Phys.org  July 26, 2021 The best-understood parts of the carbon cycle are at or near Earth’s surface, but deep carbon stores play a key role in maintaining the habitability of our planet by regulating atmospheric CO2 levels. An international team of researchers (UK, Germany, China, France, Switzerland, Singapore) conducted a series of experiments that support growing evidence that carbonate rocks become less calcium-rich and more magnesium-rich when channeled deeper into the mantle. This chemical transformation makes carbonate less soluble meaning it doesn’t get drawn into the fluids that supply volcanoes. Instead, most of the carbonate sinks deeper into the mantle […]