Atlantic Ridge to the east and the Scotia Basin to the west. To the north is the Brazil