Geology and geochronology of the El Peñón granitic pluton: A contribution to the famatinian magmatic evolution in the Sierra de San Luis, Argentina

The El Peñón pluton is a peraluminous granite located in the northeastern sector of the Sierra de San Luis. According to its textural and mineral variations two endmember facies have been distinguished along it: a coarse-grained muscovite-bearing facies, and a fine-grained biotite-bearing facies. Fi...

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Bibliographic Details
Published in:	Journal of South American earth sciences Vol. 149; p. 105188
Main Authors:	Olsen, Daiana E., Morosini, Augusto F., Ortiz Suárez, Ariel E., Tibaldi, Alina M., Crespo, Esteban M.
Format:	Journal Article
Language:	English
Published:	Elsevier Ltd 01-12-2024
Subjects:	Famatinian back-arc setting Ordovician magmatism Peraluminous magmatism Sierras pampeanas orientales U-Pb zircon geochronology Sierras pampeanas orientales Peraluminous magmatism Ordovician magmatism U-Pb zircon geochronology Famatinian back-arc setting
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Summary:	The El Peñón pluton is a peraluminous granite located in the northeastern sector of the Sierra de San Luis. According to its textural and mineral variations two endmember facies have been distinguished along it: a coarse-grained muscovite-bearing facies, and a fine-grained biotite-bearing facies. Field relationships aligned with mineralogical and geochemical compositions, allow us to establish an anatectic origin for this pluton. Regarding the inherited zircon ages, the provenance area of the metasedimentary source could be linked to the orogenic systems of Western Gondwana. The analysis of the internal structure of the intrusive body related with the structural arrangement observed in the country rocks indicates a syn-kinematic emplacement of the igneous body with respect to the main deformational event described in the Sierra de San Luis, which has been assigned to the closure of the Famatinian arc. New U-Pb (LA-ICP-MS) zircon ages constrain the emplacement/crystallization age of the El Peñón granite within the time lapse between ∼470 and 460 Ma. The geochronological data presented here, together with geochemical and structural analysis, enables us to correlate the origin of the El Peñón pluton and the deformation that occurred during its emplacement with the Famatinian Orogeny. Thus, these results allow us to rule out the presence of Pampean magmatism in the Sierra de San Luis but also establish a new absolute age for the main deformational event of the range. •The El Peñón pluton is a peraluminous monzogranite of Middle Ordovician age.•The new U-Pb zircon age contradicts the previously determined Cambrian age.•The submagmatic to subsolidus fabrics occurred during a contractional event.•The main structuring of the area is attributed to the Famatinian Orogeny.
ISSN:	0895-9811
DOI:	10.1016/j.jsames.2024.105188