Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil
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| Natura: | Artículo científico |
| Lingua: | en |
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Academia Brasileira de Ciências
2006
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| _version_ | 1876472720909139968 |
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| author | Renato J. Leite |
| author_facet | Renato J. Leite |
| contents | Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil Renato J. Leite Valdecir de Assis Janasi Lucelene Martins Multidisciplinaria (Ciencias Naturales y Exactas) Sr calc granite alkaline peraluminous The Piedade Granite (∼600 Ma) was emplaced shortly after the main phase of granite magmatism in the AgudosGrandes batholith, Apiaí-Guaxupé Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyriticgranites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite MBmg unit) andcore (metaluminous titanite-bearing biotite monzogranite BmgT unit) and felsic pink inequigranular granite(Bmg unit) between them. Bmg has high LaN/YbN (up to 100), Th/U (>10) and low Rb, Nb and Ta, andcan be a crustal melt derived from deep-seated sources with residual garnet and biotite. The core BmgT unitderived from oxidized magmas with high Mg# (∼45), Ba and Sr, fractionated REE patterns (LaN/YbN= 45),87Sr/86Sr(t)∼ 0.710, εNd(t) ∼ 12 to 14, interpreted as being high-K calc-alkaline magmas contaminatedwith metasedimentary rocks that had upper-crust signature (high U, Cs, Ta). The mafic-rich peraluminousgranites show a more evolved isotope signature (87Sr/86Sr(t) = 0.713 0.714; εNd(t)= 14 to 16), similarto Bmg, and Mg# and incompatible trace-element concentrations intermediate between Bmg and BmgT. Amodel is presented in whichMBmgis envisaged as the product of contamination between amafic mineral-richmagma consanguineous with BmgT and pure crustal melts akin to Bmg. 2006 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32778213 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.78 |
| format | Artículo científico |
| id | redalyc_32778213 |
| institution | Redalyc |
| language | en |
| publishDate | 2006 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil Renato J. Leite Multidisciplinaria (Ciencias Naturales y Exactas) Sr calc granite alkaline peraluminous Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil Renato J. Leite Valdecir de Assis Janasi Lucelene Martins Multidisciplinaria (Ciencias Naturales y Exactas) Sr calc granite alkaline peraluminous The Piedade Granite (∼600 Ma) was emplaced shortly after the main phase of granite magmatism in the AgudosGrandes batholith, Apiaí-Guaxupé Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyriticgranites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite MBmg unit) andcore (metaluminous titanite-bearing biotite monzogranite BmgT unit) and felsic pink inequigranular granite(Bmg unit) between them. Bmg has high LaN/YbN (up to 100), Th/U (>10) and low Rb, Nb and Ta, andcan be a crustal melt derived from deep-seated sources with residual garnet and biotite. The core BmgT unitderived from oxidized magmas with high Mg# (∼45), Ba and Sr, fractionated REE patterns (LaN/YbN= 45),87Sr/86Sr(t)∼ 0.710, εNd(t) ∼ 12 to 14, interpreted as being high-K calc-alkaline magmas contaminatedwith metasedimentary rocks that had upper-crust signature (high U, Cs, Ta). The mafic-rich peraluminousgranites show a more evolved isotope signature (87Sr/86Sr(t) = 0.713 0.714; εNd(t)= 14 to 16), similarto Bmg, and Mg# and incompatible trace-element concentrations intermediate between Bmg and BmgT. Amodel is presented in whichMBmgis envisaged as the product of contamination between amafic mineral-richmagma consanguineous with BmgT and pure crustal melts akin to Bmg. 2006 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32778213 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.78 |
| title | Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) Sr calc granite alkaline peraluminous |
| url | https://www.redalyc.org/articulo.oa?id=32778213 |