Microstructural analysis and P–T conditions of the Azul megashear zone, Tandilia, Buenos Aires province, Argentina

Frisicale, María Cristina; Martínez, Francisco J.; Dimieri, Luis Vicente; Dristas, Jorge A.

doi:10.1016/j.jsames.2005.06.006

Cited by 17 publications

(15 citation statements)

References 16 publications

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“…The similarity between amphibolite and sanukitoid patterns is remarkable, especially as regards negative anomalies of Nb and Ti. Nb, Y, Ta and Yb trace-element values for all SA samples, as well as previously-published basement analyses from Tandilia (Di Paola and Espiasse, 1986;Dalla Salda et al, 1992;Di Paola, 1995;Iacumin et al, 2001;Frisicale et al, 2005;Martínez and Dristas, 2007;Jorgensen et al, 2008;Frisicale et al, 2012;Massonne et al, 2012), were plotted on the tectonic discrimination diagrams devised by Pearce et al (1984), showing similar values for volcanic arc and syn-collisional granitoids (Fig. 12).…”

Section: Whole Rock Geochemistrysupporting

confidence: 76%

“…Fig.6. Geochemistry diagrams from Siempre Amigos Hills rocks and comparison with previous chemical data for Paleoproterozoic basement of Tandilia(Martínez and Dristas, 2007;Dalla Salda et al, 1992;Jorgensen et al, 2008;Frisicale et al, 2005;Di Paola and Espiasse, 1986;Di Paola, 1995;Iacumin et al, 2001;Frisicale et al, 2012;Massonne et al, 2012). (a) TAS (LeBas et al, 1986).…”

mentioning

confidence: 78%

“…Representative whole rock analyses are listed in Table 1. The main geochemical features are compared with a compilation of similar chemical data published to date for the Paleoproterozoic basement of Tandilia (Di Paola and Espiasse, 1986;Dalla Salda et al, 1992;Di Paola, 1995;Iacumin et al, 2001;Frisicale et al, 2005;Martínez and Dristas, 2007;Jorgensen et al, 2008;Frisicale et al, 2012;Massonne et al, 2012).…”

Section: Whole Rock Geochemistrymentioning

confidence: 99%

“…U-Th-Pb isotopic analyses of 31 representative zircon grains from (Martínez and Dristas, 2007;Dalla Salda et al, 1992;Jorgensen et al, 2008;Frisicale et al, 2005;Di Paola and Espiasse, 1986;Di Paola, 1995;Iacumin et al, 2001;Frisicale et al, 2012;Massonne et al, 2012).…”

Section: Gneiss Of Intermediate Composition (Sample 1008)mentioning

confidence: 99%

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New geochemical, U–Pb SIMS geochronology and Lu–Hf isotopic data in zircon from Tandilia basement rocks, Río de la Plata craton, Argentina: Evidence of a sanukitoid precursor for some Paleoproterozoic granitoids

Angeletti

Chichorro

Castro

et al. 2021

Journal of South American Earth Sciences

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In this paper new geochemical, geochronological and isotopic Lu-Hf data from the Siempre Amigos Hills (SA), western Tandilia, Argentina, is presented. Outcrops in this small area include representative lithologies of the basement Río de la Plata craton (RPC) known as Tandilia Terrane. The new geochemical data characterize a heterogeneous Paleoproterozoic crust with a similar U-Pb SIMS magmatic age (~2.1 Ga) represented by a suite of mafic (amphibolites, charnockitic granulites), intermediate and felsic compositions (diorites, granodiorites and granitic gneisses), as well as intrusive granitic rocks (with Neoproterozoic age of ~652 Ma in zircon). Geochemical features suggest processes of magmatic differentiation from a mafic igneous protolith associated with the 'Camboriu orogeny' of the Trans-Amazonian-Eburnean cycle. Some amphibolites may represent sanukitoid magmas similar to those formed at the Archean-Proterozoic transition. This paper examines the hypothesis of a sanukitoid precursor for RPC Rhyacian magmatism. The potassic and calc-alkaline character of magmatic series, together with negative Nb-Ta-Ti anomalies and REE patterns, are compatible with classical modern subduction-related magmas. Precise Lu-Hf analyses of zircons collected from a granodiorite and a gneiss indicate a predominantly juvenile source (+εHf), with minor crustal recycling (-εHf). An inheritance age is recorded in a single Neoarchaean zircon core from a granodiorite (2771 ± 15 Ma), similar to calculated maximum Hf T DM (2.8 Ga). Considering the new available data from this region of the RPC, a sustainable petrogenetic model is proposed to explain the presence of geochemical and isotopic evidence of sanukitoid magmatism which may have occurred after 2.7 Ga, which seems to constitute a magmatic series which is a precursor to the development of the Rhyacian magmatic arc in the Tandilia Terrane. Medium-to high-grade metamorphic conditions probably resulted from Paleoproterozoic subduction followed by the intrusion of huge volumes of Rhyacian calc-alkaline magmatism. This model is compatible with RPC configuration as a collage of terranes, and also consistent with Trans-Amazonian-Eburnean amalgamation of various microcontinents in the formation of Atlantica.

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Section: Whole Rock Geochemistrysupporting

confidence: 76%

mentioning

confidence: 78%

Section: Whole Rock Geochemistrymentioning

confidence: 99%

Section: Gneiss Of Intermediate Composition (Sample 1008)mentioning

confidence: 99%

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New geochemical, U–Pb SIMS geochronology and Lu–Hf isotopic data in zircon from Tandilia basement rocks, Río de la Plata craton, Argentina: Evidence of a sanukitoid precursor for some Paleoproterozoic granitoids

Angeletti

Chichorro

Castro

et al. 2021

Journal of South American Earth Sciences

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show abstract

“…The shear-sense indicators point to dextral shearing, where a pure shear component is active during transpressive deformation (Cingolani et al 2002 and references therein). Frisicale et al (2007) estimated the P-T conditions at 400-450°C and 6 kbar during the deformation in the Azul megashear zone of Tandilia. Pankhurst et al (2003) reported Sm-Nd T DM on granitoids from the Tandilia Belt ranging between 2.53 and 2.68 Ga, indicating the main period of crust formation was late Archean to Paleoproterozoic.…”

Section: Geological Overview Of the Río De La Plata Cratonmentioning

confidence: 99%