Slow-Motion Tectonic Plate Collisions Force More Carbon Into The Earth's Interior

Scientists from Cambridge University and NTU Singapore have made an interesting discovery. They found that slow-motion collisions of massive tectonic plates inside the Earth are dragging more carbon into Earth's interior than previously believed. Researchers say that the carbon is drawn into the planet's interior at subduction zones where tectonic plates collide and dive into the interior of the Earth.

Carbon drawn into the Earth's interior at the zones tends to stay locked away depth rather than resurfacing in the form of volcanic emissions. The findings in the study suggested only about a third of the carbon recycled beneath volcanic chains returns to the surface via recycling. This is a significant and marked difference in previous theories that suggested carbon that goes into the interior of the Earth mostly comes back up.

The team believes by studying how carbon behaves deep inside the Earth where most of the planet's carbon is stored, we can better understand the entire lifecycle of carbon on Earth. Better understanding that lifecycle sheds new details on how carbon flows between the atmosphere, oceans, and life on the planet's surface. Currently, the most understood parts of the carbon cycle are at or near the planet's surface, but deep carbon stores play a key role in maintaining the habitability of our planet by regulating atmospheric CO2 levels.

Study lead author Stefan Farsang says we have a relatively good understanding of surface reservoirs of carbon and the fluxes between them, but less is known about the interior carbon stores of Earth, which cycle carbon over millions of years. There are many ways for carbon to be released back to the atmosphere as carbon dioxide, but only one path for her to return to the Earth's interior. That path is via plates induction. In that path, surface carbon in the form of seashells and microorganisms that have locked atmospheric carbon dioxide in their shells is channeled into the Earth's interior.

Scientists previously believed much of that carbon was returned to the atmosphere as carbon dioxide via emissions from volcanoes. However, the new study has found chemical reactions taking place in rocks swallowed up at subduction zones trap carbon and send it deeper into the Earth's interior, stopping some of it from coming back to the surface.