The OCD (Oxygen, Carbon, Δ47) models are tools to investigate mechanisms of isotopic fractionation between CaCO3 minerals (inorganic or biogenic) and water. The latest version calculates the oxygen, carbon and clumped isotope ratio/value (δ18O, δ13C, Δ47, Δ48 and Δ49) of CaCO3 as a function of the solution temperature, mineral growth rate and the solution chemistry (i.e. pH, salinity, [DIC], [Ca2+] and the activity of the enzyme carbonic anhydrase). The mathematical models behind these calculations are presented in details in the following papers:
Devriendt L. S. et al. (2017) Oxygen isotope fractionation in the CaCO3-DIC-H2O system. GCA
Watkins J.M. and Devriendt L.S. (2022) A Combined Model for Kinetic Clumped Isotope Effects in the CaCO3-DIC-H2O System. G3
Please contact me (LSDevriendt#lbl.gov) if you would like access to the BASIC (Excel) or R codes.