Calcite Cleats in Coal

Coal deposits in the Transantarctic Mountains contain carbonate minerals (calcite and siderite) in the form of 

Samples of calcite and the associated coal from several locations in sonthern Victoria Land were analyzed by Fanre and Botoman (1984) for the isotope compositions of carbon, oxygen, and strontium. The objectives of this study were to derive information about the environmental conditions in which the calcite cleats formed and to determine the provenance of the carbon and strontium they contain. The results are listed in Table 11.4. 

The 6 C values of the coal samples range from -23.5%o to -26.7%o on the PDB scale which means that the coal was strongly depleted in C by photosynthesis of the plants from which the coal formed. The carbon in the calcite is also depleted in C as indicated by 8 Kl values ranging from -15.6%o to-16.9%o. Evidently, most but not aU, of the carbon in the calcite originated 

The bicarbonate ions that were derived from the coal mixed with bicarbonate ions that had formed from atmospheric carbon dioxide which has 5 C = -7.7%o(PDB). The fraction of carbon in the calcite can be estimated from mixing theory (Eaure and Mensing 2005)  

Taking the 5 values of the calcite and coal in the Allan Hills (Table 11.4) yields  

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