Calculation of the conodont Color Alteration Index (CAI) for complex thermal histories

A simple model for the Arrhenius reaction conodont Color Alteration Index (CAI) that can be implemented easily in a computer program is introduced. The model, named to as EasyCAI, envisages the overall process of conodont alteration as a series of 12 parallel pseudo-first-order reactions. Our approach is especially amenable to a spreadsheet program and can solve complex geological histories involving variable heating and cooling rates. With EasyCAI, a profile of CAI values versus time can be obtained for a given stratigraphic level if the time–temperature history for that level has been estimated. EasyCAI can provide additional constraints to optimize thermal history models by computing profiles of CAI values with depth and time; thus providing a new tool for quantitative CAI palaeothermometric analysis.