The Pacific Gondwana margin in the late Neoproterozoic–early Paleozoic: Detrital zircon U–Pb ages from metasediments in northwest Argentina reveal their maximum age, provenance and tectonic setting

Adams, Christopher; Miller, Hubert; Aceñolaza, Florencio Gilberto; Toselli, Alejandro J.; Griffin, William L.

doi:10.1016/j.gr.2010.05.002

Cited by 118 publications

(107 citation statements)

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“…9) show two main age clusters, the older one between 509 and 536 Ma and the younger between 452 and 485 Ma. The older values reflect inherited ages of the detrital sources of the Puncoviscana and La Paya (or equivalent) formations, while the younger cluster should be linked to the Ordovician metamorphism and magmatism (Lork et al, 1989;Lork and Bahlburg, 1993;Haschke et al, 2005;Viramonte et al, 2007;Sola et al, 2010;Einhorn, 2010;Adams et al, 2011;Hauser et al, 2011). These valisotope compositions, according to the model of Stacey and Kramers (1975).…”

Section: Discussionmentioning

confidence: 94%

“…The Puncoviscana Formation encompasses a thick and complex metaturbiditic sequence whose Neoproterozoic to Early Cambrian age is constrained by trace fossils, ages from detrital zircons and volcanic intercalations, and by the Early Cambrian intrusion of the Cañaní and Santa Rosa de Tastil granite batholiths (Bachman et al, 1987;Aceñolaza and Toselli, 2009;Hongn et al, 2010;Adams et al, 2011;Augustsson et al, 2011;Escayola et al, 2011). The study of the Puncoviscana Formation has fostered conflicting interpretations concerning the tectonic setting prevailing during its formation (Keppie and Bahlburg, 1999).…”

Section: Regional Settingmentioning

confidence: 99%

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The Sierra de Cachi (Salta, NW Argentina): geological evidence about a Famatinian retro-arc at mid crustal levels

Hongn¹,

Tubía²,

Esteban³

et al. 2014

Journal of Iberian Geology

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The Cachi mountain ranges, located in Salta (NW Argentina), form an inlier where Neoproterozoic and Paleozoic materials of the Andes crop out in a plutono-metamorphic dome surrounded by Mesozoic and Cenozoic sedimentary rocks. The pre-Mesozoic rocks record a regional metamorphism of low pressure and high temperature conditions, which reached partial melting conditions and was coeval with the intrusion of sheeted granite and trondhjemite plutons. The metamorphic evolution and the emplacement of the plutons took place in an extensional tectonic setting. New U-Pb zircon dating by TIMS and SHRIMP methods yields similar ages for the migmatization (479.7 ± 3.5 Ma) and the emplacement of granites (472.1 ± 11 Ma), constraining the extensional event to Early Ordovician times. We also report the finding of gabbro boulders, which also yield a similar U-Pb SHRIMP zircon age of 477.5 ± 3.9 Ma. So, we propose that the extensional event recognized in Sierra de Cachi took place in a retro-arc setting linked to the Famatinian subduction along the western border of Gondwana. The shortening produced by younger east-verging folds evidences the superposition of a compressional stress field, probably related with the Ocloyic orogeny (Middle/Late Ordovician-Devonian).Keywords: U-Pb geochronology, Famatinian retro-arc, Cachi ranges, Argentina Resumen En la Sierra de Cachi, situada en Salta (NO de Argentina), afloran rocas neoproterozoicas y paleozoicas de los Andes en un domo plutono-metamórfico flanqueado por rocas sedimentarias mesozoicas y cenozoicas. Estas rocas registran un metamorfismo de alta temperatura y baja presión, que alcanzó condiciones de fusión parcial y fue coetáneo del emplazamiento de plutones de granitos y trondhjemitas. El metamorfismo y el emplazamiento de los plutones se produjo en condiciones extensionales. Nuevos análisis de U-Pb en zircones, por los métodos TIMS y SHRIMP, proporcionan edades similares para la migmatización (479,7 ± 3,5 Ma) y el emplazamiento de los granitos (472,1 ± 11 Ma), acotando el evento extensional al Ordovícico Inferior. También describimos el hallazgo de bloques de gabros que dan una edad U-Pb SHRIMP en circones semejante, de 477,5 ± 3,9 Ma. Por lo tanto, se propone que el evento extensional descrito en la Sierra de Cachi tuvo lugar en una zona de retro-arco asociada a la subducción famatiniana del borde occidental de Gondwana. El acortamiento producido por los pliegues más jóvenes vergentes al E refleja la superposición de un campo de esfuerzos compresivos, probablemente relacionados con la orogenia Oclóyica (Ordovícico Medio/Superior-Devónico).Palabras clave: geocronología U-Pb, retro-arco famatiniano, Sierra de Cachi, Argentina

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Section: Discussionmentioning

confidence: 94%

Section: Regional Settingmentioning

confidence: 99%

The Sierra de Cachi (Salta, NW Argentina): geological evidence about a Famatinian retro-arc at mid crustal levels

Hongn¹,

Tubía²,

Esteban³

et al. 2014

Journal of Iberian Geology

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“…Based on U-Pb geochronology of detrital zircons, and the pre-depositional Santa Rosa de Tastil batholith, Augustsson et al (2011) suggest a mainly middle Cambrian depositional age for the Meson Group. Adams et al (2011) report a youngest zircon component at 500 Ma, suggesting an upper age limit of Late Cambrian for the Meson Group.…”

Section: Introductionmentioning

confidence: 85%

Provenance and tectonic setting of Neoproterozoic to Early Cambrian metasedimentary rocks from the Cordillera Oriental and Eastern Sierras Pampeanas, NW Argentina

Piñán-Llamas

Escamilla-Casas

2013

BSGM

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Major, trace, and rare-earth element data for the Neoproterozoic to early Cambrian Puncoviscana Formation and related highergrade metasedimentary rocks in Eastern Sierras Pampeanas, NW Argentina, were analyzed to evaluate their provenance, weathering, and tectonic setting during the upper Neoproterozoic-lower Paleozoic. The studied rocks are metapelites and metapsammites that were mainly affected by the lower Cambrian Pampean orogeny. Geochemical analyses indicate that the Puncoviscana Fm. and related rocks are characterized by moderate Chemical Index of Alteration (CIA) values. REE element distributions, Eu/Eu* values, and high Zr/Sc and Th/Sc ratios indicate that the samples were likely derived from predominantly upper-crust felsic sources. Tectonic discrimination diagrams based on immobile trace elements (e.g. Th-La-Sc, Sc-Th-Zr/10), multi-element patterns, REE characteristics, and diagnostic trace element ratios (i.e. Th/Sc, Zr/Hf, La/Th, La/Sc) imply that the tectonic setting of the source area was a continental island arc and/ or an active continental margin. Geochemical signatures of low-grade metapsammitic samples (high Hf and Zr content, and high Zr/ Sc ratios) indicate crustal recycling.The geometry and sequence of structures and microstructures preserved in all samples are pervasive and suggest a common and uniform deformational history during the Pampean orogeny. Geochemical signatures and structures of the studied samples are consistent with protolithic sediments of the Puncoviscana Fm. and related rocks initially deposited in an arc-related basin that was subsequently deformed during the Pampean orogeny.Keywords: Geochemistry, metasedimentary rocks, provenance, Pampean orogeny, Puncoviscana Formation. petrographic studies. Major and trace elements can constraint the effects of weathering and sedimentary sorting, while rare earth and certain trace elements (e.g. Th, Zr, Hf, Nb, and Sc) are considered particularly reliable in the discrimination of provenance and tectonic setting. This reliability is based on their low mobility during sedimentary processes, diagenesis, and metamorphism, thus reflecting the signature of the parent materials, and the composition and tectonic environment of the source (Taylor and McLennan, 1985;McLennan, 1989;McLennan et al., 1993;Roser et al., 1996;Condie, 1991Condie, , 1993. Provenance studies of medium and high metamorphic grade metasediments are relatively common in the literature (i.e. Li et al., 2005;Meinhold et al., 2007;Drobe et al., 2011; Verdecchia and Baldo, 2010). ResumenIn this paper, we present new major and trace element whole-rock geochemical analyses from the Puncoviscana Fm. and related metasedimentary rocks from Cumbres Calchaquies, Sierras de Quilmes, Ancasti, and Córdoba (Figure 1). We combine our results with previously published data Do Campo and RibeiroGuevara, 2005;Zimmermann, 2005) to evaluate their source and tectonic depositional setting. The characterization of the provenance and tectonic setting of these units is important for unde...

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“…Las rocas de este complejo muestran patrones de edades de circones detríticos similares a los de los CMLL y CMC, registrando el pico de edades más jóvenes en 520-530 Ma, correspondiente a la orogénesis Pampeana, y edades típicas del Cratón del Río de La Plata (ca. 2,1 Ga; Finney et al, 2003Finney et al, , 2004Rapela et al, 2007;Adams et al, 2011;Verdecchia et al, 2011). Por otra parte, las edades de sedimentación máxima y mínima de los protolitos del Complejo Metamórfico Pringles (CMP) están acotadas por la edad de herencia en circones detríticos ca.…”

Section: Correlación Con Otros Complejos Metamór-ficos De Las Sierrasunclassified

“…500-440 Ma), a las que siguen eventos más discretos de magmatismo y deformación devónico-carboníferos asociados a la orogenia Achaliana (e.g., Rapela et al, 1998;Sims et al, 1998;Pankhurst et al, , 2000Dahlquist et al, 2010;Otamendi et al, 2008Otamendi et al, , 2012Rapela et al, 2007;Siegesmund et al, 2010;Steenken, et al, 2011;Casquet et al, 2012). En la última década se ha incrementado significativamente la información geoquímica, isotópica y geocronológica (especialmente U-Pb en circones detríticos) de las rocas metasedimentarias de la región de las Sierras Pampeanas Orientales (e.g., Sims et al, 1998;López de Luchi et al, 2003;Escayola et al, 2007;Rapela et al, 2007;Collo et al, 2009;Drobe et al, 2009Drobe et al, , 2011Verdecchia y Baldo, 2010;Adams et al, 2011;Verdecchia et al, 2011;Murra et al, 2011;Larrovere et al, 2012;Iannizzotto et al, 2013), permitiendo discriminar las diferentes paleocuencas, principalmente aquellas que funcionaron durante el Neoproterozoico tardío al Ordovícico temprano.…”

Section: Introductionunclassified

Geoquímica de las rocas metasedimentarias del Cámbrico medio al Ordovícico temprano de la Sierra de Los Llanos (Sierras Pampeanas, Argentina): Fuente de sedimentos, correlación y ambiente geotectónico

Verdecchia

Murra

Baldo

et al. 2014

Andgeo

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RESUMEN.El complejo metamórfico de la Sierra de Los Llanos está constituido por rocas paraderivadas metamorfizadas en condiciones de bajo a alto grado y representadas por filitas, esquistos, gneises y migmatitas que afloran como grandes septos dentro de las unidades magmáticas del Ordovícico inferior. Localmente se reconocen rocas corneanas asociadas a la intrusión de cuerpos de composición básica. Las rocas metasedimentarias de este complejo muestran composiciones químicas equivalentes a pelitas y areniscas del tipo sublitoarenita y subarcosa. Las relaciones de Ti/Zr (5,(4)(5)(6)(7)(8)4), La/Sc (5,2-8,5), Th/Sc >1 (2,2-3,4), La/Th (2,0-2,5) y Zr/Sc (60-103), junto a las concentraciones de Hf (7,9 a 12,4 ppm) y Sc (4,4-5,2 ppm) en las metapsamitas son indicativas de una fuente enriquecida en componentes félsicos o de materiales reciclados y con reducida participación de componentes máficos. La correlación geoquímica de estas unidades con las metapsamitas de los complejos metamórficos Chepes, La Cébila y Pringles sugiere una misma composición del área fuente para todos ellos. Las concentraciones de Ti, Zr, Hf, La, Th y Sc son variables y no permiten definir claramente un determinado contexto geotectónico, sugiriendo además que la composición de los protolitos fue mayormente controlada por procesos sedimentarios y no por la heterogeneidad composicional de las fuentes. La integración de la información geoquímica con los datos geocronológicos conocidos y la correlación regional de los complejos metamórficos ordovícicos permite reforzar la propuesta de definir como principales áreas fuente de estos complejos las rocas ígneas y metamórficas de la faja orogénica Pampeana y del Cratón del Río de La Plata. La información aportada es consistente, además, con la existencia de una extensa plataforma continental en el margen suroccidental de Gondwana durante el Cámbrico medio al Ordovícico temprano. Palabras clave: Complejo Metamórfico Los Llanos, Geoquímica de rocas metasedimentarias, Cámbrico tardío, Orogénesis Pampeana, Orogénesis Famatiniana, Sierras Pampeanas Orientales.381 Verdecchia et al. / Andean Geology 41 (2): 380-400, 2014 ABSTRACT. Geochemistry of middle Cambrian to early Ordovician metasedimentary rocks of the Sierra de Los Llanos (Sierras Pampeanas, Argentina): Source of sediments, correlations and geotectonic setting. The metamorphic complex of Sierra de Los Llanos is composed of low-to high-grade metasedimentary rocks, namely phyllites, schists, gneisses and migmatites that out crop like large septa within lower Ordovician magmatic units. Cornubianite associated with the intrusion of basic composition bodies are locally recognized. Chemical compositions of these metasedimentary rocks are equivalent to pelite and arenite (sublitharenite-subarkose). Chemical ratios of Ti/Zr (5.4-8.4), La/Sc (5.2-8.5), Th/Sc >1 (2.2-3.4), La/Th (2.0-2.5) and Zr/Sc (60-103), along with contents of Hf (7.9 a 12.4 ppm) and Sc (4.4-5.2 ppm) in meta-psammites, suggest that the source of the sediments was enriched in felsic compon...

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The Pacific Gondwana margin in the late Neoproterozoic–early Paleozoic: Detrital zircon U–Pb ages from metasediments in northwest Argentina reveal their maximum age, provenance and tectonic setting

Cited by 118 publications

References 45 publications

The Sierra de Cachi (Salta, NW Argentina): geological evidence about a Famatinian retro-arc at mid crustal levels

The Sierra de Cachi (Salta, NW Argentina): geological evidence about a Famatinian retro-arc at mid crustal levels

Provenance and tectonic setting of Neoproterozoic to Early Cambrian metasedimentary rocks from the Cordillera Oriental and Eastern Sierras Pampeanas, NW Argentina

Geoquímica de las rocas metasedimentarias del Cámbrico medio al Ordovícico temprano de la Sierra de Los Llanos (Sierras Pampeanas, Argentina): Fuente de sedimentos, correlación y ambiente geotectónico

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