Congratulations to Mingda Lv and the rest of our team on our new paper in Nature Communications out yesterday, “Reversal of carbonate-silicate cation exchange in cold slabs in Earth’s lower mantle.” In this study, we follow up on our previous work that determined calcium carbonate is more resistant than magnesium carbonate to reduction to diamond in the reduced deep lower mantle, asking the key question, “but what happens to these carbonates in contact with deep mantle silicates?” Although magnesium carbonate was thought to be the dominant host for oxidized carbon in the mantle, by pushing all the way to core-mantle boundary pressure/temperature conditions, Mingda determined that calcium carbonate again becomes more stable. This allows us to predict a signature of oxidized, subducted carbon that could be found in diamonds formed in the lowermost mantle.

The work is featured today on the front page of the MSU College of Natural Sciences!