Tectonic setting of basic rocks of Borborema province, Brazil, inferred from multi-dimensional discrimination diagrams

Abstract

Fifteen multi-dimensional diagrams [1-3] for basic and ultrabasic rocks, based on log-ratio transformations, were used to decipher tectonic setting for two case studies of Borborema province, NE Brazil.The applications of these diagrams indicated the following results: (1) a mid-ocean ridge setting for ForquilhaEclogite Zone during the Mesoproterozoic; (2) a transitional island arc to mid- ocean ridge setting for Algodões during the Paleoproterozoic.Our interpretations of main result for basic-ultrabasic magmas, along with the original authors' findings, were generally consistent.