Plume overriding triggers shallow subduction and orogeny in the southern Central Andes

GIANNI, GUIDO M.; GARCÍA, HÉCTOR P.A.; LUPARI, MARIANELA; PESCE, AGUSTINA; FOLGUERA, ANDRÉS

GONDWANA RESEARCH

ELSEVIER SCIENCE BV

Año: 2017 vol. 49 p. 387 - 395

1342-937X

Plate tectonic theory implies that mantle plumes may be eventually overridden by lithosphere during continentaldrift. These events have particular tectonomagmatic consequences for active margins and hence relatedorogenic processes. Since the first documentation of plume overriding and the definition of the plume-modifiedorogeny concept, only few examples have been recognized in the geologic record. In this study, we analyzethe Neogene tectonic evolution of the Southern Central Andes between 35° and 38°S and its potentialrelation to the subduction of the Payenia plume as a recent analogue of this process. Through a series of tectonicreconstructions we show that progressive Payenia plume overriding correlates with Neogene arc-frontmigrations linked to slab shallowing, fold belt reactivation in the Main Cordillera and intraplate contractionin the San Rafael block. Additionally, Nazca slab tear determined from tomographic analyses and subsequentdiachronous steepening of the subducted plate may also be an aftermath of plume subduction as often describedin the final stages of plume-modified orogeny. Finally, we propose a modern analogue for processespreviously described, dating back to the Mesoproterozoic, which provides further insights into these complexsettings.