Evidencias de magmatismo precuyano (Pliensbachiano - Toarciano) en el norte de la Cordillera del Viento, provincia del Neuquén

caracterización geoquímica,isotópica e implicancias tectónicas

Translated title of the contribution: Evidence of precuyano (Pliensbachian–Toarcian) magmatism in northern Cordillera del Viento, Neuquén Province: geochemical, isotopic characterization and tectonic implications

Eduardo O. Zappettini, Silvia L. Lagorio, Marcelo Dalponte, Joao Orestes Santos, Elena Belousova

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The Precuyano cycle in northern Cordillera del Viento corresponds to a volcano-sedimentary sequence with U-Pb zircon SHRIMP ages between 187. 9 ± 1.8 and 181.2 ± 2.4 Ma (Pliensbachian to lower Toarcian). The lower section is predominantly basic to mesosilicic with few clastic and a distinctive jasper level. The upper section is volcanic, essentially of acidic nature. This sequence which is continental with records of restricted marine environment and represents the transition from sin-rift to post-rift stages, was assigned to the Colomichicó Formation and correlates with La Primavera and Milla Michicó Formations that crop out to the south of this mountain range. Magmatic zircons indicate a source with strong juvenile component of Neoproterozoic age and a subordinate component of recycled Mesoproterozoic crust. The inherited zircons suggest incorporation into the magma of crustal rocks with ages between Paleozoic and Archaean with mixed juvenile component and crustal recycling. Multi-elemental diagrams, together with La/Nb > 1, Ba/ Nb > 40, La/Ta > 25, Ba/La > 20 and Ta/Hf < 0.15 ratios prevailing for the basic to mesosilicic rocks characterize a magmatism generated in a volcanic arc, showing intraplate affinity (La/Ta < 25, Ta/Hf > 0.15 and Ba/La decrease) towards the top of the sequence. The interruption of the subduction that must have occurred at this latitude from Late Permian to late Early Jurassic according with diverse authors lead to explain this magmatism through melting by decompression of a mantle affected by metasomatism related to a previous subduction process.

Original languageSpanish
Pages (from-to)533-558
Number of pages26
JournalRevista de la Asociacion Geologica Argentina
Volume75
Issue number4
Publication statusPublished - 2018

Keywords

  • volcanismo bimodal
  • Pliensbachiano - Toarciano
  • Cordillera del Viento
  • Neuquén
  • bimodal volcanism
  • Pliensbachian–Toarcian

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