Computer programs for the classification and nomenclature of igneous rocks

Abstract

We review the most important computer programs for the classification of igneous rocks and point out those that follow the recommendations of the International Union of Geological Sciences (IUGS). A new program Igneous Rock Classification System (IgRoCS), written in Visual Basic, is then described in detail. IgRoCS allows the user to follow strictly the IUGS classification and nomenclature scheme for igneous rocks. The special rocks are first classified, then plutonic rocks are named after the IUGS mineralogical classification, next high-Mg and picritic volcanic rocks are identified from the IUGS criteria, and finally other volcanic rocks are classified according to the TAS diagram and CIPW norm. The chemical classification of volcanic rocks can also be achieved directly without going through the classification of other rock types. The IgRoCS program incorporates the revised standard igneous norm. Thus, the use of this new software is encouraged for a strict application of the IUGS recommendations for igneous rock classification and nomenclature.