Scientists think they know why rocks from the Earth’s mantle are found more than 1,000 miles (1,609 kilometers) away from where they came from thanks to a geological “secret passage.”
In the mantle, there is an opening about 62 miles (100 km) below the Earth’s surface. Mantle materials can flow from the Galápagos Islands to the Panamanian coast through this opening.
This never-before-seen mode of transportation may also help explain why Panama doesn’t have many volcanoes that are still active.
In a new study, Bekaert and his team say that a window-like opening in the Cocos tectonic plate, which is being pushed down toward the center of the Earth, could be the reason.
To find out more, the researchers looked into the area’s geology. They took volcanic rock samples and gas and fluid samples from hot springs.
There are usually different types of geological materials coming from other places. “Panama and behind the volcanic arc in Costa Rica have some unique geochemical signatures,” Bekaert told Live Science; no one could figure out how mantle elements from the Galápagos could get all the way to Panama.
Eventually, researchers used seismic imaging of the mantle to see what was beneath the surface, and computer modelling to figure out what might be going on there as well.
In the Cocos buried under Panama, there is a hole in the slab that allows one to see through.
It could be a natural crack or a place where the crust snapped during subduction. Whatever way you look at it, it lets things move through, like a breeze going through an open window.
Researchers aren’t sure which of two things could be making these breezes. In the first place, they’re going to pass through the Panama Fracture Zone, which is a zone of cracks in the crust and upper mantle that connects the Galápagos Islands to Panama. It’s hard to figure out what would drive long-distance transportation through that zone. It’s not even clear if such a ride is even possible.
The second most likely scenario is that the typical, large-scale circulation of the mantle pushes materials through the gaps.
Again, a mantle window can help explain why there aren’t any active volcanoes in Panama. But there are still mysterious changes in the chemistry of the mantle all over the world. The team wants to do more research and dive deeper into the matter.