The Río de la Plata Craton of Argentina and Uruguay

Oyhantçabal, Pedro; Cingolani, Carlos Alberto; Wemmer, Klaus; Siegesmund, Siegfried

doi:10.1007/978-3-319-68920-3_4

Cited by 31 publications

(41 citation statements)

References 53 publications

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“…The granitic–gneissic Tacuarembó, Piedra Alta and Nico Perez Terranes are located on the Western Sul‐Rio‐Grandense and Uruguayan Shields. These terranes yield Orosirian to Archean ages, with peaks from 1.8 to 2.2 Ga (Oyhantçabal et al ., ,b). In general, there is a westward increase in the age of terranes; however, exceptions occur like the Neoproterozoic magmatism in both the Tacuarembó and Nico Pérez blocks (Oyhantçabal et al ., ,b), and Palaeoproterozoic successions are present as the Rhyacian Rio dos Ratos Complex and Encantadas Block in the east (Gregory et al ., ).…”

Section: Geological Contextmentioning

confidence: 99%

Controls on Early Cretaceous desert sediment provenance in south‐west Gondwana, Botucatu Formation (Brazil and Uruguay)

et al. 2020

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The Lower Cretaceous Botucatu Formation records the development of widespread dry–aeolian desert sedimentation throughout the Paraná Basin in south‐west Gondwana. To reconstruct the provenance of the aeolian sediment, petrography, granulometric analysis, U‐Pb detrital zircon ages have been determined from along the southern basin margin in Rio Grande do Sul state (southern Brazil) and Uruguay (Tacuarembó region). The dataset reveals a mean composition Qt89F8L3, comprising very fine to medium‐grained quartozose and feldspatho‐quartzose framework. Heavy mineral analysis reveals an overall dominance of zircon, tourmaline and rutile grains (mean ZTR0.84) with sporadic garnet, epidote and pyrolusite occurrences. The detrital zircon U‐Pb ages are dominated by Cambrian to Neoproterozoic (515 to 650 Ma), Tonian to Stenian (900 to 1250 Ma) and Orosirian to Rhyacian (1.8 to 2.2 Ga) material. The detrital zircon dataset demonstrates a significant lateral variation in sediment provenance: Cambrian to Neoproterozoic detrital zircons dominate in the east, while Tonian to Stenian and Orosirian to Rhyacian ages predominate in the west of the study area. Sandstones are quartz‐rich with dominantly durable zircon, tourmaline and rutile heavy mineral suite, with subtle but statistically significant along‐strike differences in heavy mineral populations and detrital mineralogy which are thought to record local sediment input points into the aeolian system. The similar age spectra of Botucatu desert with proximal Paraná Basin units, the predominance of quartzose, and zircon, tourmaline and rutile components, suggests that recycling is the mechanism responsible for the erg feeding.

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Section: Geological Contextmentioning

confidence: 99%

Controls on Early Cretaceous desert sediment provenance in south‐west Gondwana, Botucatu Formation (Brazil and Uruguay)

et al. 2020

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“…The most convincing arguments in favor of this configuration are that no Archean model ages have yet been determined for Piedra Alta Terrane samples, suggesting that the terrane was formed rapidly from a juvenile source, in contrast with the protracted history suggested for the Tandilia Terrane. Whatever the case, and emphasizing similarities instead of differences, Oyhantçabal et al (2018) put forward the reinterpretation that similar isotope data from samples taken in all areas of the RPC could indicate that the Based on the analogous isotopic signature of SA granodiorite and gneiss it is assumed that a single magmatic event gave rise to these rocks, whose ages of crystallization range between 2.1 and 2 Ga, and have an average of 2.5 Ga T DM age for new crust extraction from the mantle. This Trans-Amazonian magmatic event is predominantly juvenile, followed by crustal recycling.…”

Section: Regional Correlation Of Magmatic Eventsmentioning

confidence: 99%

“…1). It has been studied in recent decades using geochronology, mapping and geochemistry (Almeida et al, 1973;Pankhurst et al, 2003;Rapela et al, 2011;Oyhantçabal et al, 2011Oyhantçabal et al, , 2018Cingolani, 2011). The largest outcrop of the RPC in Argentina is found in the Tandilia belt.…”

Section: Introductionmentioning

confidence: 99%

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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“…Gravimetric interpretation from sections modeled with the GMSYS ® program in the Quilmes Trough suggests the presence of an extensional depocenter limited by high angle faults similar to the morphology of the Santa Lucia Basin (Figure 8). A map of Bouguer anomalies of the study area shows the relationship between the main gravimetric highs of the NEE and the San José and Montevideo mobile belts (Rapela et al, 2007;Oyhantçabal et al, 2018) and the continuity of these gravimetric features below the Rio de la Plata estuary and the margin of the Buenos Aires province (Figure 8). This map was created from Uruguay's terrestrial gravimetric stations (approximately 30,000), while for the rest of the study area the data was obtained from a Bouguer anomaly grid provided by the World Gravity Map 2012 (available on the website of Bureau Gravimétrique International).…”

Section: The Rio De La Plata Geological Settingmentioning

confidence: 99%

Shallow intraplate seismicity in the Buenos Aires province (Argentina) and surrounding areas: is it related to the Quilmes Trough?

2020

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In the light of the November 30th, 2018 (N30) earthquake activity, some neighborhoods of the city of Buenos Aires were shaken by a 3.8 mb earthquake (4.53 km estimated depth). We examined the historical and recent seismic records in order to analyze possible mechanisms related to the distribution of tectonic stresses as responsible for such unusual earthquakes in a region where only very little seismic activity is reported. According to this, at list one historical event occurred on June 5th, 1888 and other small magnitude earthquakes are mentioned since 1848 interpreted as being associated with the Rio de la Plata faulting. But there is, still no consensus about the role of this structure compared to other structures with orientation SW-NE. The lack of evidence to support one over the other structures makes it difficult to analyze these earthquakes. The presence of the Quilmes Trough connecting the Santa Lucía Basin in Uruguay and the Salado Basin in Argentina was recently proposed to play a tectonic role by a system of ENE-WSW trending controlled by extensional faulting related to the beginning of the Gondwana breakup. This depocenter with a thickness of almost 2,000 m of Mesozoic and Tertiary sequences could be acting as a zone of weakness in the crust and therefore responsible for the mentioned earthquake activity. The orientation of this structure correlates well with the present convergence vector between the Nazca and the South American plates and could therefore be propitious for strain release triggering shallow intraplate seismicity. We propose that most of the epicenters from historical and recent earthquakes might be aligned sub-parallel to the principal axis of the Quilmes Trough. Nevertheless, more data is needed to produce a reliable earthquake monitoring system in order to elucidate the tectonic stress regime and the existence of such structures at depth

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The Río de la Plata Craton of Argentina and Uruguay

Cited by 31 publications

References 53 publications

Controls on Early Cretaceous desert sediment provenance in south‐west Gondwana, Botucatu Formation (Brazil and Uruguay)

Controls on Early Cretaceous desert sediment provenance in south‐west Gondwana, Botucatu Formation (Brazil and Uruguay)

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

Shallow intraplate seismicity in the Buenos Aires province (Argentina) and surrounding areas: is it related to the Quilmes Trough?

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