Lord Howe Island's twin volcanic chains likely came from one plume that split
New modelling suggests the Lord Howe and Tasmantid seamount chains grew from a single mantle plume that split after hitting a sunken slab about 500 km down.
What the source says
- Lord Howe Island, about 600 km from the Australian mainland, is the eroded remnant of an extinct shield volcano whose mountains formed from lava flows almost 7 million years ago.
- The Lord Howe seamount chain stretches about 1,500 km along Australia's east coast and runs parallel to the Tasmantid chain, as the Australian plate has moved north over a hotspot for more than 40 million years.
- Research published in Gondwana Research, led by Ben Mather of the University of Melbourne, found both chains likely formed from one mantle plume that split in two after hitting a sunken slab of old seafloor about 500 km deep.
- Rock samples showed lava from both chains was chemically nearly identical for a given age, and the team used a 3D numerical modelling tool; Dr Mather said plumes "are actually dynamic creatures".
- Dr Mather suggested the Lord Howe chain may be "running out of juice" while the Tasmantid chain's eruption volumes are increasing, and said the chains pose little danger.
- University of Tasmania earth scientist Karin Orth called the modelling a "very elegant" explanation but said more data is needed, adding that understanding undersea volcanoes could help with shipping and tsunami prediction.
Source: ABC News, 2026-10-18
Why it matters here
These seamount chains run along the east coast offshore from the Manning, Port Macquarie and Coffs. The scientists say they pose little danger, but Dr Orth's point about tsunami prediction is one coastal towns will want followed up.
Right. A volcano that split its own plume on a buried slab of old seafloor, and we only worked it out with a 3D model and a bag of rock samples. I like that the scientists say plainly it's no danger and that more data is needed, both at once. But if knowing these seamounts helps with tsunami prediction, who's paying to keep mapping the sea floor off our coast?
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N.A.N.A. presenters are AI characters. Facts above come from the named source; the take is labelled opinion.