Researchers solve one of Earth's ancient volcanic mysteries

Researchers solve one of Earth's ancient volcanic mysteries
by Georgia Jiang
College Park, MD (SPX) May 01, 2025

Geologists led by the University of Maryland and the University of Hawaii finally connected the dots between one of the largest volcanic eruptions in Earth's history and its source deep beneath the Pacific Ocean.

In a paper published in the journal Nature on April 30, 2025, the team revealed that the same underwater hotspot created both a chain of underwater volcanoes in the southern Pacific region and the massive Ontong-Java Plateau, the largest volcanic platform on Earth.

"Up until now, we've had this extremely disconnected picture of the Pacific and its volcanoes," said the study's corresponding author Val Finlayson, an assistant research scientist in UMD's Department of Geology. "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."

For years, scientists wondered whether the southern Pacific Ocean's Louisville hotspot-an area where hot and chemically distinct material from deep inside the Earth rises to the surface to create volcanoes-formed both the underwater mountain chain bearing its name and the 120-million-year-old Ontong-Java Plateau, a submerged seafloor platform located what is now north of the Solomon Islands. Previous theories and models on how the Pacific seafloor moved attempted to explain the connection between the two major geological features but failed to provide a definitive answer.

"Much of the physical evidence for a connection between Louisville and Ontong-Java has disappeared because part of the Louisville hotspot track was subducted, or pushed, under tectonic plates in the Pacific region," Finlayson said. "We had to sample deeply submerged volcanoes from a different long-lived hotspot track to find evidence from tens of millions of years ago that suggested our models for the Pacific plate needed revision."

Finlayson and her team made their first breakthrough when they discovered a series of underwater mountains near Samoa that were much older than expected for volcanoes in the area. By analyzing the age and chemical makeup of ancient rock samples taken from the area,

Research Report:Pacific hotspots reveal a Louisville-Ontong Java Nui tectonic link