A group of Japanese scientists found an underwater fine-grained volcano about 3 million years old. It was discovered in one of the oldest parts of the Pacific Plate.
Eruptions of alkaline magma can form small volcanoes on oceanic plates. The first such volcanoes in 2006 were found in the Japanese Trench, an oceanic depression in the west of the Pacific Ocean, east of Honshu Island. Now, researchers have discovered a new volcano, which appeared about 3 million years ago. It is located next to Minamitori Island in the northwestern Pacific Ocean.
“These are small volcanoes that occur along cracks forming at the base of tectonic plates,” said Naoto Hirano of the Center for North-East Asian Studies. - As tectonic plates sink into the upper mantle of the Earth, cracks occur in which the plate begins to bend, causing an eruption of these volcanoes.
In this case, magma erupts directly from the asthenosphere - the upper part of the mantle, which controls the movement of tectonic plates. Researchers noted that studying fine-grained volcanoes can provide more information about the asthenosphere, giving scientists a deeper understanding of plate tectonics, the types of rocks that exist there, and the melting process under tectonic plates.
“The discovery of a new volcano provides us with an excellent opportunity to further explore this area. However, to gain more extensive knowledge, we hope to discover several more similar volcanoes in 2020,” the researchers noted.