Deformation, age, and provenance of the Nogolí Metamorphic Complex protoliths, Sierra de San Luis, Argentina: evidence of a non-collisional history for the Cambrian in the western Gondwana margin

Deformation, age, and provenance of the Nogolí Metamorphic Complex protoliths, Sierra de San Luis, Argentina: evidence of a non-collisional history for the Cambrian in the western Gondwana margin

Situated in the western Sierras Pampeanas of San Luis, the Nogolí Metamorphic Complex has become a key geological locality for unraveling the construction of the western Gondwana margin on the South American tectonic plate. This study presents a comprehensive analysis, encompassing new petrological...

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Bibliographic Details
Published in:International journal of earth sciences : Geologische Rundschau Vol. 113; no. 1; pp. 185 - 206
Main Authors: Morosini, Augusto F., Enriquez, Eliel, Tibaldi, Alina M., Perón Orrillo, Juan M., Cristofolini, Eber A., Manchento, Damián A., Pagano, Diego S., Carugno Duran, Andrés O., Schwartz, Joshua J., Otamendi, Juan E., Ortiz Suárez, Ariel E.
Format: Journal Article
Language:English
Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2024
Springer Nature B.V
Subjects:
Age
Age composition
Cambrian
Chronology
Deformation
Earth and Environmental Science
Earth Sciences
Geochemistry
Geochronology
Geology
Geophysics/Geodesy
Gondwana
Mineral Resources
Original Paper
Orogeny
Plate tectonics
Plates (tectonics)
Provenance
Radiometric dating
Schist
Schists
Sedimentology
Structural Geology
Zircon
Gondwana
Famatinian orogeny
Petrology
Structure
Detrital zircon ages
Eastern Pampean Ranges
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Summary:Situated in the western Sierras Pampeanas of San Luis, the Nogolí Metamorphic Complex has become a key geological locality for unraveling the construction of the western Gondwana margin on the South American tectonic plate. This study presents a comprehensive analysis, encompassing new petrological and geochronological data, along with a meticulous structural examination of two distinct regions within the Nogolí Metamorphic Complex. Our primary aim is to assess the age and provenance of the protoliths, thereby shedding light on their geodynamic evolution. Detrital zircon U–Pb ages, obtained from a quartz–feldspathic-schist paleosome within a metatexite exposure in the La Barranquita area, disclosed a polymodal distribution. The predominant age population, centered around 616 ± 11 Ma, suggests a late Neoproterozoic source (Brasiliano–Pan African orogen). A secondary, yet significant, age peak at 542 ± 12 Ma points to a late Ediacaran to Early Cambrian origin (Pampean orogen). Additionally, a peak ranging from 930 to 1144 Ma indicates contributions from an early Neoproterozoic source (Grenvillian–Sunsas orogen). The maximum depositional age was determined to be 533 ± 14 Ma, based on the calculation of the youngest grain cluster at 2σ uncertainty. This polymodal zircon-age spectrum indicates that the sedimentary protolith of the Nogolí Metamorphic Complex derived from a Cambrian-age crystalline basement situated along the western margin of Gondwana. Contrary to models invoking continent–continent collision in western Gondwana during the early Cambrian, our findings better support a ridge–trench collision as the most plausible hypothesis for the origin of the Pampean orogeny. Graphical abstract
ISSN:1437-3254
1437-3262
DOI:10.1007/s00531-023-02366-7