U-Pb provenance fingerprints of metavolcanic-sedimentary successions of the Mineiro belt: Proxies for the continuity of plate tectonics through the Paleoproterozoic

Author(s)

Teixeira, W. ; Avila, C. A. ; Dussin, I. A. ; Bongiolo, E.

• Document type: Journal article
• Source: GEOSCIENCE FRONTIERS; v. 13, n. 5, p. 27-pg., 2022-08-26.

Abstract

We document new U-Pb detrital zircon LA-MC-ICP-MS data for seven metavolcanic-sedimentary succes-sions and metasedimentary sequences and reassess additional dates of five siliciclastic samples toward their tectonic significance in the context of the Mineiro belt, Southern Sao Francisco Craton. This belt rep-resents a crustal segment of the 2.47-2.00 Ga Minas Orogen, classically known by its Siderian and Rhyacian juvenile rocks with important implications in the Earth's geodynamics. The new and compiled detrital provenance constraints unravel the long-lived magmatic and sedimentary history of the studied basins, lasting ca. 230-220 Myr. The maximum depositional dates around 2.1 Ga reflect the renewed sed-iment budget with the subsequent metamorphic episode ca. 2.0 Ga. Most of the unmixed relative prob-ability diagrams are consistent with sourcing from the Siderian and Rhyacian arcs of the Mineiro belt, determining a detrital provenance change in time and space for the precursor basins. Alternative poten-tial sources could be the youngest rocks of the Mantiqueira and Juiz de Fora terranes that constitute the other segments of the Minas Orogen, given the age match. The overall detrital fingerprints determine the study basins resumed mainly in Rhyacian fore-arc and/or back-arc settings, i.e., akin to a subduction -related system that evolved to a collisional (foreland) environment. Few samples show fingerprints of pri-mary extensional settings, determined by major Archean detrital populations sourced from areas outside the Mineiro belt beside the Paleoproterozoic detritus. The working model considers the collage between the Mineiro belt and the ancient foreland around 2.10 Ga and eventual interaction with other crustal seg-ments of the Minas Orogen, generating the ca. 2.0 Ga metamorphism over the metasedimentary samples. The more complete isotopic repository in detrital and igneous zircon grains for the studied supracrustal successions and the associated rocks allows new insights into the Rhyacian-Orosirian dynamics of the Minas orogeny. In a broader perspective, the juvenile nature of the Mineiro belt reinforces the paradigm of uninterrupted continental growth during the Paleoproterozoic Earth.(c) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). (AU)