Timing of deformation in the Sarandí del Yí Shear Zone, Uruguay: implications for the amalgamation of western Gondwana during the Neoproterozoic Brasiliano-Pan-African Orogeny

 

Autor(es):

Oriolo, S. ; Oyhantçabal Cironi, Pedro Bernarndo ; Wemmer, K. ; Basei, M. A. S. ; Benowitz, J. ; Pfänder, J. ; Hannich, F. ; Siegesmund, S.

Tipo:

Artículo

Versión:

Publicado

Resumen:

U-Pb and Hf zircon (sensitive high-resolution ion microprobe -SHRIMP- and laser ablation-inductively coupled plasma-mass spectrometry -LA-ICP-MS-), Ar/Ar hornblende and muscovite, and Rb-Sr whole rock-muscovite isochron data from the mylonites of the Sarandí del Yí Shear Zone, Uruguay, were obtained in order to assess the tectonothermal evolution of this crustal-scale structure. Integration of these results with available kinematic, structural, and microstructural data of the shear zone as well as with geochronological data from the adjacent blocks allowed to constrain the onset of deformation along the shear zone at 630-625 Ma during the collision of the Nico Pérez Terrane and the Río de la Plata Craton. The shear zone underwent dextral shearing up to 596 Ma under upper to middle amphibolite facies conditions, which was succeeded by sinistral shearing under lower amphibolite to upper greenschist facies conditions until at least 584 Ma. After emplacement of the Cerro Caperuza granite at 570 Ma, the shear zone underwent only cataclastic deformation between the late Ediacaran and the Cambrian. The Sarandí del Yí Shear Zone is thus related to the syncollisional to postcollisional evolution of the amalgamation of the Río de la Plata Craton and the Nico Pérez Terrane. Furthermore, the obtained data reveal that strain partitioning and localization with time, magmatism emplacement, and fluid circulation are key processes affecting the isotopic systems in mylonitic belts, revealing the complexity in assessing the age of deformation of long-lived shear zones

Año:

2016

Idioma:

Inglés

Temas:

Argon lasers
Binary alloys
Deformation
Geochronology
Inductively coupled plasma mass spectrometry
Laser ablation
Lead alloys
Metals
Mica
Rubidium alloys
Shearing
Silicate minerals
Strontium alloys
Tectonics
Timing circuits
Uranium alloys
Zircon
Amphibolite facies
Cataclastic deformation
Crustal-scale structure
Fluid circulation
Isotopic systems
Sensitive high-resolution ion microprobe
Strain partitioning
Shearing machines
age determination
deformation
emplacement
geochronology
Gondwana
Pan African orogeny
Proterozoic
Shear zone
Strain partitioning
Tectonic evolution
Thermal evolution
Uruguay

Institución:

Universidad de la República

Repositorio:

COLIBRI

Enlace(s):

https://hdl.handle.net/20.500.12008/22041

Nivel de acceso:

Acceso abierto