Neoarchean and Rhyacian TTG-Sanukitoid suites in the southern São Francisco Paleocontinent, Brazil: Evidence for diachronous change towards modern tectonics
| Autor: | Samuel Moreira Bersan, Mike Fowler, Henrique Bruno, Hugo Moreira, Claudio de Morisson Valeriano, Craig Storey, Rob Strachan, Luiz Guilherme do Eirado Silva, Ivo Dussin, Monica Heilbron, Julio Cesar Horta de Almeida, Carla Cristine Aguiar Neto, Miguel Tupinambá, Vitalino Elizeu |
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| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Archean Geochemistry Diachronous TTG-Sanukitoid transition Metamorphism Geodynamics 010502 geochemistry & geophysics 01 natural sciences Siderian Mantiqueira complex geodynamics 0105 earth and related environmental sciences Terrane Sanukitoid Mantiqueira Complex Orosirian lcsh:QE1-996.5 Paleoproterozoic Granulite lcsh:Geology paleoproterozoic diachronous TTG-sanukitoid transition Rhyacian Earth Sciences General Earth and Planetary Sciences High Ba–Sr granitoids high Ba-Sr granitoids Geology |
| Zdroj: | Bruno, H, Elizeu, V, Heilbron, M, De Morisson Valeriano, C, Strachan, R, Fowler, M, Bersan, S, Moreira, H, Dussin, I, Guilherme Do Eirado Silva, L, Tupinambá, M, Almeida, J, Neto, C & Storey, C 2020, ' Neoarchean and Rhyacian TTG-Sanukitoid suites in the southern São Francisco Paleocontinent, Brazil: evidence for diachronous change towards modern tectonics ', Geoscience Frontiers . https://doi.org/10.1016/j.gsf.2020.01.015 Geoscience Frontiers, Vol 11, Iss 5, Pp 1763-1787 (2020) |
| ISSN: | 1674-9871 |
| DOI: | 10.1016/j.gsf.2020.01.015 |
| Popis: | The southern portion of the Sao Francisco Palaeocontinent in Brazil is denoted by Archean nuclei and Paleoproterozoic magmatic arcs that were amalgamated during Siderian to Orosirian orogenic processes (ca. 2.4–2.1 Ga). New isotopic U–Pb in zircon and Sm–Nd whole rock combined with major and trace element composition analyses constrain the crystallization history of the Neoarchean Piedade block (at ca. 2.6 Ga) and the Paleoproterozoic Mantiqueira Complex (ca. 2.1–1.9 Ga). These therefore display quite different magmatic histories prior to their amalgamation at ca. 2.05 Ga. Sm–Nd and Rb–Sr isotopes imply a mixed mantle-crustal origin for the samples in both units. A complete Palaeoproterozoic orogenic cycle, from subduction to collision and collapse, is recorded in the Piedade Block and the Mantiqueira Complex. Rhyacian to Orosirian subduction processes (ca. 2.2–2.1 Ga) led to the generation of coeval (ca. 2.16 Ga) TTG suites and sanukitoids, followed by late (2.10–2.02 Ga) high-K granitoids that mark the collisional stage. The collisional accretion of the Mantiqueira Complex against the Piedade Block at 2.08–2.04 Ga is also recorded by granulite facies metamorphism in the latter terrane, along the Ponte Nova suture zone. The collisional stage was closely followed by the emplacement of within-plate tholeiites at ca. 2.04 Ga and by alkaline rocks (syenites and enriched basic rocks) at ca. 1.98 Ga, marking the transition to an extensional tectonic regime. The discovery of two episodes of TTG and sanukitoid magmatism, one during the Neoarchean in the Piedade Complex and another during the Rhyacian in the Mantiqueira Complex, indicates that the onset of subduction-related melting of metasomatized mantle was not restricted to Neoarchean times, as generally believed, but persisted much later into the Paleoproterozoic. |
| Databáze: | OpenAIRE |
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