New U-Pb SHRIMP-II zircon intrusion ages of the Cana Brava and Barro Alto layered complexes, central Brazil: constraints on the genesis and evolution of the Tonian Goias Stratiform Complex

Author(s)

Giovanardi, Tommaso ; Girardi, Vicente A. V. ; Correia, Ciro T. ; Tassinari, Colombo C. G. ; Sato, Kei ; Cipriani, Anna ; Mazzucchelli, Maurizio

• Document type: Journal article
• Source: LITHOS; v. 282, p. 339-357, JUN 2017.
• Web of Science Citations: 2

Abstract

The Cana Brava, Niquelandia and Barro Alto complexes (Goias, central Brazil) are three of the largest maficultramafic layered complexes in the world and their origin has been a matter of debate for several decades. One hypothesis suggests that Niquelandia and Barro Alto were both formed by two distinct igneous events at 13 Ga and at 790 Ma and were later overlapped during tectonic exhumation at 650 Ma; according to this reconstruction Cana Brava belongs to the youngest intrusion at 790 Ma. A second hypothesis suggests that the three complexes formed during the same event. Here we provide new U-Pb SHRIMP-II zircon ages for the Cana Brava and Barro Alto complexes, constraining their intrusion age to the Neoproterozoic (between 770 and 800 Ma), coeval with Niquelandia. A review of new and literature ages indicate that these complexes formed during a single igneous event and were not modified by regional metamorphism. We propose that the complexes represent fragments of the larger Tonian Goias Stratiform Complex, which was likely part of a back-arc environment connected to the formation of the Goias Magmatic Arc at about 790 Ma, later disrupted and accreted to the sao Francisco craton. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/19519-6 - Geochemistry and modelling of basic intrusions in the Cana Brava and Niquelândia Mafic-Ultramafic Complexes.
• Grantee: Tommaso Giovanardi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral