Ordovician western Sierras Pampeanas magmatic belt: Record of Precordillera accretion in Argentina

Quenardelle, Sonia; Ramos, Víctor A.

doi:10.1130/0-8137-2336-1.63

Cited by 32 publications

(39 citation statements)

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“…7) (Ramos et al 1986;Ramos 1988;Sims et al 1997Sims et al , 1998Davis et al 1999;Quenardelle and Ramos 1999). This event roughly corresponds to the late to post-Famatinian events of the Famatinian cycle of Dalla Salda et al (1998).…”

Section: Models For the Achalian Orogenymentioning

confidence: 91%

“…Rapela et al (1990) separated granitoids of the Sierras Pampenas into G1, G2 and G3 that roughly correspond in time to the Pampean, Famatinian, and Achalian orogenies. Rapela et al (1998), Quenardelle and Ramos (1999), Pankhurst et al (2000) and Rapela (2000) considered that the Pampean magmatism is arc-related with minor postcollisional peraluminous intrusions. Famatinian magmatism is arc-related and I-type in the west and grades into S-type granitoids toward the continent.…”

Section: Time Constraints For the Famatinian Metamorphismmentioning

confidence: 99%

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The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: an overview

Steenken¹,

Luchi

Dopico

et al. 2010

Int J Earth Sci (Geol Rundsch)

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The Eastern Sierras Pampeanas were structured by three main events: the Ediacaran to early Cambrian (580-510 Ma) Pampean, the late Cambrian-Ordovician (500-440 Ma) Famatinian and the Devonian-Carboniferous (400-350 Ma) Achalian orogenies. Geochronological and Sm-Nd isotopic evidence combined with petrological and structural features allow to speculate for a major rift event (Ediacaran) dividing into two Mesoproterozoic major crustal blocks (source of the Grenvillian age peaks in the metaclastic rocks).This event would be coeval with the development of arc magmatism along the eastern margin of the eastern block. Closure of this eastern margin led to a Cambrian active margin (Sierra Norte arc) along the western margin of the eastern block in which magmatism reworked the same crustal block. Consumption of a ridge segment (input of OIB signature mafic magmas) which controlled granulite-facies metamorphism led to a final collision (Pampean orogeny) with the western Mesoprotrozoic block. Sm-Nd results for the metamorphic basement suggest that the T DM age interval of 1.8-1.7 Ga, which is associated with the less radiogenic values of eNd (540) (-6 to -8), can be considered as the mean average crustal composition for the Eastern Sierras Pampeanas. Increasing metamorphic grade in rocks with similar detrital sources and metamorphic ages like in the Sierras de Córdoba is associated with a younger T DM age and a more positive eNd (540) value. Pampean pre-540 Ma granitoids form two clusters, one with T DM ages between 2.0 and 1.75 Ga and another between 1.6 and 1.5 Ga. Pampean post-540 Ma granitoids exhibit more homogenous T DM ages ranging from 2.0 to 1.75 Ga. Ordovician re-activation of active margin along the western part of the block that collided in the Cambrian led to arc magmatism (Famatinian orogeny) and related ensialic back-arc basin in which high-grade metamorphism is related to mid-crustal felsic plutonism and mafic magmatism with significant contamination of continental crust. T DM values for the Ordovician Famatinian granitoids define a main interval of 1.8-1.6, except for the Ordovician TTG suites of the Sierras de Córdoba, which show younger T DM ages ranging from 1.3 to 1.0 Ga. In Devonian times (Achalian orogeny), a new subduction regime installed west of the Eastern Sierras Pampeanas. Devonian magmatism in the Sierras exhibit process of mixing/assimilation of depleted mantle signature melts and continental crust. Achalian magmatism exhibits more radiogenic eNd (540) values that range between 0.5 and -4 and T DM ages younger than 1.3 Ga. In pre-Devonian times, crustal reworking is dominant, whereas processes during Devonian times involved different geochemical and isotopic signatures that reflect a major input of juvenile magmatism.

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Section: Models For the Achalian Orogenymentioning

confidence: 91%

Section: Time Constraints For the Famatinian Metamorphismmentioning

confidence: 99%

The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: an overview

Steenken¹,

Luchi

Dopico

et al. 2010

Int J Earth Sci (Geol Rundsch)

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“…The Sierras Pampeanas are made from basement cored blocks uplifted during the Andean orogeny (González Bonorino 1950;Allmendinger et al 1983;Jordan et al 1983). Thick-skinned structures were produced by the reactivation of deep crustal discontinuities (Mon & Hongn 1991), basement anisotropies and faults formed during Precambrian to Palaeozoic orogenies (Mon & Hongn 1991;Cristallini et al 2004;Quenardelle & Ramos 1999). The tectonic inversion of former extensional faults played a key role in the configuration of the Santa Bárbara System, at the NE of the study area (Grier et al 1991;Coutand et al 2001;Kley et al 2005;Carrera et al 2006;Hongn et al 2007).…”

Section: Geological Settingmentioning

confidence: 99%

Basin fragmentation controlled by tectonic inversion and basement uplift in Sierras Pampeanas and Santa Bárbara System, northwest Argentina

Iaffa

Sàbat

Muñoz

et al. 2013

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The study area is located within the Central Andes, a complex region composed of different structural styles. The region is characterized by highly elevated basement cored ranges, which abruptly break the foreland plain. These ranges were uplifted mainly by deep detached high-angle faults or by the inversion of former extensional faults of the Cretaceous rift. Palaeozoic orogenies generated crustal scale discontinuities in the basement, some of them reactivated during the Andean orogeny. Sedimentary sequences and layers architecture in the basins bordering ranges recorded the tectonic evolution of the region. Basement, syn–rift, post-rift and three foreland stages were interpreted in the seismic sections according to the arrangement of the horizons and the main outcropping geological units in bordering ranges. Based on seismic data sets and field data, here we document a particular style of activation of basement faults. Thick-skinned structures that are not always related to the tectonic inversion but to the reactivation of older basement anisotropies represent a paradox since they were not active during the rifting stage. A flat slab subduction and a subsequent angle recovery conditioned the structural evolution of the area.

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“…Subduction related granites regarded as Cordilleran-type plutonism [Rapela et al, 1992] go back to, at least, $490 Ma and have been linked to an initial, precollisional Andean-type margin. Coeval plutonism at the Sierra de Ancasti and Sierra de Quilmes (northern Sierras Pampeanas, east of Famatina) point to a back arc setting [Rapela et al, 1990;Quenardelle and Ramos, 1999;Rapela, 2000b], whereas the Famatina ranges would represent the main arc.…”

Section: Ordovician Magmatismmentioning

confidence: 99%

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

2004

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The Famatina belt, southern central Andes, records a circa 470 m.y. shortening episode (Ocloyic orogeny) affecting the peri‐Gondwanan back arc basin in response to the accretion of the Precordillera terrane. Collision created distinct features across and along the margin, some of which persisted into the present Andean structure. From east to west, the Ocloyic deformation is recorded across the telescoped region of Famatina, represented by (1) an east vergent fold‐thrust belt (EVFTB) involving a major angular unconformity between Early and Middle Ordovician rocks, (2) a highly deformed volcano‐sedimentary belt, and (3) an east vergent ductile shear zone affecting Famatinian granites. Axis attitudes of Ordovician refolded anticlines in the EVFTB show west‐east tectonic transport, in agreement with kinematics of Ocloyic high‐strain belts, indicating shortening orthogonal to the present Pacific margin. Eastward displacement of the Ordovician volcanic arc at ∼27°S latitude together with a documented sinistral slip zone across the proto‐Andean margin suggests tectonic indentation.

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Ordovician western Sierras Pampeanas magmatic belt: Record of Precordillera accretion in Argentina

Cited by 32 publications

References 0 publications

The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: an overview

The Neoproterozoic-early Paleozoic metamorphic and magmatic evolution of the Eastern Sierras Pampeanas: an overview

Basin fragmentation controlled by tectonic inversion and basement uplift in Sierras Pampeanas and Santa Bárbara System, northwest Argentina

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

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