Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex
ABSTRACT: The Itatiaia Alkaline Massif comprises some of the largest meso-cenozoic alkaline igneous occurrences in Brazil, covering over 215 km2 between the states of Minas Gerais and Rio de Janeiro. It appears as an elongated, 30-km long and 4.5-11.5-km wide SE-NW-trending body emplaced along accom...
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Geologia
2018-05-01
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| Series: | Brazilian Journal of Geology |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018005004101&lng=en&tlng=en |
| _version_ | 1819073888928137216 |
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| author | Pedro Augusto da Silva Rosa Excelso Ruberti |
| author_facet | Pedro Augusto da Silva Rosa Excelso Ruberti |
| author_sort | Pedro Augusto da Silva Rosa |
| collection | DOAJ |
| description | ABSTRACT: The Itatiaia Alkaline Massif comprises some of the largest meso-cenozoic alkaline igneous occurrences in Brazil, covering over 215 km2 between the states of Minas Gerais and Rio de Janeiro. It appears as an elongated, 30-km long and 4.5-11.5-km wide SE-NW-trending body emplaced along accommodation zones of the Continental Rift of Southern Brazil, intruding metapelites, orthogneiss and granites of the Brasília and Ribeira fold belts. New data and geological mapping suggest that the massif evolved from a migratory magmatic center manifested as ring structures and successive moon-shaped intrusions from SE to NW in three sectors of distinct lithological and geomorphological characteristics: Southeastern, Central and Northwestern. The lithological variants in the three sectors present themselves as discrete intrusive bodies, comprising feldspathoid-bearing and quartz-bearing syenites, porphyritic to breccioid trachytes, granite, monzonite, gabbro and trachybasalt, which can be grouped into 21 units. These rocks occur in five petrographical sets: plagioclase-free nepheline syenites, plagioclase-bearing nepheline syenite and pulaskites, nordmarkite-granite series, anti-rapakivi associations and basic rocks. Sin- to tardi-plutonic dykes of nephelinites, phonolites, trachytes and rhyolites are also present. |
| first_indexed | 2024-12-21T18:00:47Z |
| format | Article |
| id | doaj.art-f5d1dcd8f7564326bb6ef979d30d91e7 |
| institution | Directory Open Access Journal |
| issn | 2317-4692 |
| language | English |
| last_indexed | 2024-12-21T18:00:47Z |
| publishDate | 2018-05-01 |
| publisher | Sociedade Brasileira de Geologia |
| record_format | Article |
| series | Brazilian Journal of Geology |
| spelling | doaj.art-f5d1dcd8f7564326bb6ef979d30d91e72022-12-21T18:55:04ZengSociedade Brasileira de GeologiaBrazilian Journal of Geology2317-46922018-05-01010.1590/2317-4889201820170092S2317-48892018005004101Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring ComplexPedro Augusto da Silva RosaExcelso RubertiABSTRACT: The Itatiaia Alkaline Massif comprises some of the largest meso-cenozoic alkaline igneous occurrences in Brazil, covering over 215 km2 between the states of Minas Gerais and Rio de Janeiro. It appears as an elongated, 30-km long and 4.5-11.5-km wide SE-NW-trending body emplaced along accommodation zones of the Continental Rift of Southern Brazil, intruding metapelites, orthogneiss and granites of the Brasília and Ribeira fold belts. New data and geological mapping suggest that the massif evolved from a migratory magmatic center manifested as ring structures and successive moon-shaped intrusions from SE to NW in three sectors of distinct lithological and geomorphological characteristics: Southeastern, Central and Northwestern. The lithological variants in the three sectors present themselves as discrete intrusive bodies, comprising feldspathoid-bearing and quartz-bearing syenites, porphyritic to breccioid trachytes, granite, monzonite, gabbro and trachybasalt, which can be grouped into 21 units. These rocks occur in five petrographical sets: plagioclase-free nepheline syenites, plagioclase-bearing nepheline syenite and pulaskites, nordmarkite-granite series, anti-rapakivi associations and basic rocks. Sin- to tardi-plutonic dykes of nephelinites, phonolites, trachytes and rhyolites are also present.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018005004101&lng=en&tlng=enAlkaline rocksNepheline syeniteQuartz syeniteGeological mappingItatiaia |
| spellingShingle | Pedro Augusto da Silva Rosa Excelso Ruberti Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex Brazilian Journal of Geology Alkaline rocks Nepheline syenite Quartz syenite Geological mapping Itatiaia |
| title | Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex |
| title_full | Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex |
| title_fullStr | Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex |
| title_full_unstemmed | Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex |
| title_short | Nepheline syenites to syenites and granitic rocks of the Itatiaia Alkaline Massif, Southeastern Brazil: new geological insights into a migratory ring Complex |
| title_sort | nepheline syenites to syenites and granitic rocks of the itatiaia alkaline massif southeastern brazil new geological insights into a migratory ring complex |
| topic | Alkaline rocks Nepheline syenite Quartz syenite Geological mapping Itatiaia |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018005004101&lng=en&tlng=en |
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