History of crustal growth and recycling at the Pacific convergent margin of South America at latitudes 29°–36° S revealed by a U–Pb and Lu–Hf isotope study of detrital zircon from late Paleozoic accretionary systems

Willner, Arne P.; Gerdes, Axel; Massonne, Hans‐Joachim

doi:10.1016/j.chemgeo.2008.04.016

Cited by 127 publications

(164 citation statements)

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“…1a), north of Los Vilos (30º -31º latitude S), Palaeozoic basement rocks were studied by Rebolledo (1987), Godoy and Charrier (1991) and Rebolledo and Charrier (1994), who proposed a late Carbon-, who proposed a late Carboniferous -Permian age for the accretionary process. New data have been recently reported on the metamorphic processes that affected these rocks and the chronology of their evolution (Willner, 2005;Willner et al, 2008Willner et al, , 2012. The detailed study of the structure, microstructure and metamorphism of these rocks has permitted us to construct a geological crosssection and to establish their tectono-metamorphic evolution.…”

Section: Introductionmentioning

confidence: 99%

Structure of the Andean Palaeozoic basement in the Chilean coast at 31º 30’ S: Geodynamic evolution of a subduction margin

Garcı́a-Sansegundo

Farias

Heredia

et al. 2014

Journal of Iberian Geology

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The Palaeozoic basement outcropping to the north of Los Vilos is formed by (i) the Choapa Metamorphic Complex (ChMC) made of metabasites (amphibolites and retrogressed eclogites), fine-grained gneisses, schists and quartz-schists, and (ii) the meta-sedimentary and sedimentary rocks of the Arrayán and Huentelauquén formations respectively. Near Huentelauquén (31º 30' S), the ChMC has been affected by three deformation episodes related with the Gondwanan orogenic episode. The first episode (D1) is represented by a foliation (S1) formed under HP-LT metamorphic conditions and preserved in syn-D2 garnet and albite porphyroblasts. A generalised crenulation cleavage (S2) was developed under pressure decreasing conditions during the second deformation episode (D2). This episode is responsible for the exhumation of the ChMC, which took place through an east-directed reverse fault system that thrusts the ChMC over the Arrayán Formation, producing more than 20 km shortening. The third deformation episode (D3) is represented by a west-verging kilometre-scale anticline, with a thrust in its reverse limb (Las Caldas thrust). Minor folds and crenulations are also associated with D3. D3 structures affect the ChMC and the Arrayán Formation and are responsible for the overturning of the D2 thrusts. The Huentelauquén Formation, late Carboniferous -Permian in age, is the latest unit deformed by Gondwanan structures. The characterisation of the structure and its relation to metamorphism in the study area, lead to propose a geodynamic model related with an Andean type non-collisional orogenic process, for the Gondwanan orogenic episode of the Andes at this latitude.Keywords: Gondwanan structure, tectono-metamorphic evolution, Choapa Metamorphic Complex, Chile, system thrust Resumen El basamento Paleozoico que aflora al norte de Los Vilos está constituido por (i) el Complejo Metamórfico de Choapa (CMCh), formado por esquistos, cuarzo esquistos, gneises de grano fino y metabasitas (anfibolitas y retroeclogitas) y (ii) rocas metasedimentarias y sedimentarias de las formaciones Arrayán y Huentelauquén respectivamente. En los alrededores de Huentelauquén (31º 30' S), las rocas del CMCh han sido afectadas por tres fases de deformación (D1, D2, D3), relacionadas con el episodio orogénico Gondwánico. Las estructuras D1 están representadas por una foliación tectónica (S1), que se desarrolló bajo condiciones metamórficas de AP-BT y que está preservada en porfiroblastos de granate y albita, crecidos durante el segundo episodio de deformación. Durante la fase de deformación D2 se produce una bajada de la presión y se desarrolla la foliación regional S2. La foliación S2 es contemporánea con el emplazamiento de un dúplex de cabalgamientos dirigidos hacia el este que exhuman el CMCh y lo sitúan sobre las series epimetamórficas de la Formación Arrayán. El acortamiento que producen las estructuras D2 es superior a 20 km. La tercera fase de deformación está representada por pliegues y crenulaciones asociados a un antiforme de escala kilométric...

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Section: Introductionmentioning

confidence: 99%

Structure of the Andean Palaeozoic basement in the Chilean coast at 31º 30’ S: Geodynamic evolution of a subduction margin

Garcı́a-Sansegundo

Farias

Heredia

et al. 2014

Journal of Iberian Geology

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“…According to the age spectrum of detrital zircon, the maximum sedimentation age of the metasediments of the Guarguaraz Complex is about 563 Ma (Willner et al, 2008). Their peak PT-conditions were 13-14 kbar at about 500°C , which represent a metamorphic geotherm of close to 10°C/km during this metamorphic stage.…”

Section: Recent Palynological Studies In Western Patagonia Of Coyhaiqmentioning

confidence: 99%

“…Chilenia formed the back-stop system of the extensive Late Palaeozoic coastal accretionary system and was first covered by sediments of a wide Late Carboniferous retrowedge basin that also received detritus from the rising collisional belt (Guarguaraz Complex) and an Early Carboniferous magmatic arc (Willner et al, 2008).…”

Section: Mediciones De Gradiente De Campo Magnético En Un Campo De Exmentioning

confidence: 99%

International Lateinamerika-Kolloquium 2009

Möller-McNett¹

2009

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“…The upper intercept age suggests presence of inherited Neoproterozoic zircon. For metapelitic rocks comparable to the country rocks of the Cobquecura pluton, presence of Neoproterozoic detrital zircon is common for Coastal Central Chile (Willner et al, 2008).…”

Section: U-pb Data: Zircon Of a Metapelitic Xenolithmentioning

confidence: 99%

Origin of fayalite granitoids: New insights from the Cobquecura Pluton, Chile, and its metapelitic xenoliths

Vásquez¹,

Glodny²,

Franz³

et al. 2009

Lithos

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Fayalite granitoids of the Cobquecura Pluton, Central Chile, occur in an active continental margin setting, which is unusual for such rocks. They are closely associated with gabbros, and both lithologies contain hercynite-rich, Fe-rich metapelitic xenoliths. The primitive magmas of the Cobquecura Pluton are derived from a mafic source, similar to the regional subarc subcontinental mantle. Sr-Nd-Pb isotope data demonstrate that crustal contributions were important in the petrogenesis of the fayalite granitoids. The crustal contribution, however, does not consist of rocks similar to the regionally exposed Paleozoic basement rocks, but rather resembles partial melts derived from metapelitic rocks at depth. The corresponding restites are the hercynite-rich xenoliths. A relatively high content of rare earth elements and high field strength elements in the fayalite granitoids is linked to selective assimilation of crust. This is evident from the abundant xenoliths that are entrained in the fayalite granitoids, and whose leucosomes are rich in accessory minerals carrying these elements. Such Fe-rich rocks similar to the hercynite-rich xenoliths could have acted as a chemical buffer keeping the oxygen fugacity low, which is crucial for the generation of fayalite bearing granitoids.

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History of crustal growth and recycling at the Pacific convergent margin of South America at latitudes 29°–36° S revealed by a U–Pb and Lu–Hf isotope study of detrital zircon from late Paleozoic accretionary systems

Cited by 127 publications

References 46 publications

Structure of the Andean Palaeozoic basement in the Chilean coast at 31º 30’ S: Geodynamic evolution of a subduction margin

Structure of the Andean Palaeozoic basement in the Chilean coast at 31º 30’ S: Geodynamic evolution of a subduction margin

International Lateinamerika-Kolloquium 2009

Origin of fayalite granitoids: New insights from the Cobquecura Pluton, Chile, and its metapelitic xenoliths

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