Structure and tectonic evolution of the South Patagonian fold and thrust belt: Coupling between subduction dynamics, climate and tectonic deformation

GHIGLIONE, MATÍAS C.; ARAMENDÍA, INÉS; RONDA, GONZALO; SUÁREZ, RODRIGO J.

Andean Tectonics

Elsevier

Año: 2019; p. 675 - 697

This volume addresses the tectonic evolution of the Andes Mountains of South America. As the globaltype example of ocean-continent convergence, insights from the Andes are fundamental to understandingtectonic processes along subduction margins. Long-term evolution of this convergent plate boundaryspans tens to hundreds of millions of years, with sustained subduction of oceanic lithosphere of thePacific Ocean basin during Cenozoic, Mesozoic, and possibly late Paleozoic time.During subduction, the Andean margin has experienced varied tectonic regimes, including shortening,extension, and strike-slip deformation. This complex history can be linked to spatially andtemporally diverse plate tectonic configurations, with variations in relative convergence between thesubducting and overriding plate, shifts in the absolute motion of the South American plate toward thePacific Ocean basin, and changes in slab dip angle involving phases of shallow to flat-slab subductionand subsequent resteepening or breakoff of oceanic crustal/lithospheric materials.The main phase of Andean orogenesis has been concentrated in Cenozoic time. Principally eastwestshortening, crustal thickening, subduction-related magmatism, and deposition in forearc, hinterland,and foreland basins largely dictated the present topography of western South America. Andeantectonic processes are further influenced by deeper processes such as metamorphism (although thisrecord is rarely accessible within the Andes), and the surface processes of erosion and climate change.The interplay and feedback among such processes are on display in the Andes, where extreme variationsin erosion and climate offer opportunities to test geodynamic models of mountain building.This volume addresses a range of Andean tectonic provinces emblematic of Cordilleran orogenicbelts, which include a trench, variably developed accretionary prism, coastal forearc zone, well-knownmagmatic arc, and retroarc regions consisting of regionally important hinterland plateaus, a fold-thrustbelt, and foreland basin system. Individual chapters offer new results and integration with past studiesaddressing the tectonic processes involved in shaping the western margin of South America. Thesestudies span the entire Andes, and employ a range of techniques, including geophysics, structural geology,stratigraphy, sedimentology, petrology, geochronology, and thermochronology.