Trace element tectonic discrimination of granitoids: inspiration from big data analytics

Abstract

ABSTRACTThe tectonic environment of granitoids has always been a concern of the academic community. The Nb vs. Y and Rb vs. Nb+Y diagrams have had a substantial impact. The present work uses more than 110,000 granitoid samples (SiO2 ≥ 56%) from the globally shared database to discuss the validity and also explain why these diagrams used for discrimination between the different tectonic settings of granitoid rocks. The amount of data from the spreading center is sparse and the data are highly scattered and so, the present study focuses mainly on granites from the ocean islands and convergent margins tectonic environments. On the TAS diagram most of the ocean island data are alkaline series and trachy-basalt series, and some are bimodal. In contrast, the granitoids on the convergent margin are mainly sub-alkaline. This work shows that the tectonic discrimination diagrams of granitoids remain valid, and only the boundaries need to be slightly adjusted.

Keywords

• Spreading center
• Ocean Island
• Apenninic-Maghrebides chain
• tectonic discrimination
• granitoids
• convergent margin