"mineral processing approach using carbon dioxide to promote mineral alterations that lead to improved extractability of nickel from olivine ((Mg,Fe)2SiO4)"

"main products of the carbonation reaction include quasi-amorphous colloidal silica, chromium-rich metallic particles, and ferro-magnesite ((Mg1−x,Fex)CO3)"

https://www.mdpi.com/2075-4701/5/3/1620/htm

Olivine rock usually contains those elements.

And the scheme would involve many gigatons of olivine, so the release would be very large.