New computer program TecD for tectonomagmatic discrimination from discriminant function diagrams for basic and ultrabasic magmas and its application to ancient rocks.

Abstract

Due to the unavailability of suitable software, a new computer program TecD (Tectonomagmatic Discrimination) was written in Visual Basic for using four sets of new discriminant function based diagrams published during 2004-2011. This bilingual (both in English and Spanish) program evaluates igneous rock geochemistry data in 20 different multi-dimensional diagrams (4 sets of 5 diagrams each), automatically counts the number of samples plotting in different tectonic fields, computes success rates (%) for a given area or set of rock samples, provides scalable vector diagrams that can be opened and modified in different commercial software, and presents a synthesis of this application in a final report. Three examples are presented to highlight the use of TecD. Ocean island setting is inferred for ~56 Ma basic rocks from Faroe Islands (Atlantic Ocean), mid-ocean ridge for ~2700 Ma Archean Abitibi greenstone belt (Canada), and arc setting for ~2950 Ma Mallina basin (Australia). Additional criteria for the interpretation of these diagrams are also briefly discussed.