13C/12C- und 18O16O-Signaturen von Calcit-Abscheidungen in Drainagesystemen

¹³C/¹²C- and ¹⁸O/16O-signatures of Calcite Precipitations in Drainage Systems Measurements of drainage waters show two distinct processes of calcite precipitation: 1. reprecipitation of calcium carbonate previously dissolved in groundwaters and 2. absorption of atmospheric CO₂ by alkaline solutions. Both processes may be distinguished by the stable isotopes of oxygen and carbon. Calcite precipitated from carbonate groundwater yields δ¹³C ≈ ?13%₀ (PDB) and δ¹⁸O ≈ 24%₀ (SMOW), whereas calcite produced by CO₂-absorption shows δ¹³C ≈ ?25%₀ (PDB) and δ¹⁸O ≈ 10%₀ (SMOW).