Rhyacian (2.23–2.20 Ga) juvenile accretion in the southern São Francisco craton,Brazil: Geochemical and isotopic evidence from the Serrinha magmatic suite,Mineiro belt |
| |
| Authors: | Ciro Alexandre Ávila Wilson Teixeira Umberto Giuseppe Cordani Candido Augusto Veloso Moura Ronaldo Mello Pereira |
| |
| Institution: | 1. Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, 20940-040 São Cristóvão, Rio de Janeiro, RJ, Brazil;2. Instituto de Geociências, Universidade de São Paulo, Rua do Lago 562, 05508-080 Butantã, São Paulo, SP, Brazil;3. Departamento de Petrologia e Geoquímica, Universidade Federal do Pará, Rua Augusto Correa 1, 66075-110 Guamá, Belém, PA, Brazil;4. Departamento de Geologia Aplicada, Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, Sala 2019A, 20540-900 Maracanã, Rio de Janeiro, RJ, Brazil;1. Ludwig-Maximilians Univ., Dept. of Earth and Environmental Sc., Munich, Germany;2. IGc-GMG-USP, São Paulo, Brazil;3. UFRJ, Inst. de Geociências, Dept. de Geologia, RJ, Brazil;4. UFMG–CPMTC, MG, Brazil;5. UERJ, Dept. de Geologia, RJ, Brazil;6. UNB, Dept. Mineralogia e Petrologia, Inst. de Geociências, D.F., Brazil;1. Programa de Pós–graduação em Geologia – PPGL, Universidade Federal do Rio de Janeiro – UFRJ, CEP 21941–916, Rio de Janeiro, Brazil;2. Instituto de Geociências, Universidade Federal do Rio de Janeiro – UFRJ, CEP 21941–916, Rio de Janeiro, Brazil;3. Museu Nacional, Universidade Federal do Rio de Janeiro – UFRJ, Rio de Janeiro, Brazil;1. Instituto de Geociências, Universidade de São Paulo, Rua do Lago, 562, 05508-080 São Paulo, SP, Brazil;2. Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil;3. FAPESP, Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil;4. Instituto de Geociências, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil;5. Centre for Exploration Targeting, University of Western Australia, Australia;6. Graduate Program, Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil;1. Departamento de Geologia, Universidade Federal de Ouro Preto, Morro do Cruzeiro, CEP 35400-000 Ouro Preto, Brazil;2. Université Paris-Sud, Laboratoire IDES, UMR8148, F-91405 Orsay Cedex, France;3. Université Cergy-Pontoise, IUFM, F-95000 Cergy-Pontoise, France;4. GEOTOP Université du Québec à Montréal, P.O. Box 8888, Station Centre Ville, Montréal, Québec H3C 3P8, Canada;1. Programa de Pós-graduação em Geologia (PPGL), Instituto de Geociências, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil;2. Instituto de Geociências, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil;3. Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil;4. Department of Geology and Natural Resources, Institute of Geosciences, University of Campinas – UNICAMP, Campinas, SP, Brazil;5. Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil;6. Petrobras, UO-RIO/ATP-RO/RES, Rio de Janeiro, RJ, Brazil;7. Petrobras, E&P-EXP/AFOE/ADGP, Rio de Janeiro, RJ, Brazil |
| |
| Abstract: | The Serrinha magmatic suite (Mineiro belt) crops out in the southern edge of the São Francisco craton, comprising the Brito quartz-diorite, Brumado de Cima and Brumado de Baixo granodiorites, granophyres and felsic sub-volcanic and volcanic rocks, part of which intruded into the Nazareno greenstone belt. The suite rocks have petrographic features that are consistent with magma supercooling due to the low water content combined with volatile loss, leading to crystallization of quartz and alkaline feldspar at the rims of plagioclase phenocrysts (granophyric intergrowth). The investigated rocks are sub-alkaline, calc-alkaline and show low content in rare earth elements. The U–Pb zircon crystallization ages for the Brumado de Cima granodiorite 2227 ± 22 (23) Ma] and a coeval granophyre 2211 ± 22 (23) Ma], coupled with available single-zircon Pb evaporation ages for the Brito and Brumado de Baixo plutons, are significantly older than the “Minas orogeny” (ca. 2100–2050 Ga) of Quadrilátero Ferrífero area, eastward from the Serrinha suite. Our data establish an early Rhyacian event tectonically linked with the evolution of the Mineiro belt. The bulk Nd isotopic signature low negative to positive εNd(t) values] of the Serrinha samples are consistent with the important role of Paleoproterozoic mantle components in the magma genesis. The integrated geologic, geochemical and isotopic information suggests that Paleoproterozoic evolution of the Mineiro belt initiated in a passive continental margin basin with deposition of the Minas Supergroup at ca. 2500 Ma. This stage was succeeded by outboard rupture of the oceanic lithosphere with development and coalescence of progressively younger magmatic arcs during Rhyacian time. One of the earliest arcs formed the Serrinha suite. The tectonic collage of the Serrinha and Ritápolis (2190–2120 Ma) arcs produced the NE–SW Lenheiro shear zone, resulting in mylonitization and recrystallization of both the granitoid intrusions and host rocks. As a matter of fact juxtaposition of distinct magmatic units in age and origin took place along the Lenheiros structure in this sector of the Mineiro belt. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
