Age, composition, and source of the Macururé Mafic Suite, Southern Borborema Province, Brazil

Abstract

Abstract The Capela, Dores, Aquidabã, Camará, Campo Grande, and Pedra Branca stocks constitute the Macururé Mafic Suite of the Sergipano Orogenic System, Southern Borborema Province. These bodies have elongated and tabular forms, which are concordant with the metasedimentary host rocks foliation. Most primitive terms are hornblendites, gabbros, and diorites, with minor monzonites, granodiorites, and granites. U-Pb SHRIMP zircon ages for Capela (631 ± 3 Ma), Aquidabã (636 ± 4 Ma) and Campo Grande (629 ± 9 Ma) stocks indicate the coeval emplacement of the intrusions. Geochemical data show that these rocks are metaluminous to slightly peraluminous, magnesian and have high-K calc-alkaline to shoshonitic affinities. Rare earth elements (REE) patterns are fractionated and multielement diagrams display depletions at Nb, Ta, and Ti, indicating subduction-related magmatism. Trace elements data suggest that the gabbros and diorites were generated by partial melting of an enriched subcontinental lithospheric mantle in the spinel stability field, which has probably been metasomatized by the interaction with sediments during previous subduction events. Field and petrographic evidence, associated with geochemical and geochronological data support that the magmas of the Macururé Mafic Suite were emplaced in early- to syn-collisional stage during the build-up of a continental arc in the Sergipano Orogenic System, at ca. 630 Ma.

Keywords

• Mafic Magmatism
• Continental Arc
• Ediacaran