Fe analyses may be reported either as total iron or as explicit ferrous (Fe2+) or ferric (Fe3+) values.  Sometimes Fe data must be in a specific format before samples can be displayed on a classification diagram.  To make sure that ioGAS uses the correct column values the following aliases are available:

          ·       Fe – Total Fe

          ·       Fe2O3 – Total ferric (3+) oxide

          ·       FeO – Total ferrous (2+) oxide

          ·       Fe2O3* – Explicit ferric (3+) oxide

          ·       FeO* – Explicit ferrous (2+) oxide

Diagrams which require an Fe component in most cases will have a (Total Iron) and an explicit (Fe2+_Fe3+) version to choose from.  The (Total Iron) version requires one of Fe, Fe2O3 or FeO to be aliased. The (Fe2+_Fe3+) version requires two Fe columns of data to be aliased to Fe2O3* and FeO* otherwise the calculation or diagram will be greyed out.

It is possible to calculate explicit Fe2+ or Fe3+ values from total Fe values (and vice versa) using a variety of methods, some of which can be found under the Calculations menu.  Use these calculations to converted data into the correct Fe format required.