HOUSTON, TEXAS — In a study published in Nature Communications, geologists from the University of Houston explained that magma had welled up under the Galapagos islands millions of years ago.
This hot rock was blocked off from the Caribbean by a curtain of subduction plate.
However, around 8.5 million years ago, a gateway opened in the subduction plate, allowing the hot material to flow through the foundations of Central America and into the area under the Caribbean Sea.
Today, this hot material reaches halfway to the Lesser Antilles islands, tilting the bottom of the sea by about 300 meters.
Geologists have long thought tectonic plates move because they are pulled by the weight of their sinking portions, and that an underlying, hot, softer layer called the asthenosphere serves as a passive lubricant.
However, this new study suggests that, in the Caribbean, the asthenosphere is not just a lubricant but acts more like a strong current that moves the floating plates around — a bit like the air currents of an air hockey table would move the pucks around when no one's playing.