ABSTRACT

In order to elucidate the transformation of natural magnesian calcite to a more stable carbonate mineral, the present authors have studied the influence of magnesium ions in solution on the transformation through the dissolution experiment in the laboratory. Magnesian calcite in biological systems such as calcareous algae transforms into low-magnesian calcite in solutions containing no magnesium ions. In solution with magnesium ions, however, the transformation of magnesian calcite is inhibited and its magnesium carbonate content is increased owing to the dissolution of calcium carbonate portion. These results are useful or understanding the mineralogical change of carbonates in aquatic environment.