Middle Miocene calc-alkaline volcanism in Central Patagonia (47°S): petrogenesis and implications for slab dynamics

Research areas:
Year:
2010
Authors:
  • Felipe Espinoza
  • Diego Morata
  • Mireille Polve
  • Yves Lagabrielle
  • Rene C. Maury
  • Aude de la Rupelle
  • Christèle Guivel
  • Joseph Cotten
  • Herve Bellon
  • Manuel Suarez
Journal:
ANDEAN GEOLOGY
Volume:
37
Number:
2
Pages:
300-328
Month:
July
ISSN:
0718-7106
Abstract:
We present a chronological (K-Ar), petrologic and geochemical study (major and trace elements, Sr-Nd isotopes) of Middle Miocene (ca. 16-14 Ma) calc-alkaline rocks (basalts to andesites) extruded in the present-day back-arc region of Central Patagonia (Zeballos Volcanic Sequence (ZVS), 47 S). This magmatism started shortly after mafic plutonism ceased in the arc region (ca. 16 Ma, 200 km west), and ended ca. 2 My before the onset of voluminous slab tear-related back-arc alkaline basaltic magmatism (ca. 12 to Pliocene). The studied calc-alkaline rocks have a typical subduction-related signature (high LILE/HFSE ratios, depletion in Nb, Ta and Ti; Ba/La >20; Ta/Hf e Neogene Patagonian Plateau Lavas province.