首页 | 本学科首页   官方微博 | 高级检索  
     检索      


U-Pb provenance fingerprints of metavolcanic-sedimentary successions of the Mineiro belt: Proxies for the continuity of plate tectonics through the Paleoproterozoic
Institution:1. Instituto de Geociências, Universidade de São Paulo, Brazil;2. Museu Nacional, Universidade Federal do Rio de Janeiro, Brazil;3. Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Brazil;4. Programa de Pós-graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Brazil
Abstract:We document new U-Pb detrital zircon LA-MC-ICP-MS data for seven metavolcanic-sedimentary successions and metasedimentary sequences and reassess additional dates of five siliciclastic samples toward their tectonic significance in the context of the Mineiro belt, Southern São Francisco Craton. This belt represents 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 sediment budget with the subsequent metamorphic episode ca. 2.0 Ga. Most of the unmixed relative probability 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 potential 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 primary 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 segments 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.
Keywords:Paleoproterozoic  São Francisco Craton  Detrital zircon geochronology  Metavolcanic-sedimentary basin
本文献已被 ScienceDirect 等数据库收录!
点击此处可从《地学前缘(英文版)》浏览原始摘要信息
点击此处可从《地学前缘(英文版)》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号