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
1998–99 South-West Indian Ocean cyclone season 1998–99 South-West Indian Ocean cyclone season The 1998–99 South-West Indian Ocean cyclone season was a quiet season that had the fourth-lowest number of days with tropical storm or tropical cyclone activity. Most of the storms formed either in the Mozambique Channel or in the far eastern portion of the basin, with five storms crossing from the adjacent Australian basin east of 90° E. As a result, few storms impacted Madagascar, and none made landfall on the African continent. Throughout most of the season, there was below-normal sea surface temperatures in the Indian Ocean east of Madagascar. In February, typically the