SummaryThe value of modem commercial DTA equipment in the identification and determination of anhydrous carbonate minerals can be greatly improved by incorporating a controlled‐atmosphere (carbon dioxide) technique. The unproved peak definition and increased height enables the detection of carbonate minerals at concentrations of the order of 0.25 per cent by weight in a 50 mg sample. Further, the related changes in temperature of the decomposition reaction peaks provide additional information for the identification of carbonate mineral reactions. The method has particular application in mineralogical and pedological investigation