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
Sistan Basin Mount Khajeh, rises beside the lakes and marshes of the basin. The lowest part of the Sistan Basin contains a series of shallow lakes, known as "hamuns". It appears that in the past there was a single Hamun Lake, but there are now three separate lakes. From north to south the lakes are: The Hamun-e Puzak lies mostly in Afghanistan. It receives water from the Shelah Charkh channel of the Helmand River, and also from the Khash River and other small rivers. The Hamun-e Sabari is split between Iran and Afghanistan. It receives water from the Parian branch of Helmand