THDYCT is a FORTRAN 77 library of parametrisations of stoichiometric constants as a function of temperature, salinity and pressure, relevant to the carbonate system. It also includes a subroutine to perform carbonate system speciation calculations using the AlkCB approximation to AltT. The fundamentals are described in G. Munhoven. Modelling Glacial-Interglacial Atmospheric CO2 Variations: The Role of Continental Weathering. Université de Liège, 1997. URL: http://hdl.handle.net/2268/161314. THDYCT is a prerequisite to the standard versions of several applications of the sediment model MEDUSA v. 2 (Model of Early Diagenesis in the Upper Sediment with Adaptable complexity, version 2). THDYCT is, however, entirely independent of that particular project.

Financial support for this work was provided by the Belgian National Fund for Scientific Research F.R.S.-FNRS, with which Guy Munhoven is a Research Associate.