RT Journal Article
T1 The northern Patagonia Somuncura plateau basalts: a productof slab-induced, shallow asthenospheric upwelling?
A1 De Ignacio San José, Cristina
A1 Lópe, Iván
A1 Oyarzun Muñoz, Roberto
A1 Márquez González, Álvaro
AB The Meseta de Somuncura forms the largest basaltic plateau (20 000 km2 ) of southern Argentina (extra-Andean domain). Most of these tholeiitic to alkaline rocks were extruded at ~ 25 Ma (late Oligocene). The absence of rifting±thinning processes, plume activity, or slab-window phenomena leaves only one major possibility for the generation of Somuncura: asthenospheric ('OIB-like') corner flow leading to a transient thermal anomaly above the subducting plate. It is suggested herein that the intake of hot asthenosphere was forced into a favourable topography (concave-up) of the subducting plate, hen a major plate reorganization event (Farallon to Nazca)was taking place in late Oligocene to early Miocene time. The fast and vigorous intake of asthenosphere would have been induced by slab roll-back, leading to decoupling of the subducting plate. The Somuncura volcanic episode can be regarded as a marker of the passage from the extremelyoblique subduction of Farallon, to the birth of the Nazca plate and roughly perpendicular convergence between South America and Nazca.
PB John Wiley & Sons Limited
SN ISSN: 0954-4879, ESSN: 1365-3121
YR 2001
FD 2001
LK https://hdl.handle.net/20.500.14352/60261
UL https://hdl.handle.net/20.500.14352/60261
LA eng
DS Docta Complutense
RD 7 abr 2025