Paleomagnetic evidence of an early Paleozoic rotated terrane in northwest Argentina: A clue for Gondwana-Laurentia interaction?

Conti, C. M.; Rapalini, Augusto E.; Coira, Beatríz; Koukharsky, Magdalena María L.

doi:10.1130/0091-7613(1996)024<0953:peoaep>2.3.co;2

Cited by 46 publications

(68 citation statements)

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“…Earlier studies suggested that the Famatina Range represented a volcanic island arc [Aceñolaza and Toselli, 1984]. Paleomagnetic data [Conti et al, 1996;Rapalini et al, 1999] and biogeography [Benedetto and Sánchez, 1996;Benedetto, 1998] seem to favor the possibility of considering Famatina a paraautochthonous or allochthonous intraIapetus island arc system. Likewise, recent finding of low-latitude calcareous algae in the carbonates of the Volcancito Formation pose some doubt on the autochthony of the region by the latest Cambrian-earliest Tremadoc [Astini, 2001c].…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…Paleomagnetism is an excellent method to establish the paleolatitudinal position and former orientation of crustal blocks. Early Paleozoic paleomagnetic data from NW Argentina and N Chile have shown large systematic rotations with limited to no paleolatitude anomaly (Valencio et al 1980;Forsythe et al 1993;Conti et al 1996;Rapalini et al 1999Rapalini et al , 2002Rakotolofo 2004;Spagnuolo et al 2008;Spagnuolo 2009). These paleomagnetic poles were obtained in the Western Puna of Chile and Argentina, the Eastern Puna, the NW Pampean Ranges and the Famatina Ranges.…”

Section: Introductionmentioning

confidence: 94%

“…Published tectonic interpretations of these paleomagnetic results (Forsythe et al 1993;Conti et al 1996) proposed the opposite rotations of large para-authocthonous terranes (i.e. ccw for the Arequipa-Antofalla and cw for the Eastern Puna-Famatina) producing the closure of ocean floored backarc basins to the east and their subsequent accretion to the Gondwana margin ( Fig.…”

Section: Introductionmentioning

confidence: 98%

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Reinterpretation of the Ordovician rotations in NW Argentina and Northern Chile: a consequence of the Precordillera collision?

Spagnuolo

Rapalini²,

Astini

2010

Int J Earth Sci (Geol Rundsch)

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Early Paleozoic paleomagnetic data from NW Argentina and Northern Chile have shown large systematic rotations within two domains: one composed of the Western Puna that yields very large (up to 80°) counterclockwise rotations, and the other formed by the Famatina Ranges and the Eastern Puna that shows (*40°) clockwise rotations around vertical axes. In several locations, lack of significant rotations in younger rocks constrains this kinematic pattern to have occurred during the Paleozoic. Previous tectonic models have explained these rotations as indicative of rigid-body rotations of large para-autochthonous crustal blocks or terranes. A different but simple tectonic model that accounts for this pattern is presented in which rotations are associated to crustal shortening and tectonic escape due to the collision of the allochthonous terrane of Precordillera in the Late Ordovician. This collision should have generated dextral shear zones in the back arc region of the convergent SW Gondwana margin, where systematic domino-like clockwise rotations of small crustal blocks accommodate crustal shortening. The Western Puna block, bordering the Precordillera terrane to the north, might have rotated counterclockwise as an independent microplate due to tectonic escape processes, in a fashion similar to the present-day relationship between the Anatolia block and the Arabian microplate.

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“…[30] Early models for emplacement of the Famatinian arc depicted an outboard island arc that was accreted to western Gondwana during the Middle Ordovician [Conti et al, 1996;Toselli et al, 1996]. In contrast, described the Famatinian magmatic belt as a continental arc that intruded along the Gondwana margin, primarily on the basis of initial Sr ratios and Nd model ages.…”

Section: Early To Middle Ordovicianmentioning

confidence: 99%

Regional deformation of the Sierra de San Luis, Argentina: Implications for the Paleozoic development of western Gondwana

Whitmeyer

Simpson

2004

Tectonics

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Metamorphic and ductile deformation fabrics within the Sierra de San Luis, central Argentina, provide evidence for the Early to Middle Paleozoic development of the paleo‐Pacific margin of Gondwana. Presumed Vendian‐aged metasedimentary rocks within both the Sierra de San Luis and the Sierras de Córdoba preserve early pressure solution cleavage development. Cambrian peak metamorphism in the Sierras de Córdoba and Ordovician peak metamorphism in the Sierra de San Luis indicate that juxtaposition of these two terranes did not occur prior to the Late Ordovician. Peak metamorphism and regional folding of the Sierra de San Luis metasedimentary rocks is equated with early stages of the development and shortening of the Famatinian magmatic arc along the western margin of Gondwana. Extensive, NNE trending zones of upper greenschist‐ to amphibolite‐facies ductile deformation within the Sierra de San Luis and along the western margin of the Sierra de Comechingones record the dextral oblique juxtaposition of the Sierra de San Luis terrane against the southwestern margin of the Sierras de Córdoba, coincident with, or closely followed by, the suture of the exotic Precordillera terrane to the western margin of Gondwana by the Early Devonian. Middle to Late Devonian restricted, lower greenschist‐grade reactivation of ductile faults may record the accretion of the Chilenia terrane, the final stage of Paleozoic convergent tectonism along this segment of western Gondwana.

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Paleomagnetic evidence of an early Paleozoic rotated terrane in northwest Argentina: A clue for Gondwana-Laurentia interaction?

Cited by 46 publications

References 0 publications

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

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

Reinterpretation of the Ordovician rotations in NW Argentina and Northern Chile: a consequence of the Precordillera collision?

Regional deformation of the Sierra de San Luis, Argentina: Implications for the Paleozoic development of western Gondwana

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