Título:
Isotopic features (Sr-Nd) of the Pepe Núñez Alkaline Suite (Late Cretaceuos to Cenozoic) in the southern extreme of the Paraná Basin (NW Uruguay)
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Autor:
Olivera Ichazo, Lucía
Muzio Sauer, Rossana
Peel Canabal, Elena
Suárez, Marcos
Fort, Santiago
Muzio Sauer, Rossana
Peel Canabal, Elena
Suárez, Marcos
Fort, Santiago
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Tipo de documento:
Ponencia
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Palabras clave:
Alkaline plugs
Sr-Nd isotopes
Norte Basin
Sr-Nd isotopes
Norte Basin
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Año de publicación:
2026
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Resumen:
The Pepe Núñez alkaline suite represents the first record of subvolcanic rocks of alkaline affinity in the Norte Basin (southern extreme of the Paraná Basin, Uruguay) [1]. These Late Cretaceous to Cenozoic occurrences comprise nine subvolcanic plugs (Ne-tephrites, alkali trachybasalts, and alkali basalts) that cross-cut the tholeiitic basaltic pile of the Paraná Magmatic Province [2]. This work presents Sr-Nd isotopic data from 30 representative samples to characterize their petrogenesis. Analyses were performed by TIMS (Sr) and ICP-MS (Nd). Initial 87Sr/86Sr (Sri) ratios range from 0.7038 to 0.7044, εNd(i) values range from -0.17 to +1.54. Depleted mantle model ages (TDM) vary between 663 Ma and 885 Ma. Geochemically, the samples form a tight cluster plotting within the Mantle Array, overlapping with the OIB (Ocean Island Basalts) field. Notably, the isotopic signature of these alkaline rocks is clearly distinct from the Low-Ti basalts of the Paraná Magmatic Province, showing no evidence of the significant crustal contamination typically observed in the tholeiitic sequences. The Ne-tephrites show slightly more depleted signatures (εNd(i)= +0.73 to +1.54) compared to the alkali basalts and trachybasalts (εNd(i)= -0.17 to +1.08). The data suggest that the Pepe Núñez Alkaline Suite originated from a mantle source with OIB-like affinity (resembling FOZO-PREMA, or metasomatized SCLM), likely related to partial melting of metasomatized lithospheric mantle or asthenospheric components that ascended rapidly, avoiding interaction with the continental crust.
Descripción:
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SUG
EN:
XIV SSAGI, Montevideo - Uruguay, 13-16 abril 2026
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ANII: POS_FCE_2023_1_1011925
Citación:
Olivera Ichazo, L, Muzio Sauer, R, Peel Canabal, E, [y otros autores] "Isotopic features (Sr-Nd) of the Pepe Núñez Alkaline Suite (Late Cretaceuos to Cenozoic) in the southern extreme of the Paraná Basin (NW Uruguay)". [en línea] EN: XIV SSAGI, Montevideo - Uruguay, 13-16 abril 2026. 1 h.
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Cobertura geográfica:
Uruguay
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Licencia:
Licencia Creative Commons Atribución - No Comercial - Sin Derivadas (CC - By-NC-ND 4.0)
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| Ficheros | Descripción | Tamaño | Formato | ||
|---|---|---|---|---|---|
| SSAGI2026.pdf | — | 183.02 KB | Adobe PDF |