Origin and evolution of the Precordillera terrane of western Argentina: A drifted Laurentian orphan

Astini, Ricardo A.; Thomas, William A.

doi:10.1130/0-8137-2336-1.1

Cited by 31 publications

(31 citation statements)

References 72 publications

(151 reference statements)

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“…[60] The Precordillera terrane is commonly accepted to have rifted from Laurentia in the Late Cambrian and to have remained as an isolated thermally subsiding passive margin until ∼470 Ma [Astini and Thomas, 1999;Benedetto et al, 1999] where the presence of Middle Ordovician K-bentonites [Huff et al, 1998;Fanning et al, 2004] and drowning of the carbonate platform [Astini and Thomas, 1999] are interpreted to mark its approach and initial accretion, respectively, to the Famatina margin. Mulcahy et al [2007] argued on the basis of a Cambrian (∼515 Ma) mylonite event in the hanging wall of the Las Pirquitas thrust that the Pie de Palo block could not be part the Precordillera, which lacks evidence of middle Cambrian deformation.…”

Section: Affinity Of the Sierra De Pie De Palomentioning

confidence: 99%

Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina

et al. 2011

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The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect reveals that the Sierra de Pie de Palo preserves a middle to lower crustal ductile thrust complex consisting of individual structural units and not an intact ophiolite and cover sequence. Top‐to‐the‐west thrusting occurred intermittently on discrete ductile shear zones from ∼515 to ∼417 Ma and generally propagated toward the foreland with progressive deformation. Ordovician crustal shortening and peak metamorphic temperatures in the central portion of the Sierra de Pie de Palo were synchronous with retro‐arc shortening and magmatic flare‐up within the Famatina arc. Accretion of the Precordillera terrane resulted in the end of arc flare‐up and the onset of synconvergent extension by ∼439 Ma. Continued synextensional to postextensional convergence was accommodated along progressively lower grade shear zones following terrane accretion and the establishment of a new plate margin west of the Precordillera terrane. The results support models of Cordilleran orogens that link voluminous arc magmatism to periods of regional shortening. The deformation, metamorphic, and magmatic history within the Sierra de Pie de Palo is consistent with models placing the region adjacent to the Famatina margin in the middle Cambrian and not as basement to the Precordillera terrane.

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Section: Affinity Of the Sierra De Pie De Palomentioning

confidence: 99%

Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina

et al. 2011

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“…1, Caminos 1979). This basement has registered the polyphase accretional history in the east of the Río de La Plata craton starting in the early Cambrian with the collision of the Pampean Terrane with the craton (Ramos et al 1986;Rapela et al 1998;Stuart-Smith et al 1999) followed by the amalgamation of the Precordillera/Cuyania Terrane to the newly formed margin of Gondwana during the Famatinian cycle (Astini and Thomas 1999;Rapalini et al 1999;Casquet et al 2001;Thomas et al 2002;Astini and Dávila 2004;Steenken et al 2006). The mode of emplacement of voluminous discordant granodioritic to syenogranitic batholiths throughout the Devonian is a matter of ongoing discussion.…”

Section: Geological Settingmentioning

confidence: 99%

The tectonic significance of K/Ar illite fine-fraction ages from the San Luis Formation (Eastern Sierras Pampeanas, Argentina)

Wemmer

Steenken²,

Müller

et al. 2011

Int J Earth Sci (Geol Rundsch)

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The Sierra de San Luis forms the southern tip of the Eastern Sierras Pampeanas in central Argentina. Two narrow belts of low-grade phyllites and quartz arenites, i.e. the San Luis Formation, have accommodated part of the strain-related differential exhumation of the medium-to high-grade metamorphic domains that constitute to the basement complex of the sierra. Eleven phyllite samples were subjected to the K/Ar fine-fraction dating technique. Results are interpreted in relation to the Kübler index of the illites, which indicate epimetamorphic conditions for the majority of the samples. Obtained ages between 330 and 290 Ma cover a period of compressional tectonics in the late Mississippian (Visean/Serpukhovian boundary) followed by the subsidence during the formation of the Paganzo Basin in the provinces of La Rioja and San Luis. These tectonic movements are coincident with the Toco orogeny in northern Chile and southern Bolivia. This suggests that the older K/Ar ages document the compressional stage and that younger ages record the cooling of the basement during the subsequent extensional uplift of the basement.

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“…The sandstone beds are in a thick sequence of basin-¢ll conglomerate that accumulated in fault-bounded basins. These basins developed atop the Precordillera carbonate platform as it broke apart and foundered in Mid to Late Ordovician time [7,11]. Astini and co-authors [1,7,11,12] interpret basin formation as a response to the docking of the Precordillera terrane with Gondwana in the early Mid Ordovician, which resulted in subsidence of a peripheral foreland basin and drowning of the carbonate platform, followed by post-collisional extension and considerable sediment progradation from the east.…”

Section: Las Vacasmentioning

confidence: 99%

Early Gondwanan connection for the Argentine Precordillera terrane

Finney

Gleason

Gehrels

et al. 2003

Earth and Planetary Science Letters

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The Precordillera of Argentina is widely accepted as an exotic terrane of Laurentian (North American) affinity. Newly acquired U/Pb ages on individual detrital zircons from Lower Cambrian and Upper Ordovician quartz sandstone beds in the Argentine Precordillera indicate a Gondwanan provenance not associated with any known part of Laurentia. Accordingly, the Precordillera terrane is likely underlain by basement rock of Gondwanan affinity. In addition, detrital zircons from the Upper Ordovician sandstone bed provide no evidence for a Mid Ordovician position against the inboard Famatina arc. These results demand critical re-evaluation of widely held assumptions regarding the paleogeography of the Argentine Precordillera. ß

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Origin and evolution of the Precordillera terrane of western Argentina: A drifted Laurentian orphan

Cited by 31 publications

References 72 publications

Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina

Structural evolution of a composite middle to lower crustal section: The Sierra de Pie de Palo, northwest Argentina

The tectonic significance of K/Ar illite fine-fraction ages from the San Luis Formation (Eastern Sierras Pampeanas, Argentina)

Early Gondwanan connection for the Argentine Precordillera terrane

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