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Earth’s Magmatic Heart May Be Beating

New information about the youngest plutonic rocks found on the Earth will help to pinpoint the timing and recurrence of major magmatic pulses beneath the planet’s surface, according to a study published in Scientific Reports.

The research suggests that plutons – the crystallised remnants of magma chambers deep underground – form every 700,000 years within the Hida Mountains of central Japan. This suggests that the next big magmatic pulse may already be happening.

Lead researcher Dr Christopher Spencer of the WA School of Mines at Curtin University said the research provides critical insights into understanding how volcanic systems are connected to pulses beneath the Earth’s surface. “The Hida Mountain range in Japan contains the youngest exposed plutonic rocks on Earth, and provided us with a unique opportunity to assess the different characteristics of the tempo of magmatism, or the movement of magma, deep in the Earth,” he said.

“Our ability to distinguish two closely-spaced magmatic pulses becomes much more difficult the longer we look back into history, but this discovery now allows us to investigate these instances that otherwise might have been left unanswered.”

Spencer said Japan is an ideal location for this research because the magmatism seen in the Hida Mountains falls within a similar time scale as other volcanic systems around the world. “It has been over 700,000 years since the last major magmatic activity in the area, and this work may indicate that more magmatism is forming deep in the Japanese crust at this very moment,” he said.

“By analysing the timing and speed of the magmatic pulses deep beneath the surface of the volcanoes, we are able to understand how these systems work from top to bottom. The more we know about the tempo of magma formation deep within the volcanoes, the better we can understand the nature of volcanic activity around the world.”