This secret channel could explain why rocks from Earth’s mantle were located 1,609 km further from their origin.
Geologists have uncovered a geological secret route beneath the country that could explain why rocks from the Earth’s mantle were found 1,609 kilometers away from their origin.
This entry point, roughly 100 km below the surface of the Earth, might allow a flow of mantle elements from the Galapagos to Panama.
And it may also explain why Panama has so few active volcanoes, according to David Bekaert of the Woods Hole Oceanographic Institution in Massachusetts.
This process of subduction occurs when oceanic crust moves beneath continental crust on the West Coast of Central America, pushing oceanic crust under the continental crust of the North American tectonic plates, Caribbean and Panama tectonic plates.
This is known to create a sort of ‘subduction zone,’ and by extension, the formation of a line of volcanoes known as the Centra American Volcanic Arc, where lava pushes over the boundaries, only to end in western Panama, above the Panama Plate.
Researchers suggest in their paper published in PNAS that the culprit could be a window-like opening in Coco’s tectonic plate that is being pushed towards the center of the Earth.
To further understand the region’s geochemistry, researchers gathered volcanic rock samples and hot spring gas and fluid samples.
They were interested in ratios of molecular isotopes — atoms with various quantities of neutrons in their nuclei. They focused on helium and lead isotopes in this case.
They were particularly interested in molecular isotope ratios, which are essentially variations of the same atom with various nuclei containing different numbers of neutrons. In this case, they focused on helium and lead isotopes.
“We found that in particular places of Central America, namely western Panama and behind the volcanic arc in Costa Rica, we have some exotic signatures [of geochemistry] that really resemble what you have in the Galápagos Islands,” Bekaert told LiveScience.
This was unexpected, according to Bekaert, because there was no alternative way for mantle components from the Galapagos to reach Panama. Seismic imaging of the mantle, which utilizes earthquake waves to identify what’s beneath the surface, revealed a hole deep beneath Panama through which the mantle surfaces.
This could be a natural crack in the subducting Coco’s crust or a crust snap during subduction. As with an open window, it allows materials to pass from one side of the plate to the other.
However, scientists are unsure what is causing this shift. Large-scale mantle circulation may drive material through the subducting slab’s opening, they believe. They say that once the mantle circulation modeling is finished, the deep global mantle will flow.
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