Los primeros pulsos del magmatismo Varisco del NO de Iberia (Galicia, España). Datos preliminares de nuevas edades U-Pb SHRIMP y CA-ID-TIMS en granodioritas precoces

  1. L. González Menéndez 1
  2. G. Gallastegui 1
  3. A. Cuesta 2
  4. P. Montero 3
  5. P. Valverde-Vaquero 1
  6. A. Rubio-Ordóñez 2
  7. F. Bea 3
  1. 1 Instituto Geológico y Minero de España
    info

    Instituto Geológico y Minero de España

    Madrid, España

    ROR https://ror.org/04cadha73

  2. 2 Universidad de Oviedo
    info

    Universidad de Oviedo

    Oviedo, España

    ROR https://ror.org/006gksa02

  3. 3 Universidad de Granada
    info

    Universidad de Granada

    Granada, España

    ROR https://ror.org/04njjy449

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Revue:
Geotemas (Madrid)

ISSN: 1576-5172

Année de publication: 2021

Titre de la publication: X Congreso Geológico de España

Número: 18

Pages: 430

Type: Article

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D'autres publications dans: Geotemas (Madrid)

Résumé

Variscan granitoids from NW Iberia are grouped in pulses among which the early granodiorites are the focus of this report. Its geochemistry is mainly calc-alkaline and I-type. Relationships with mafic rocks are common. Its age was initially establi- shed in 349-350 Ma (whole-rock Rb-Sr and discordant zircon U-Pb TIMS; Gallastegui 2005). Afterwards, U-Pb zircon dating by ID-TIMS gave younger concordant ages (318-323 Ma; Rodríguez et al., 2007). More recent zircon dating by LA-ICP-MS returned to older ages (337-347 Ma; Gutiérrez-Alonso et al., 2018). In order to solve these discrepancies we have made SHRIMP and CA-ID-TIMS zircon dating in granodiorites where contradictory ages had been obtained. Our results show concordant 315-326 Ma ages, coincident with the younger phases for this magmatism. Field relations with syntectonic S-type granites (318-320 Ma) support these younger ages.

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