Determination of calcite and dolomite content in soils and paleosols by continuous coulometric titration

Quantitative determination of calcite/dolomite ratios in soil carbonate fractions is important for understanding the pedogenic history of a soil or paleosol. This is particularly relevant to stable carbonate-carbon and -oxygen isotope analyses where the presence of dolomite in a carbonate fraction can lead to erroneous results and inaccurate interpretations of the paleoenvironment. The goal of this work was to develop and test an accurate method using coulometric titration combined with differential kinetic principles for determining calcite and dolomite fractions in a sample. An automated titrator was connected to a temperature-controlled carbonate reactor where 2 M HClO(4) was introduced to the sample and mixed by bubbling CO(2)-free air at a constant rate of 100 mL min(-1). Samples were ground to