TY - JOUR
T1 - Deformation, thermochronology and tectonic significance of the crustal-scale Cubatão Shear Zone, Ribeira Belt, Brazil
AU - Cabrita, Dina I.G.
AU - Faleiros, Frederico M.
AU - Ribeiro, Bruno V.
AU - Menegon, Luca
AU - Cawood, Peter A.
AU - Campanha, Ginaldo A.C.
N1 - Funding Information:
Dina Cabrita and Frederico Faleiros thank the São Paulo Research Foundation (FAPESP – grants number: 2019/10457-4 , 2018/21824-5 , 2018/10012-0 , 2015/26645-3 and 2015/04487-7 ). Special thanks to Léo Hartmann, Haakon Fossen, and Renata Schmitt for suggestions and manuscript revision. Frederico Faleiros also thanks to the National Council of Technological and Scientific Development (CNPq) for the research productivity grant 307732/2019-3 , and Ginaldo Campanha for grant 305701/2019-3 . Peter Cawood and Bruno Ribeiro acknowledge the Australian Research Council for grant FL160100168 .
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/4/5
Y1 - 2022/4/5
N2 - Crustal-scale shear zones are key structures in orogenic belts linked to the assembly of West Gondwana. The Cubatão Shear Zone (CSZ) represents a significant segment of a crustal-scale transcurrent shear zone system that cuts Paleoproterozoic to Neoproterozoic units in the Ribeira Belt (SE Brazil). Despite its tectonic importance, the relationship between transcurrent deformation and orogenesis is still controversial. This work aims to understand this relationship by integrating the transcurrent deformation history of the CSZ with regional orogenic processes through structural analyses, phase-equilibria modelling, and zircon and apatite U-Pb-REE analyses. The results indicate that the CSZ developed within a transpressional setting with a dominant subhorizontal stretching lineation at medium-temperature conditions of 460–520 °C and 4.5–9.5 kbar, consistent with quartz recrystallisation microstructures indicative of subgrain rotation recrystallisation. Igneous-type apatite from the mylonites of the CSZ record ages of ca. 610–570 Ma, which are interpreted as reset ages due to ductile deformation at medium-temperature conditions. Zircon U-Pb geochronology indicates that mylonites are sourced from the Juquiá Granite and the Atuba Complex. The CSZ activity is coeval with the main period of activity of other ductile shear zones from the Ribeira Belt, as indicated by available geochronological data. This age interval coincides with the main period of other regional shear zones activity, voluminous granitic magmatism, regional metamorphism and convergence of the cratons surrounding the Ribeira Belt, indicating active participation of the transcurrent shear zones in the orogenic processes that built up West Gondwana.
AB - Crustal-scale shear zones are key structures in orogenic belts linked to the assembly of West Gondwana. The Cubatão Shear Zone (CSZ) represents a significant segment of a crustal-scale transcurrent shear zone system that cuts Paleoproterozoic to Neoproterozoic units in the Ribeira Belt (SE Brazil). Despite its tectonic importance, the relationship between transcurrent deformation and orogenesis is still controversial. This work aims to understand this relationship by integrating the transcurrent deformation history of the CSZ with regional orogenic processes through structural analyses, phase-equilibria modelling, and zircon and apatite U-Pb-REE analyses. The results indicate that the CSZ developed within a transpressional setting with a dominant subhorizontal stretching lineation at medium-temperature conditions of 460–520 °C and 4.5–9.5 kbar, consistent with quartz recrystallisation microstructures indicative of subgrain rotation recrystallisation. Igneous-type apatite from the mylonites of the CSZ record ages of ca. 610–570 Ma, which are interpreted as reset ages due to ductile deformation at medium-temperature conditions. Zircon U-Pb geochronology indicates that mylonites are sourced from the Juquiá Granite and the Atuba Complex. The CSZ activity is coeval with the main period of activity of other ductile shear zones from the Ribeira Belt, as indicated by available geochronological data. This age interval coincides with the main period of other regional shear zones activity, voluminous granitic magmatism, regional metamorphism and convergence of the cratons surrounding the Ribeira Belt, indicating active participation of the transcurrent shear zones in the orogenic processes that built up West Gondwana.
KW - Phase equilibria modelling
KW - Quartz EBSD
KW - Transcurrent deformation
KW - West Gondwana
UR - http://www.scopus.com/inward/record.url?scp=85125872402&partnerID=8YFLogxK
U2 - 10.1016/j.tecto.2022.229278
DO - 10.1016/j.tecto.2022.229278
M3 - Article
AN - SCOPUS:85125872402
SN - 0040-1951
VL - 828
JO - Tectonophysics
JF - Tectonophysics
M1 - 229278
ER -