Paleoproterozoic P-T-d-t evolution of a gneiss with quartz-sillimanite nodules from the Azul ranges, Rio de la Plata craton, Argentina

Pressure–temperature–deformation–time path of a deformed garnet-bearing granite from the Paleoproterozoic Tandilia Belt, Río de la Plata Craton of Argentina

“…11). These chemical signatures are similar to monazite of migmatitic gneiss from La Plata hill for which a mean weighted age of 2127 ± 10 (2σ) Ma was determined by Bianchi et al (2020). These authors attributed this monazite to a tectonothermal event prior to the anatexis of the metasedimentary protolith.…”

“…In the area of Cinco Cerros hills, the youngest ages 1913 ± 11 (1σ) Ma and 1805 ± 21 (1σ) Ma were linked to deformation of the continental crust during the final exhumation and slow cooling of the orogen (Massonne et al 2012). A similar interpretation was given for a single monazite age of 1975 ± 18 Ma in the migmatitic gneiss of La Plata hill (Bianchi et al 2020).…”

“…During the last years, several geothermobarometric studies on metamorphic rocks from the TB led to different P-T paths which can be grouped in type I = clockwise paths with cooling during exhumation (Massonne et al 2012;Martínez et al 2017;Bianchi et al 2020), type II = counterclockwise paths with isobaric cooling (Delpino and Dristas 2008) or (2002) showing the position of La Virgen hill and other localities mentioned in the text with increasing pressure during cooling (Martínez et al 2016;Angeletti et al 2017), and type III = clockwise prograde high-P and medium-T paths (Martínez et al 2020). Type I paths were determined for high-grade metasedimentary and metagranitic rocks occurring (1) in the Cinco Cerros area (Fig.…”

“…1b), where quartz-sillimanite nodule-bearing gneiss surpassed the melt-in curve to reach peak metamorphic conditions of ~ 680 °C at 4 kbar. Retrograde back-reactions in the presence of hydrous fluids accompanied by a syntectonic coaxial deformation event (D 1 ) during cooling to ~ 650 °C at 3.8 kbar generated the quartz-sillimanite nodules by K-feldspar dealkalinization (Bianchi et al 2020).…”

“…During the last 20 years, the application of modern dating methodologies, driven by advances in isotope geochemistry, has made it possible to reliably limit the main igneous and metamorphic events of the TB to the Rhyacian until the Statherian of the Paleoproterozoic Era (e.g. Hartmann et al 2002;Cingolani et al 2002;Pankhurst et al 2003;Cingolani et al 2005;Rapela et al 2007;Massonne et al 2012;Angeletti et al 2014;Chernicoff et al 2015;Martínez et al 2017Martínez et al , 2020Bianchi et al 2020). We present a study of small, slightly deformed granite body that contributes to the understanding of the geodynamics of the late collisional evolution forming the Río de la Plata Craton (RPC) in the Rhyacian.…”