U-Pb (LA-ICPMS) zircon ages and Nd isotopes for granitoids of the Tamboril-Santa Quitéria Complex, Ceará Central Domain: implication for neoproterozoic syncollisional magmatism in north Borborema Province

Abstract

The Tamboril-Santa Quitéria Complex (TSQC) is one of the largest Neoproterozoic plutonic manifestations in the northBorborema Province (NE Brazil). It represents an anatectic/igneous association characterized by a number of magmaticpulses that occurred in the 650-610 Ma interval. In this paper, we present U-Pb (LA-MC-ICP-MS) zircon ages and Ndisotopes for quartz monzonites and quartz diorites of the southern part of TSQC. The quartz monzonites belong to a hybridgranitoid association, including monzonites, syenites and quartz syenites, all with abundant mafic magmatic enclaves.A quartz monzonite sample yielded a U-Pb zircon age of 634 ± 10 Ma and a TDM age of 2.69 Ga. The quartz diorites aremuch more homogeneous in composition and yielded a U-Pb zircon age of 618 ± 23 Ma and a TDM age of 2.19 Ga. Thepresence of coeval mantle-derived magmatism and diatexites (crustal anatexis) post-dating high-pressure metamorphism(ca. 650 Ma), and together with high-temperature metamorphism (ca. 630-610 Ma), suggests that this large magmatic manifestationevolved in a collisional setting, probably related to slab breakoff during the Western Gondwana amalgamation.

Keywords

• Borborema Province
• Neoproterozoic magmatism
• Continental collision.