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http://www.repositorio.ufop.br/jspui/handle/123456789/13481
Título : | Strain localization and fluid-assisted deformation in apatite and its influence on trace elements and U–Pb systematics. |
Autor : | Ribeiro, Bruno Vieira Lagoeiro, Leonardo Evangelista Faleiros, Frederico Meira Hunter, Nicholas J. R. Queiroga, Gláucia Nascimento Raveggi, M. Cawood, Peter Anthony Finch, M. Campanha, Ginaldo Ademar da Cruz |
Palabras clave : | Microstructures Apatite recrystallization EBSD - electron backscatter diffraction Dynamic recrystallization Fluid-assisted recrystallization |
Fecha de publicación : | 2020 |
Citación : | RIBEIRO, B. V. et al. Strain localization and fluid-assisted deformation in apatite and its influence on trace elements and U–Pb systematics. Earth and Planetary Science Letters, v. 545, p. 116421, set. 2020. Disponível em: <https://www.sciencedirect.com/science/article/abs/pii/S0012821X20303654>. Acesso em: 19 fev. 2021. |
Resumen : | This paper presents electron backscatter diffraction (EBSD), trace element and U–Pb data of apatite grains from a granitic mylonite from the Taxaquara Shear Zone (SE Brazil). The mylonite recrystallized under upper-greenschist facies and presents two types of apatite with distinct microstructures. Type1 apatite appears in quartz-rich layers and does not exhibit any microstructural, crystallographic, or chemical evidence of deformation/recrystallization, and resembles the original igneous apatite. Type2 apatite appears in mica-rich layers and exhibits core-and-mantle microstructures, and intragranular subgrain development, suggesting that they have undergone dynamic recrystallization. Recrystallized tails of type-2 apatite grains exhibit a strong c-axis crystallographic preferred orientation parallel to the X-direction (stretching lineation), and lack evidence of dislocation density. This evidence from type-2 apatite grains, combined with REE depletion, high La and a negative Ce anomaly compared to type-1 grains, suggests that type-2 apatite tails underwent recrystallization via dissolution-precipitation creep, whereas parental grains underwent crystal-plastic deformation and subgrain formation through dynamic recrystallization. Phase-equilibrium modelling and quartz CPO opening-angle thermometry are consistent with recrystallization at ∼480 – 530◦C and 2.2 – 5.0 kbar. We were not able to determine precise deformation ages from type-2 apatite because fluid-assisted recrystallization appears to have substantially decreased the U/Pb ratio. We find that preferential fluid flow along high-strain, biotite-rich layers in the mylonite caused type-2 apatite to recrystallise, whereas type-1 apatite in low strain layers was unaffected and retained the characteristics of the protolith. |
URI : | http://www.repositorio.ufop.br/jspui/handle/123456789/13481 |
metadata.dc.identifier.uri2: | https://www.sciencedirect.com/science/article/abs/pii/S0012821X20303654 |
metadata.dc.identifier.doi: | https://doi.org/10.1016/j.epsl.2020.116421 |
ISSN : | 0012-821X |
Aparece en las colecciones: | DEGEO - Artigos publicados em periódicos |
Ficheros en este ítem:
Fichero | Descripción | Tamaño | Formato | |
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ARTIGO_StrainLocalizationFluid.pdf Restricted Access | 5,47 MB | Adobe PDF | Visualizar/Abrir |
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