Feb. 27 (UPI) -- New research suggests the Hawaiian hotspot migrated southward between 50 and 60 million years ago.
Hotspots describe a concentration of molten tunnels, allowing magma from deep in the mantle a direct path through Earth's crust to the surface, where the molten rock forms volcanoes.
The concept of the volcanic hotspot has been used to account for the creation of the Hawaiian Islands, the youngest members of the Hawaiian-Emperor chain of volcanic islands. Most models that simulate the evolution of the Hawaiian-Emperor chain operate under the assumption that hotspots are stationary, and that the movement of tectonic plates drives the evolution of chains of volcanic islands.
But new research suggests a complicated scenario, one in which the hotspot is also on the move.
If the movement of the Pacific plate was the only driver of the Hawaiian-Emperor chain, then the string of islands should follow a fairly predictable path. But some 47 million years ago, the chain took a left turn as it shifted southward, creating a 60 degree bend.
"If you try to explain this bend with just a sudden change in the movement of the Pacific Plate, you would expect a significantly different direction of motion at that time relative to adjacent tectonic plates," Bernhard Steinberger, a researcher with the GFZ German Research Center for Geosciences, said in a news release. "But we have not found any evidence for that."
To put the evolution of the Hawaiian-Emperor chain in proper context, Steinberger and his colleagues used updated rock dating data from the Rurutu volcanic chain in the Western Pacific, as well as the Louisville chain in the Southern Pacific.
The new data helped scientists better understand how the positioning of the three hotspots have moved relative to each other over time. Their findings -- published in the journal Nature Communications -- suggest the Hawaiian hotspot moved relative to the other hotspots between 50 and 60 million years ago.
"This makes it very likely that mainly the Hawaii hotspot has moved," said Steinberger.
The updated models suggests the Hawaiian hotspot migrated southward at a rate of several dozen miles per million years.
"Our models for the motion of the Pacific Plate and the hotspots therein still have some inaccuracies," Steinberger said. "With more field data and information about the processes deep in the mantle, we hope to explain in more detail how the bend in the Hawaiian-Emperor chain has evolved."