Researchers have discovered a 400-mile-long chain of extinct, fossilized volcanoes buried deep below South China. The volcanoes formed when two tectonic plates collided during the breakup of the supercontinent Rodinia hundreds of millions of years ago, the scientists reported in a new study. The ancient volcanoes extend the region of past volcanism in this area by several hundred miles and may have affected Earth's climate.
About 800 million years ago, during the early Neoproterozoic era, South China sat at the northwestern margin of Rodinia. Shifting plate tectonics caused this area to break off into what is now the Yangtze Block plate, pushing it toward the China Ocean plate. As the two plates collided, the denser oceanic crust sank beneath the more buoyant continental crust and slid deep into Earth — a process known as subduction.
