Geology of the Pacific Ocean

[4] Charles Darwin proposed a theory that explained the existence of reefs by means of slow subsidence of the ocean floor.

[5] In the Early Jurassic, the supercontinent Pangaea was surrounded by the superocean Panthalassa, the ocean floor of which was composed of the Izanagi, Farallon, and Phoenix plates.

Virtually all of the three Panthalassic plates have now been subducted beneath surrounding continents but their spreading rates have been preserved in the magnetic lineations around the Pacific Triangle.

Atolls have developed in tropical waters when, after volcanoes sink, coral growth results in reefs as evidenced by the Cook Islands.

South of Japan, the Izu-Bonin and Mariana island arcs (IBM) formed in front of a clockwise rotating Philippine Sea plate.

The IBM trenches began to grow in length c. 40 million years ago, opening back-arc basins in the Philippine Sea.

[13] In the western and southwestern Pacific, continental blocks and back-arc basins form one of the most complex regions on earth stretching from Japan to New Zealand.

Zealandia which broke off from Gondwana 70 million years ago with the spreading of the Tasman Sea, has since resulted in island protrusions such as New Zealand and New Caledonia.

In 2009, the deepest undersea eruption ever recorded occurred at the West Mata submarine volcano, a mile beneath the ocean, close to the Tonga-Kermadec Trench, within the Ring of Fire;[17] it was filmed by the US Jason robotic submersible which descended over 1,100 metres (3,600 ft).