Famatinian inner arc: Petrographical observations and geochronological constraints on pegmatites and leucogranites of the Comechingones pegmatitic field (Sierras de Córdoba, Argentina)

Demartis, Manuel; Jung, Stefan; Berndt, Jasper; Aragón, Eugenio; Sato, Ana María; Radice, Stefania; Maffini, M. Natalia; Coniglio, Jorge E.; Insúa, Leonardo Alfredo Agulleiro

doi:10.1016/j.jsames.2017.08.010

Cited by 22 publications

(26 citation statements)

References 36 publications

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“…The GCSZ likely formed the basal thrust that controlled the widening of the orogen toward the forearc (Semenov & Weinberg, ). It was during the Famatinian Orogeny that the shear zone, located far in the foreland, developed into the >7.5‐km‐wide amphibolite facies thrust, active at high‐temperatures at 470 Ma (Demartis et al, ). We argue that the reactivation of older Pampean thrusts, like the GCSZ, led to the arc vergence of thrusts in the foreland of the Famatinian Orogeny.…”

Section: Discussionmentioning

confidence: 99%

“…• Table S1 • Table S2 • Table S3 • Table S4 • Table S5 • Table S6 • Table S7 constraints (Castro de Machuca et al, 2008;Demartis et al, 2017;Höckenreiner et al, 2003;.…”

Section: 1029/2018tc005417unclassified

“…The focus of this study is the Guacha Corral shear zone (GCSZ)-the most prominent thrust in the Sierra de Comechingones of Córdoba (e.g., Demartis et al, 2017;Martino, 2003;Martino et al, 1995;Otamendi et al, 1999Otamendi et al, , 2004Pinotti et al, 2006;Radice et al, 2018;Semenov & Weinberg, 2017;Whitmeyer & Simpson, 2003). Many researchers have reflected on the timing of metamorphism and deformation associated with the GCSZ based on data only indirectly related to it (e.g., Rapela et al, 1998a;Simpson et al, 2001;Sims et al, 1998).…”

Section: 1029/2018tc005417mentioning

confidence: 99%

“…Demartis et al () dated pegmatites and leucogranites from the very same Merlo section investigated by Steenken, López de Luchi, et al (). They found U‐Pb ages in zircon between 473.8 ± 3.9 and 474.8 ± 12.2 Ma suggesting coeval intrusion.…”

Section: Introductionmentioning

confidence: 98%

“…These shear zones are generally north‐south trending with reverse, top‐to‐west movement (e.g, Martino, ). While being reasonably well studied from a structural point of view, only some of these shear zones have robust geochronological constraints (Castro de Machuca et al, ; Demartis et al, ; Höckenreiner et al, ; Steenken, Wemmer, et al, ).…”

Section: Introductionmentioning

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: Discussionmentioning

confidence: 99%

“…• Table S1 • Table S2 • Table S3 • Table S4 • Table S5 • Table S6 • Table S7 constraints (Castro de Machuca et al, 2008;Demartis et al, 2017;Höckenreiner et al, 2003;.…”

Section: 1029/2018tc005417unclassified

Section: 1029/2018tc005417mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

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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Shear-assisted water-fluxed melting and AFC processes in the foreland of the Early Paleozoic Famatinian orogen: petrogenesis of leucogranites and pegmatites from the Sierras de Córdoba, Argentina

Demartis

Jung

Hauff

et al. 2021

Int J Earth Sci (Geol Rundsch)

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In the Comechingones pegmatitic field, central Argentina, leucogranite and pegmatite bodies crop out in a relatively narrow (25 × 10 km) belt, and were emplaced synkinematically with the main deformational event of the crustal-scale Guacha Corral shear zone during the Early Ordovician (~ 475 Ma). These leucogranites and pegmatites are geochemically evolved rocks with high silica and alkalis, low Fe 2 O 3 , MgO, TiO 2 and CaO, and high ASI values. The leucogranites display quite variable Sr and Nd isotope compositions (initial 87 Sr/ 86 Sr ratios from 0.7048 to 0.7170, and ε Nd values from + 2.0 to − 3.1), some of which do not overlap with almost any other pre-Famatinian rock from the Sierras de Córdoba. The major and trace element geochemistry and the particular Sr and Nd isotope compositions of the leucogranites are here explained by the following processes: (1) water-fluxed partial melting of amphibolites at relatively low P-T conditions generating currently unexposed granodioritic melts with unradiogenic 87 Sr/ 86 Sr ratios and radiogenic ε Nd values; (2) fractionation of mostly plagioclase and monazite leading to compositions close to the leucogranite melts; and (3) assimilation of metasedimentary rocks with crustal isotopic signatures, modelled by assimilation and fractional crystallization processes. The major, trace and isotope compositions of the pegmatites suggest a derivation from partial melting of the same metasedimentary protoliths of the Sierras de Córdoba that were assimilated by leucogranite melts. We propose a feedback relationship among deformation, anatexis, magma evolution and mass transfer in the context of such a crustal-scale shear zone in the foreland of the Famatinian orogen.

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Dioritic to granodioritic calc-alkaline magmatism in the Sierra de Comechingones southern tip, Córdoba, Argentina: tracking the Famatinian arc into the Pampean belt

Benito,

Tibaldi,

Cristofolini

et al. 2024

Int J Earth Sci (Geol Rundsch)

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Famatinian inner arc: Petrographical observations and geochronological constraints on pegmatites and leucogranites of the Comechingones pegmatitic field (Sierras de Córdoba, Argentina)

Cited by 22 publications

References 36 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

Shear-assisted water-fluxed melting and AFC processes in the foreland of the Early Paleozoic Famatinian orogen: petrogenesis of leucogranites and pegmatites from the Sierras de Córdoba, Argentina

Dioritic to granodioritic calc-alkaline magmatism in the Sierra de Comechingones southern tip, Córdoba, Argentina: tracking the Famatinian arc into the Pampean belt

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