Calcium Carbonate Concretions Formed by the Decomposition of Organic Matter

摘要: Bacterial decomposition of butterfish and smelts in small sealed jars containing seawater other solutions, for periods ranging from 65 to 205 days, results a large increase concentrations dissolved bicarbonate, carbonate, ammonia (plus volatile amines). Accompanying this is rise pH the precipitation Ca++ ion solution. The not precipitated as CaCO3 but instead mixture calcium fatty acid salts or soaps with 14 18 carbon atoms. This can be explained by thermodynamic instability relative Ca presence excess free acid. It suggested that some ancient concretions, especially those enclosing fossils soft-bodied organisms, may have formed rapidly after death form natural soap (adipocere) which was later converted CaCO3.