(Un)Coupled thrust belt-foreland deformation in the northern Patagonian Andes: New insights from the Esquel-Gastre sector (41°30'-43°S) - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Tectonics Year : 2016

(Un)Coupled thrust belt-foreland deformation in the northern Patagonian Andes: New insights from the Esquel-Gastre sector (41°30'-43°S)

E. Savignano
  • Function : Author
S. Mazzoli
  • Function : Author
M. Arce
  • Function : Author
M. Franchini
  • Function : Author
M. Paolini
  • Function : Author
M. Zattin
  • Function : Author

Abstract

The Patagonian Andes represents a unique natural laboratory to study surface deformation in relation to deep slab dynamics. In the sector comprised between latitudes 41°30' and 43°S, new apatite (U-Th)/He ages indicate a markedly different unroofing pattern between the "broken foreland" area (characterized by Late Cretaceous to Paleogene exhumation) and the adjacent Andean sector to the west, which is dominated by Miocene-Pliocene exhumation. These unroofing stages can be confidently ascribed to inversion tectonics involving reverse fault-related uplift and concomitant erosion. Late Cretaceous-Paleogene shortening and exhumation are well known to have affected also the thrust belt sector of the study area during a prolonged stage of flat-slab subduction. Therefore, the different ages of near-surface unroofing documented in this study suggest coupling of the deformation between the thrust belt and its foreland during periods of flat-slab subduction (e.g., during Late Cretaceous-Paleogene times) and dominant uncoupling during periods of steep-slab subduction and rollback, even when these are associated with high convergence rates (i.e., > 4 cm/yr), as those documented in Miocene times for the Patagonian Andes.
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insu-03745247 , version 1 (04-08-2022)

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E. Savignano, S. Mazzoli, M. Arce, M. Franchini, C. Gautheron, et al.. (Un)Coupled thrust belt-foreland deformation in the northern Patagonian Andes: New insights from the Esquel-Gastre sector (41°30'-43°S). Tectonics, 2016, 35, pp.2636-2656. ⟨10.1002/2016TC004225⟩. ⟨insu-03745247⟩
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