@WFS,World Fosssil Society,Riffin T Sajeev,Russel T Sajeev Spherical, isolated carbonate concretions occur throughout the world in marine argillaceous sedimentary rocks of widely varying geological ages. These concretions are characteristically highly enriched in CaCO3compared to the surrounding sedimentary rock matrices and are typically separated from these rock matrices by sharp boundaries1,2,3. These sharp boundaries mean that […]