On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil
Autor(a) principal: | |
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Data de Publicação: | 2018 |
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Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Geology |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018000300631 |
Resumo: | ABSTRACT: Syn-orogenic Neoproterozoic granitic magmatism (ca. 630-600 Ma) in southern Brasília Orogen includes large batholiths of compositionally expanded high-K calc-alkaline granites (lato sensu) and small occurrences constituted by anatetic leuco-granites associated to the regional metamorphism. We present petrographic, mineralogical and geochemical data for a representative sample of the Bragança Paulista-type granite and estimates for magmatic crystallization conditions. The sample corresponds to a porphyritic hornblende-biotite monzogranite (CI ≈ 20) comprising perthitic microcline megacrysts within a medium-grained matrix with plagioclase (An 30 Ab 70 ), quartz, microcline and mafic minerals. The main mafic minerals are biotite (0.51 ≤ mg# ≤ 0.57) and Ca-amphibole (potassic-magnesio-hastingsite, 0.47 ≤ mg# ≤ 0.52), with similar volumes; accessory phases (ca. 2 vol.%) are Fe-Ti oxides (ferrian ilmenite, titanohematite, hematite and magnetite), allanite, apatite, zircon, titanite and sulphides. Our results indicate crystallization at 510 ± 60 MPa and temperatures from ca. 970ºC (close-to-liquidus) to 755 ± 45ºC (close-to-solidus), under oxidizing conditions, compatible with 0 ≤ ΔNNO ≤ +1. Estimated water and halogen fugacity ratios are ƒ H2O /ƒ HF ≥ 10 5.8 , 10 3.5 ≤ ƒ H2O /ƒ HCl ≤ 10 3.8 and ƒ HF /ƒ HCl ≤ 10 -2.2 . The obtained pressure, integrated with available regional geobarometric data, suggests a relative uplift rate about 0.2-0.3 (km/Ma) from the main regional metamorphism to the post-orogenic magmatism in the area. |
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Brazilian Journal of Geology |
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On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE BrazilIntensive crystallization parametershigh-K calc-alkaline granitesBragança Paulista-type granites, Neoproterozoic magmatism, Socorro-Guaxupé NappeABSTRACT: Syn-orogenic Neoproterozoic granitic magmatism (ca. 630-600 Ma) in southern Brasília Orogen includes large batholiths of compositionally expanded high-K calc-alkaline granites (lato sensu) and small occurrences constituted by anatetic leuco-granites associated to the regional metamorphism. We present petrographic, mineralogical and geochemical data for a representative sample of the Bragança Paulista-type granite and estimates for magmatic crystallization conditions. The sample corresponds to a porphyritic hornblende-biotite monzogranite (CI ≈ 20) comprising perthitic microcline megacrysts within a medium-grained matrix with plagioclase (An 30 Ab 70 ), quartz, microcline and mafic minerals. The main mafic minerals are biotite (0.51 ≤ mg# ≤ 0.57) and Ca-amphibole (potassic-magnesio-hastingsite, 0.47 ≤ mg# ≤ 0.52), with similar volumes; accessory phases (ca. 2 vol.%) are Fe-Ti oxides (ferrian ilmenite, titanohematite, hematite and magnetite), allanite, apatite, zircon, titanite and sulphides. Our results indicate crystallization at 510 ± 60 MPa and temperatures from ca. 970ºC (close-to-liquidus) to 755 ± 45ºC (close-to-solidus), under oxidizing conditions, compatible with 0 ≤ ΔNNO ≤ +1. Estimated water and halogen fugacity ratios are ƒ H2O /ƒ HF ≥ 10 5.8 , 10 3.5 ≤ ƒ H2O /ƒ HCl ≤ 10 3.8 and ƒ HF /ƒ HCl ≤ 10 -2.2 . The obtained pressure, integrated with available regional geobarometric data, suggests a relative uplift rate about 0.2-0.3 (km/Ma) from the main regional metamorphism to the post-orogenic magmatism in the area.Sociedade Brasileira de Geologia2018-07-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018000300631Brazilian Journal of Geology v.48 n.3 2018reponame:Brazilian Journal of Geologyinstname:Sociedade Brasileira de Geologia (SBGEO)instacron:SBGEO10.1590/2317-4889201820180033info:eu-repo/semantics/openAccessSalazar-Naranjo,Andrés FabiánVlach,Silvio Roberto Fariaseng2018-10-03T00:00:00Zoai:scielo:S2317-48892018000300631Revistahttp://bjg.siteoficial.ws/index.htmhttps://old.scielo.br/oai/scielo-oai.phpsbgsede@sbgeo.org.br||claudio.riccomini@gmail.com2317-46922317-4692opendoar:2018-10-03T00:00Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO)false |
dc.title.none.fl_str_mv |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
title |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
spellingShingle |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil Salazar-Naranjo,Andrés Fabián Intensive crystallization parameters high-K calc-alkaline granites Bragança Paulista-type granites, Neoproterozoic magmatism, Socorro-Guaxupé Nappe |
title_short |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
title_full |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
title_fullStr |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
title_full_unstemmed |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
title_sort |
On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil |
author |
Salazar-Naranjo,Andrés Fabián |
author_facet |
Salazar-Naranjo,Andrés Fabián Vlach,Silvio Roberto Farias |
author_role |
author |
author2 |
Vlach,Silvio Roberto Farias |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Salazar-Naranjo,Andrés Fabián Vlach,Silvio Roberto Farias |
dc.subject.por.fl_str_mv |
Intensive crystallization parameters high-K calc-alkaline granites Bragança Paulista-type granites, Neoproterozoic magmatism, Socorro-Guaxupé Nappe |
topic |
Intensive crystallization parameters high-K calc-alkaline granites Bragança Paulista-type granites, Neoproterozoic magmatism, Socorro-Guaxupé Nappe |
description |
ABSTRACT: Syn-orogenic Neoproterozoic granitic magmatism (ca. 630-600 Ma) in southern Brasília Orogen includes large batholiths of compositionally expanded high-K calc-alkaline granites (lato sensu) and small occurrences constituted by anatetic leuco-granites associated to the regional metamorphism. We present petrographic, mineralogical and geochemical data for a representative sample of the Bragança Paulista-type granite and estimates for magmatic crystallization conditions. The sample corresponds to a porphyritic hornblende-biotite monzogranite (CI ≈ 20) comprising perthitic microcline megacrysts within a medium-grained matrix with plagioclase (An 30 Ab 70 ), quartz, microcline and mafic minerals. The main mafic minerals are biotite (0.51 ≤ mg# ≤ 0.57) and Ca-amphibole (potassic-magnesio-hastingsite, 0.47 ≤ mg# ≤ 0.52), with similar volumes; accessory phases (ca. 2 vol.%) are Fe-Ti oxides (ferrian ilmenite, titanohematite, hematite and magnetite), allanite, apatite, zircon, titanite and sulphides. Our results indicate crystallization at 510 ± 60 MPa and temperatures from ca. 970ºC (close-to-liquidus) to 755 ± 45ºC (close-to-solidus), under oxidizing conditions, compatible with 0 ≤ ΔNNO ≤ +1. Estimated water and halogen fugacity ratios are ƒ H2O /ƒ HF ≥ 10 5.8 , 10 3.5 ≤ ƒ H2O /ƒ HCl ≤ 10 3.8 and ƒ HF /ƒ HCl ≤ 10 -2.2 . The obtained pressure, integrated with available regional geobarometric data, suggests a relative uplift rate about 0.2-0.3 (km/Ma) from the main regional metamorphism to the post-orogenic magmatism in the area. |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-07-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018000300631 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2317-48892018000300631 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/2317-4889201820180033 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
publisher.none.fl_str_mv |
Sociedade Brasileira de Geologia |
dc.source.none.fl_str_mv |
Brazilian Journal of Geology v.48 n.3 2018 reponame:Brazilian Journal of Geology instname:Sociedade Brasileira de Geologia (SBGEO) instacron:SBGEO |
instname_str |
Sociedade Brasileira de Geologia (SBGEO) |
instacron_str |
SBGEO |
institution |
SBGEO |
reponame_str |
Brazilian Journal of Geology |
collection |
Brazilian Journal of Geology |
repository.name.fl_str_mv |
Brazilian Journal of Geology - Sociedade Brasileira de Geologia (SBGEO) |
repository.mail.fl_str_mv |
sbgsede@sbgeo.org.br||claudio.riccomini@gmail.com |
_version_ |
1752122398898913280 |