Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf) Ternary Diagram: An Excellent Tool for Discriminating Barren and Ta-Hosting Granite-Pegmatite Systems

Abstract

Discriminating barren and fertile intrusions is one of the main challenges in the search for rare-element pegmatites. Diagrams comprising more than one element can make discrimination of productive and barren samples more valid. These diagrams distinguish samples by simultaneous means of positive and/or negative correlations between variables. A ternary diagram for S-type peraluminous granites has been obtained in this study. Firstly, a database composed of Ta-bearing and barren granitic systems was created, then geochemical behavior of trace elements was studied, and statistical investigations were done using GCDkit software, which resulted in the Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf) ternary diagram which can distinguish the non-mineralized granites from productive ones. The Ta-bearing samples, which are situated in the fertile field in the diagram, are those which have high Nb and Ta contents, elevated Ga content and the lowest Nb/Ta and Zr/Hf values.