Experimental studies of oxygen isotope fractionation between rhodochrosite (MnCO3) and water at low temperatures

Rhodochrosite crystals were precipitated from Na–Mn–Cl–HCO3 parent solutions following passive, forced and combined passive-to-forced CO2 degassing methods. Forced and combined passive-to-forced CO2 degassing produced rhodochrosite crystals with a small non-equilibrium oxygen isotope effect whereas passive CO2 degassing protocols yielded rhodochrosite in apparent isotopic equilibrium with water. On the basis of the apparent equilibrium isotopic …