A new discovery says earth has been swallowing more carbon than previously thought. The findings say that the carbon drawn into Earth’s interior at subduction zones, where tectonic plates collide and dive into Earth’s interior – tends to stay locked away at depth, rather than resurfacing in the form of volcanic emissions. The up to date findings point out that round a 3rd of carbon rolled into Earth’s inside stays locked away long run. Previously, it was thought that the majority of it reappeared by way of volcanic eruptions.
The deep carbon stores play a key role in maintaining the habitability of our planet by regulating atmospheric CO2 levels. There are a number of ways for carbon to be released back to the atmosphere (as CO2) but there is only one path in which it can return to the Earth’s interior, that is plate subduction.
Specifically, the team found that carbonate rocks become less calcium-rich and more magnesium-rich when channelled deeper into the mantle – that makes them less soluble, and less likely to be drawn into the fluids supplying volcanoes. Instead, the majority of the carbonate apparently sinks deeper, and can eventually turn into diamond – taking the carbon gathered from the atmosphere, via ocean sediments, along with it.10:43 28-07-2021
The team conducted a series of experiments at the European Synchrotron Radiation Facility. To replicate the high pressures and temperatures of subductions zones, they used a heated ‘diamond anvil’, in which extreme pressures are achieved by pressing two tiny diamond anvils against the sample.