The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny

Two regional thrust-sheets of Neoproterozoic metasedimentary rocks occur in the Southern Brasilia Belt, northwest Minas Gerais. The lower one comprises the Vazante Group, that is formed in the studied area, from base to top, by the Serra do Garrote (metapelites interlayered with carbonaceous phyllit...

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Autores principales: De Oliveira Carvalho, M., De Morisson Valeriano, C., González, P.A.A., Oliveira, G.D., Impiccini, A.
Formato: JOUR
Materias:
Neoproterozoic
Thrust-fold Belt
X-Ray Diffraction
Zinc-Lead
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_23174889_v46_n4_p567_DeOliveiraCarvalho
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_23174889_v46_n4_p567_DeOliveiraCarvalho2023-10-03T16:40:57Z The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny De Oliveira Carvalho, M. De Morisson Valeriano, C. González, P.A.A. Oliveira, G.D. Impiccini, A. Neoproterozoic Thrust-fold Belt X-Ray Diffraction Zinc-Lead Two regional thrust-sheets of Neoproterozoic metasedimentary rocks occur in the Southern Brasilia Belt, northwest Minas Gerais. The lower one comprises the Vazante Group, that is formed in the studied area, from base to top, by the Serra do Garrote (metapelites interlayered with carbonaceous phyllite), Serra do Poco Verde (beige to pink stromatolitic metadolomite with interlayered greenish slates), Morro do Calcario (gray stromatolitic metadolomite interlayered with gray slates) and Serra da Lapa (phyllite with dolarenitic lenses interlayered with slates) formations. The upper thrust sheet consists of the Canastra Group (Paracatu formation): laminated sericite phyllites and carbonaceous phyllites interlayered with quartzite. The Braziliano orogeny resulted in four phases of contractional deformation, associated with low-grade metamorphism. The first two (D1 and D2) are ductile, while the third and fourth ones (D3 and D4) are brittle-ductile. D1 developed a slaty S1 cleavage subparallel to the primary layering, with shallow to steep dips to NW. D2 developed a crenulation cleavage (S2) that dips moderately to NW and is associated with tight to isoclinal folds. D3 and D4 phases developed crenulations and open folds and kink bands. S3 dips steeply to NW, while S4 has moderate to steep dips to NE and SW. White mica crystallinity (Kubler index) measurements in metapelites indicate that both the Canastra and Vazante groups reached anchizone/epizone conditions, and metamorphic discontinuities along thrusts indicate that the peak of metamorphism is pre or syn-thrusting. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_23174889_v46_n4_p567_DeOliveiraCarvalho
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Neoproterozoic
Thrust-fold Belt
X-Ray Diffraction
Zinc-Lead
spellingShingle Neoproterozoic
Thrust-fold Belt
X-Ray Diffraction
Zinc-Lead
De Oliveira Carvalho, M.
De Morisson Valeriano, C.
González, P.A.A.
Oliveira, G.D.
Impiccini, A.
The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
topic_facet Neoproterozoic
Thrust-fold Belt
X-Ray Diffraction
Zinc-Lead
description Two regional thrust-sheets of Neoproterozoic metasedimentary rocks occur in the Southern Brasilia Belt, northwest Minas Gerais. The lower one comprises the Vazante Group, that is formed in the studied area, from base to top, by the Serra do Garrote (metapelites interlayered with carbonaceous phyllite), Serra do Poco Verde (beige to pink stromatolitic metadolomite with interlayered greenish slates), Morro do Calcario (gray stromatolitic metadolomite interlayered with gray slates) and Serra da Lapa (phyllite with dolarenitic lenses interlayered with slates) formations. The upper thrust sheet consists of the Canastra Group (Paracatu formation): laminated sericite phyllites and carbonaceous phyllites interlayered with quartzite. The Braziliano orogeny resulted in four phases of contractional deformation, associated with low-grade metamorphism. The first two (D1 and D2) are ductile, while the third and fourth ones (D3 and D4) are brittle-ductile. D1 developed a slaty S1 cleavage subparallel to the primary layering, with shallow to steep dips to NW. D2 developed a crenulation cleavage (S2) that dips moderately to NW and is associated with tight to isoclinal folds. D3 and D4 phases developed crenulations and open folds and kink bands. S3 dips steeply to NW, while S4 has moderate to steep dips to NE and SW. White mica crystallinity (Kubler index) measurements in metapelites indicate that both the Canastra and Vazante groups reached anchizone/epizone conditions, and metamorphic discontinuities along thrusts indicate that the peak of metamorphism is pre or syn-thrusting.
format JOUR
author De Oliveira Carvalho, M.
De Morisson Valeriano, C.
González, P.A.A.
Oliveira, G.D.
Impiccini, A.
author_facet De Oliveira Carvalho, M.
De Morisson Valeriano, C.
González, P.A.A.
Oliveira, G.D.
Impiccini, A.
author_sort De Oliveira Carvalho, M.
title The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
title_short The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
title_full The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
title_fullStr The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
title_full_unstemmed The thrust contact between the Canastra and Vazante groups in the Southern Brasília Belt: Structural evolution, white mica crystallinity and implications for the Brasiliano orogeny
title_sort thrust contact between the canastra and vazante groups in the southern brasília belt: structural evolution, white mica crystallinity and implications for the brasiliano orogeny
url http://hdl.handle.net/20.500.12110/paper_23174889_v46_n4_p567_DeOliveiraCarvalho
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