Tectonic link found between Ontong Java Plateau and Louisville hotspot chain

Researchers from the University of Maryland and the University of Hawaiʻi have identified a shared origin for two massive volcanic features in the Pacific, linking them to a single hotspot beneath the ocean floor.

Their findings suggest that this deep-seated heat source was responsible for creating both the vast Ontong Java Plateau and a long trail of underwater volcanoes across the southern Pacific. To provide a clearer picture, this finding has unified what were once considered two separate geological events.

Valerie Finlayson, affiliated with the University of Maryland’s Department of Geology, who also served as the corresponding author on the project, explained that scientists had long viewed Pacific volcanoes as isolated features.

“But for the first time, we’re able to make a clear connection between the younger southern and older western Pacific volcanic systems. It’s a discovery that gives us a more complete history of how the Pacific Ocean basin has evolved over millions of years to become what it is today,” Valerie added.

Researchers and geologists have speculated for a long time whether the Louisville hotspot in the southern Pacific contributed to the formation of the eponymous volcanic chain and the Ontong Java Plateau. This hotspot is presumably where heat and material from deep within the Earth rise to form volcanoes.

Previous theories on the movement of the Pacific seafloor attempted to establish a connection between these two geological formations, but none were able to provide a clear and definitive answer.

Finlayson explained that much of the physical evidence linking the Louisville hotspot to the Ontong-Java Plateau has been lost due to part of the Louisville hotspot track being subducted beneath tectonic plates in the Pacific. To uncover evidence from tens of millions of years ago, the team had to sample deeply submerged volcanoes along a different long-lived hotspot track. Their new findings rendered their previous beliefs obsolete.

During their research near Samoa, Finlayson’s group identified a group of seamounts that appeared far older than the usual volcanic features in that part of the Pacific. Laboratory testing of the rocks’ geochemical properties and age pointed to a connection with an ancient stretch of the Louisville hotspot trail.

Geologists described these features as traces left behind by a volcano, created when the tectonic plate drifted slowly over a stable heat source deep within the Earth. Volcanic trails can be traced back through time with the logic that older formations are found farther from the active hotspot.

The new evidence helped the team revise their models of Pacific plate movement, giving them a clearer picture of long-term changes in the seafloor. Since many Pacific island nations sit on volcanic platforms and underwater chains, this research is expected to shed light on the geological foundations that shape these islands.

Building on their findings, Finlayson’s team plans to further apply their revised models to study other volcanic structures around the world.

References:

¹ Pacific hotspots reveal a Louisville–Ontong Java Nui tectonic link – Konter, J.G., Finlayson, V.A., Konrad, K. et al. – Nature 641, 388–394 (2025). – DOI https://doi.org/10.1038/s41586-025-08889-0

² Researchers Solve One of Earth’s Ancient Volcanic Mysteries – University of Maryland – April 30, 2025

Harsh Vardhan

My passions include trying my best to save a dying planet, be it through carpooling or by spreading awareness about it. Research comes naturally to me, complemented by a keen interest in writing and journalism. Guided by a curious mind and a drive to look beyond the surface, I strive to bring thoughtful attention and clarity to subjects across Earth, sciences, environment, and everything in between.

This author does not have any more posts.