Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature
This article presents geochemical characteristics of the alkaline rocks of Rio Bonito intrusive complex, State of Rio de Janeiro, Brazil, which is constituted mainly by nepheline syenite. The fractional crystallisation of this magma decreases K2O/(Na2O + K2O) and increases (Na + K)/Al. The TiO2, Fe2...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Universidade de São Paulo
2020-12-01
|
| Series: | Geologia USP. Série Científica |
| Subjects: | |
| Online Access: | https://www.revistas.usp.br/guspsc/article/view/180297 |
| _version_ | 1818897597083942912 |
|---|---|
| author | Daniel Adelino da Silva Akihisa Motoki Anderson Costa dos Santos Julio Mendes Fred Jourdan Mauro César Geraldes Cristiano de Carvalho Lana |
| author_facet | Daniel Adelino da Silva Akihisa Motoki Anderson Costa dos Santos Julio Mendes Fred Jourdan Mauro César Geraldes Cristiano de Carvalho Lana |
| author_sort | Daniel Adelino da Silva |
| collection | DOAJ |
| description | This article presents geochemical characteristics of the alkaline rocks of Rio Bonito intrusive complex, State of Rio de Janeiro, Brazil, which is constituted mainly by nepheline syenite. The fractional crystallisation of this magma decreases K2O/(Na2O + K2O) and increases (Na + K)/Al. The TiO2, Fe2O3*, MgO, CaO, and P2O5 contents indicate fractionation of titanite, ilmenite, and clinopyroxene or amphibole. The total rare earth elements (REEs) are high, and the REE pattern is linear with negative gradient. The nepheline syenite aplite has low REEs, concave REE pattern, and positive Eu anomaly. The ultrabasic and basic mela-nepheline syenite samples have total REEs and light REEs higher than the felsic alkaline rocks. Therefore, the nepheline syenite magma is not derived directly from the alkaline ultrabasic magma. Laser-spot step‑heating 40Ar/39Ar ages for biotite and amphibole are 65.03 ± 0.70 and 65.03 ± 0.46. U-Pb ages LA-ICP-MS for two samples are 65.49 ± 0.30 and 65.18 ± 0.30. Values of εHf are negative for both samples, indicating an important crustal component in the evolution of Rio Bonito. |
| first_indexed | 2024-12-19T19:18:42Z |
| format | Article |
| id | doaj.art-1a1e88ba5f47481c8945cbad66e8234e |
| institution | Directory Open Access Journal |
| issn | 2316-9095 |
| language | English |
| last_indexed | 2024-12-19T19:18:42Z |
| publishDate | 2020-12-01 |
| publisher | Universidade de São Paulo |
| record_format | Article |
| series | Geologia USP. Série Científica |
| spelling | doaj.art-1a1e88ba5f47481c8945cbad66e8234e2022-12-21T20:09:04ZengUniversidade de São PauloGeologia USP. Série Científica2316-90952020-12-01204Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signatureDaniel Adelino da Silva0Akihisa Motoki 1Anderson Costa dos Santos2Julio Mendes3Fred Jourdan4Mauro César Geraldes5Cristiano de Carvalho Lana6Universidade do Estado do Rio de Janeiro. Departamento de Mineralogia e Petrologia Ígnea.Universidade do Estado do Rio de Janeiro. Departamento de Mineralogia e Petrologia Ígnea.Universidade do Estado do Rio de Janeiro. Departamento de Mineralogia e Petrologia Ígnea.Universidade Federal do Rio de Janeiro. Instituto de Geociências.University of Technology. Department of Applied Geology & JdL CentreUniversidade do Estado do Rio de Janeiro. Departamento de Mineralogia e Petrologia Ígnea.Universidade Federal de Ouro Preto.This article presents geochemical characteristics of the alkaline rocks of Rio Bonito intrusive complex, State of Rio de Janeiro, Brazil, which is constituted mainly by nepheline syenite. The fractional crystallisation of this magma decreases K2O/(Na2O + K2O) and increases (Na + K)/Al. The TiO2, Fe2O3*, MgO, CaO, and P2O5 contents indicate fractionation of titanite, ilmenite, and clinopyroxene or amphibole. The total rare earth elements (REEs) are high, and the REE pattern is linear with negative gradient. The nepheline syenite aplite has low REEs, concave REE pattern, and positive Eu anomaly. The ultrabasic and basic mela-nepheline syenite samples have total REEs and light REEs higher than the felsic alkaline rocks. Therefore, the nepheline syenite magma is not derived directly from the alkaline ultrabasic magma. Laser-spot step‑heating 40Ar/39Ar ages for biotite and amphibole are 65.03 ± 0.70 and 65.03 ± 0.46. U-Pb ages LA-ICP-MS for two samples are 65.49 ± 0.30 and 65.18 ± 0.30. Values of εHf are negative for both samples, indicating an important crustal component in the evolution of Rio Bonito.https://www.revistas.usp.br/guspsc/article/view/180297Nepheline syeniteRio BonitoFractional crystallisationCrustal assimilation40Ar/39Ar and U-Pb dating |
| spellingShingle | Daniel Adelino da Silva Akihisa Motoki Anderson Costa dos Santos Julio Mendes Fred Jourdan Mauro César Geraldes Cristiano de Carvalho Lana Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature Geologia USP. Série Científica Nepheline syenite Rio Bonito Fractional crystallisation Crustal assimilation 40Ar/39Ar and U-Pb dating |
| title | Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature |
| title_full | Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature |
| title_fullStr | Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature |
| title_full_unstemmed | Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature |
| title_short | Multiple processes of geochemical evolution for the alkaline rocks of Rio Bonito intrusive complex, Rio de Janeiro State, Brazil: 40Ar/39Ar and U-Pb ages and Lu-Hf isotopes on zircon and constraints on crustal signature |
| title_sort | multiple processes of geochemical evolution for the alkaline rocks of rio bonito intrusive complex rio de janeiro state brazil 40ar 39ar and u pb ages and lu hf isotopes on zircon and constraints on crustal signature |
| topic | Nepheline syenite Rio Bonito Fractional crystallisation Crustal assimilation 40Ar/39Ar and U-Pb dating |
| url | https://www.revistas.usp.br/guspsc/article/view/180297 |
| work_keys_str_mv | AT danieladelinodasilva multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT akihisamotoki multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT andersoncostadossantos multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT juliomendes multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT fredjourdan multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT maurocesargeraldes multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature AT cristianodecarvalholana multipleprocessesofgeochemicalevolutionforthealkalinerocksofriobonitointrusivecomplexriodejaneirostatebrazil40ar39arandupbagesandluhfisotopesonzirconandconstraintsoncrustalsignature |