Petrogenesis of the Eocene and Mio-Pliocene alkaline basaltic magmatism in Meseta Chile Chico, southern Patagonia, Chile: Evidence for the participation of two slab windows

Felipe Espinoza, Diego Morata, Ewan Pelleter, René C. Maury, Manuel Suárez, Yves Lagabrielle, Mireille Polvé, Hervé Bellon, Joseph Cotten, Rita De la Cruz, Christelle Guivel

Resultado de la investigación: Contribución a una revistaArtículo

56 Citas (Scopus)

Resumen

The Meseta Chile Chico (MCC, 46.4°S) is the westernmost exposure of Eocene (lower basaltic sequence, LBS; 55-40 Ma, K-Ar ages) and Mio-Pliocene (upper basaltic sequence, UBS; 16-4 Ma, K-Ar ages) flood basalt volcanism in Patagonia. The MCC is located south of the Lago General Carrera-Buenos Aires (LGCBA), southeast from the present day Chile Triple Junction (CTJ), east of the actual volcanic gap between Southern South Volcanic Zone and Austral Volcanic Zone (SSVZ and AVZ, respectively) and just above the inferred location of the South Chile Ridge segment subducted at ∼6 Ma (SCR-1). Erupted products consist of mainly ne-normative olivine basalt with minor hy-normative tholeiites basalt, trachybasalt and basanite. MCC lavas are alkaline (42.7-53.1 wt.% SiO2, 3-8 wt.% Na2O+K2O) and relatively primitive (Ni: 133-360 ppm, Cr: 161-193 ppm, Co: 35-72 ppm, 4-16.5 MgO wt.%). They have a marked OIB-like signature, as shown by their isotopic compositions (87Sr/86Sro =0.70311-0.70414 and εNd=+4.7-+5.1) and their incompatible trace elements ratios (Ba/La=10-20, La/Nb=0.46-1.09, Ce/Pb=15.52-27.5, Sr/La<25), reflecting deep mantle origin. UBS-primitive lavas have characteristics similar to those of the Eocene LBS basalts, while UBS-intermediate lavas show geochemical imprints (La/Nb>1, Sr/La>25, low Ce/Pb, Nb/U) compatible with contamination by arc/slab-derived and/or crustal components. We propose that the genesis and extrusion of magmas is related to the opening of two slab windows due to the subduction of two active ridge segments beneath Patagonia during Eocene and Mio-Pliocene.

Idioma originalInglés
Páginas (desde-hasta)315-343
Número de páginas29
PublicaciónLithos
Volumen82
N.º3-4 SPEC. ISS.
DOI
EstadoPublicada - 1 jun 2005

Áreas temáticas de ASJC Scopus

  • Geoquímica y petrología

Huella Profundice en los temas de investigación de 'Petrogenesis of the Eocene and Mio-Pliocene alkaline basaltic magmatism in Meseta Chile Chico, southern Patagonia, Chile: Evidence for the participation of two slab windows'. En conjunto forman una huella única.

  • Citar esto

    Espinoza, F., Morata, D., Pelleter, E., Maury, R. C., Suárez, M., Lagabrielle, Y., Polvé, M., Bellon, H., Cotten, J., De la Cruz, R., & Guivel, C. (2005). Petrogenesis of the Eocene and Mio-Pliocene alkaline basaltic magmatism in Meseta Chile Chico, southern Patagonia, Chile: Evidence for the participation of two slab windows. Lithos, 82(3-4 SPEC. ISS.), 315-343. https://doi.org/10.1016/j.lithos.2004.09.024