We present field and seismic evidence for the existence of Coniacian-Campanian syntectonic angular unconformities within basal foreland basin sequences of the Austral or Magallanes Basin, with implications for the understanding of deformation and sedimentation in the southern Patagonian Andes. The studied sequences belong to the mainly turbiditic Upper Cretaceous Cerro Toro Formation that includes a world-class example of conglomerate-filled deep-water channel bodies deposited in an axial foredeep depocenter.We present multiple evidence of syntectonic deposition showing that the present internal domain of the fold-thrust belt was an active Coniacian-Campanian wedge-top depozone where deposition of turbidites and conglomerate channels of Cerro Toro took place.

Contraction in intraplate areas is still poorly understood relative to similar deformation at plate margins. In order to contribute to its comprehension, we study the Patagonian broken foreland (PBF) in South America whose evolution remains controversial. Time constraints of tectonic events and structural characterization of this belt are limited. Also, major causes of strain location in this orogen far from the plate margin are enigmatic. To unravel tectonic events, we studied the Cenozoic sedimentary record of the central sector of the Patagonian broken foreland (San Bernardo fold and thrust belt, 44º30'S-46ºS) and the Andes (Meseta de Chalia,46ºS) following an approach involving growth-strata detection, U-Pb geochronology and structural modeling. Additionally, we elaborate a high resolution analysis of the effective elastic thickness (Te) to examine the relation between intraplate contraction location and zones of low lithospheric strength. The occurrence of Eocene growth-strata (~44-40 Ma) suggests that

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