ABSTRACT

Many methods have been used to analyze carbonate rocks for calcite-dolomite content. One approach is based on the difference in density of the two minerals. In this study, volumes of about 50-gram samples of carbonates are determined with an air comparison pycnometer, and densities calculated. The precision (standard deviation) of the density determination is 0.0028. Replicate weighings, volume determinations, and density calculations are done within 5 minutes. Calcite-dolomite composition is found by reference to a calibration line constructed with the densities of calcite and dolomite as end members. The 98 percent confidence interval for an analysis is two percent. The density contribution of terrigenous material present should be taken into account. This method is sufficiently pre ise and accurate for most purposes. It has, in addition, the advantage of being simple, very rapid, and relatively inexpensive.