Scientists long wondered whether there were places on Earth where extremely hot material from the core of the Earth moves up through the mantle, and if these plumes were responsible for some volcanic hotspots. In recent years, this theory seems to have been confirmed with seismic data. The Louisville hotspot is one such place. It sits in the southern Pacific Ocean, and hot, dynamic material from the Earth's core moves up to form volcanoes.
Researchers have now linked volcanic activity at the Louisville hotspot to the formation of a line of underwater mountains known as the Louisville Ridge, as well as a 120-million-year-old seafloor platform called the Ontong-Java Plateau. This plateau is the largest volcanic platform on the planet and it sits north of the Solomon Islands. The findings have been reported in Nature.
"Up until now, we've had this extremely disconnected picture of the Pacific and its volcanoes," noted corresponding study author Val Finlayson, an assistant research scientist at the University of Maryland. "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."
Tectonic activity in the Pacific has pushed a lot of the evidence linking Louisville and Ontong-Java under tectonic plates, Finlayson continued. "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."
After an analysis of the chemical composition and age of underwater mountains around Samoa, the researchers determined that they were far older than anticipated compared to volcanoes in the region. These mountains are part of an older portion of the Louisville hotspot.
Now that the data they obtained has improve their models, the team wants to learn more about volcanoes of the ocean. There are many island nations that are above volcanic platforms, and the researchers want to investigate the foundations of these places, as well as the evolution of geology and volcanoes around the world.
"We've solved one mystery, but there are countless more waiting to be unraveled. This finding offers us a more accurate history of the Pacific and its volcanic activity and helps us understand more about the dynamics and style of volcanism that occurs there," Finlayson said. "Everything new we learn about the Earth's tumultuous past helps us better understand the dynamic planet we live on today."
Sources: University of Maryland, Nature
