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
Largest organisms over . The largest organism in the world, according to mass, is the aspen tree whose colonies of clones can grow up to five miles long. The largest such colony is Pando, in the Fishlake National Forest in Utah. Another form of flowering plant that rivals Pando as the largest organism on earth in breadth, if not mass, is the giant marine plant, "Posidonia oceanica", discovered in the Mediterranean near the Balearic Islands, Spain. Its length is about . It may also be the oldest living organism in the world, with an estimated age of 100,000 years. Green algae are