Lord Howe Island's twin volcano chain formed from one hotspot
A single mantle plume split in two to create two parallel undersea volcano chains stretching 1,500 kilometres along Australia's east coast.
Lord Howe Island, the dramatic World Heritage site about 600 kilometres off the NSW coast, is part of a much larger underwater volcanic system. Scientists thought two separate chains of mostly submerged volcanoes formed separately: the Lord Howe seamount chain and the Tasmantid chain.
The two chains ran parallel less than 1,000 kilometres apart. A new study shows they came from the same source.
Researchers built a 3D model. It showed a single hotspot plume moved up from Earth's interior over more than 40 million years.
When it hit a slab of old seafloor 500 kilometres deep, the plume could not go straight up. So it split in two.
Each branch created one volcanic chain. Rock samples from both chains proved chemically near identical for any given age, confirming the shared origin.
- 1,500 kilometres
- Chain length
- 600 kilometres
- Distance offshore
- Less than 1,000 kilometres
- Chain separation
- 40 million years
- Geological timescale
Why it mattersThe finding reveals how Earth's interior works and how continents have moved over deep time, tools scientists use to map global geology and test theories about other volcanic chains worldwide.
AustraliaLord Howe Island is an Australian World Heritage site with unique plants and animals. Understanding its volcanic origins helps explain Australia's geological history and the forces that shaped the east coast.
✓ Claims checked against the source and corrected before publish. checked 2 h ago
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