A Middle Paleozoic shear zone in the Sierra de Valle Fértil, Argentina: Records of a continent-arc collision in the Famatinian margin of Gondwana

Cristofolini, Eber A.; Otamendi, Juan E.; Walker, B. A.; Tibaldi, A; Armas, Paula; Bergantz, George W.; Martino, Roberto

doi:10.1016/j.jsames.2014.09.010

Cited by 30 publications

(26 citation statements)

References 71 publications

(166 reference statements)

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“…Our Ar isotope investigation suggests that the background cooling rates across the 400–300 °C isotherms for the GCSZ (Figure ) were in the slow cooling range of <10 °C/Ma, such as inferred for the Silurian/Devonian transition (Cristofolini et al, ). Slow cooling was accelerated by the two shearing events recorded here.…”

Section: Discussionsupporting

confidence: 63%

“…A biotite 40 Ar/ 39 Ar age from a mylonite in the Sierra del Valle Fertil yielded a plateau age of 409 ± 2 Ma, interpreted as marking cooling below 315 ± 30 °C (Cristofolini et al, ). This age was integrated with the 440 ± 5‐Ma Ar‐cooling age of amphiboles from the neighboring Sierra de la Huerta (Castro de Machuca et al, ) to derive cooling rates between “4 and 9 °C/Ma over a time spanning the Silurian/Devonian transition” (Cristofolini et al, ).…”

Section: Geology Of the Sierra De Comechingones And The Gcszmentioning

confidence: 99%

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Prolonged Movement on a > 10‐km‐Wide Thrust During Early Paleozoic Orogens in the Gondwana Margin of NW Argentina

et al. 2019

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The >10‐km thick Paleozoic Guacha Corral shear zone in Central Argentina is arguably one of the thickest thrust zones anywhere. It played a key role during the two early Paleozoic orogenies of western Gondwana and currently separates two terranes: one dominated by events related to the >510‐Ma Pampean Orogeny and the other by the <500‐Ma events of the Famatinian Orogeny. The combination of structures and geochronometry suggests that the shear zone was active for over 100 Ma. Thrusting started during migmatization at 520 Ma as recorded by U‐Pb ages in zircon and monazite and was demonstrably active also at 480 and 470 Ma. The age coincidence between Ar plateau ages of muscovite and biotite at 420 Ma in the upper part of the shear zone, and at 405 Ma in the lower part suggests two intense cooling pulses. These are ascribed to thrusting, rapid exhumation, and cooling. Its anomalous width is likely a result of this prolonged kinematic history related to its role in transferring shortening to the Pampean forearc possibly as a basal detachment and later by acting as the main boundary between the Pampean and Famatinian tectonometamorphic terranes. The two low‐temperature shearing events inferred from the Ar ages suggest that deformation continued during the period between the end of the Famatinian cycle at ~440 Ma and the start of the Chanic or Achalian Orogeny and its magmatism after 400 Ma.

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Section: Discussionsupporting

confidence: 63%

Section: Geology Of the Sierra De Comechingones And The Gcszmentioning

confidence: 99%

Prolonged Movement on a > 10‐km‐Wide Thrust During Early Paleozoic Orogens in the Gondwana Margin of NW Argentina

et al. 2019

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“…The backarc was dominated initially by an extensional tectonic regime with the development of marine sedimentary basins between ~485 and 470 Ma (Astini, 2008; Bahlburg & Breitkreuz, 1991; Bahlburg & Hervé, 1997b; Büttner, 2009; Moya, 2015; Rapela et al, 2018). Deformation in the backarc switched to shortening after ~470 Ma (Weinberg et al, 2018), starting the event known as the Oclóyic phase (Cristofolini et al, 2014; Otamendi et al, 2020; Turner, 1975). This event was triggered by the arrival and docking of the Laurentian‐derived Precordillera/Cuyania block to the western margin of Gondwana and marked by regional unconformities formed during the inversion of the basins (Astini & Dávila, 2004; Bahlburg & Hervé, 1997a; Davila et al, 2003; Ramos, 2008; Thomas & Astini, 2003).…”

Section: Regional Geologymentioning

confidence: 99%

“…This event was triggered by the arrival and docking of the Laurentian‐derived Precordillera/Cuyania block to the western margin of Gondwana and marked by regional unconformities formed during the inversion of the basins (Astini & Dávila, 2004; Bahlburg & Hervé, 1997a; Davila et al, 2003; Ramos, 2008; Thomas & Astini, 2003). This phase was characterized by folding and development of several wide thrusts at midcrustal levels (Cristofolini et al, 2014; Finch et al, 2015; Larrovere et al, 2016, 2011; Rapela, Pankhurst, Casquet, et al, 1998; Semenov et al, 2019; Semenov & Weinberg, 2017). The Famatinian orogenic cycle is inferred to have finished at around 440–435 Ma when magmatism waned (2009; Bahlburg et al, 2016; Büttner et al, 2005; Mulcahy et al, 2014; Wolfram et al, 2017).…”

Section: Regional Geologymentioning

confidence: 99%

From Crustal Thickening to Orogen‐Parallel Escape: The 120‐Myr‐Long HT‐LP Evolution Recorded by Titanite in the Paleozoic Famatinian Backarc, NW Argentina

et al. 2020

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Exposed sections of accretionary orogens allow reconstruction of their tectonic evolution. Most commonly, orogens are characterized by two-dimensional shortening perpendicular to the orogenic front. We describe the midcrustal section of the backarc of the early Paleozoic Famatinian accretionary orogen, exposed in the Sierra de Quilmes. Here crustal deformation evolved from a typical two-dimensional shortening with tectonic transport toward the west, to a noncoaxial constrictional strain with a southward tectonic transport parallel to the orogen. During the early phase of deformation, high-temperature and low-pressure (HT-LP) metamorphic complexes were juxtaposed by west directed thrusting on remarkably thick shear zones forming a thrust duplex. Deformation of the buried footwall complex continued after the exhumed hanging wall ceased to deform. We suggest that the thermally weakened footwall complex responded by initiating a phase of south verging thrusting, parallel to the orogen, associated with strong constriction, associated with L-tectonites, and sheath folds. This late phase of deformation defines a noncoaxial constrictional regime characterized by simultaneous east-west and vertical shortening and strong north-south, orogen-parallel stretching. Titanite ages and Zr-in-titanite thermometry demonstrate that this backarc remained above 700°C for 120 Myr between 500 and 380 Ma. Combined with regional geology, the new data suggest that west verging thrusting interrupted an early, back-arc extensional phase, and lasted from~470 to 440 Ma and that footwall constriction and south verging thrusting continued for another 40 to 60 Ma. The Famatinian backarc exposed in Sierra de Quilmes thus is an example of how shortening and orogenic growth in a hot orogen was counterbalanced by lateral flow.

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“…1 y 10), se puede apoyar su probable correlación genética-temporal. Esto último afianzado también en el hecho de que tanto en la Sierra Grande de San Luis como en La Aguada, las rocas plutónicas son afectadas por fajas de cizalla localizadas, las cuales se vincularían a la fase final de la orogenia Famatiniana, posiblemente asociadas al estadío colisional del terreno Cuyania/ Precordillera sobre el proto-margen de Gondwana (Ordovícico superior-Silúrico; ver Sato et al, 2003Cristofolini et al, 2014). Por lo tanto, la edad del magmatismo estudiado en este trabajo, es por lo menos anterior a dichas zonas de cizalla e indica que las rocas plutónicas de ambas serranías podrían tener una relación temporal afín.…”

Section: Correlación Entre El Magmatismo De La Sierra De La Aguada Y unclassified

Caracterización petrológica y geoquímica de las rocas plutónicas de la Sierra de La Aguada, Provincia de San Luis, Argentina: Implicaciones genéticas con el arco magmático Famatiniano

et al. 2017

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El presente trabajo expone una síntesis de la geología que comprende al complejo cristalino que constituye la Sierra de La Aguada, provincia de San Luis, Argentina, desde un enfoque basado en las relaciones de campo, los rasgos petrológico-estructurales y las características geoquímicas. Dicha serranía expone un basamento dominado por rocas plutónicas intermedias-máficas de afinidad calcoalcalina y granitoides félsicos peraluminosos, en conjunto intruidas en metamorfitas de bajo a medio grado metamórfico estabilizadas en condiciones de facies de anfibolita. Todo el conjunto litológico ha sido agrupado dentro del denominado complejo El Carrizal-La Aguada. El análisis de las relaciones de campo, la petrografía y la comparación de las características geoquímicas de las rocas plutónicas del área estudiada y aquellas pertenecientes a la suite ordovícica Famatiniana expuestas en la Sierra Grande de San Luis, sugiere una posible relación genética-temporal vinculada al desarrollo del arco magmático Famatiniano.

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A Middle Paleozoic shear zone in the Sierra de Valle Fértil, Argentina: Records of a continent-arc collision in the Famatinian margin of Gondwana

Cited by 30 publications

References 71 publications

Prolonged Movement on a > 10‐km‐Wide Thrust During Early Paleozoic Orogens in the Gondwana Margin of NW Argentina

Prolonged Movement on a > 10‐km‐Wide Thrust During Early Paleozoic Orogens in the Gondwana Margin of NW Argentina

From Crustal Thickening to Orogen‐Parallel Escape: The 120‐Myr‐Long HT‐LP Evolution Recorded by Titanite in the Paleozoic Famatinian Backarc, NW Argentina

Caracterización petrológica y geoquímica de las rocas plutónicas de la Sierra de La Aguada, Provincia de San Luis, Argentina: Implicaciones genéticas con el arco magmático Famatiniano

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