%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Noury, M.
%A Bernet, M.
%A Schildgen, T. F.
%A Simon-Labric, T.
%A Philippon, M.
%A Sempéré, Thierry
%T Crustal-scale block tilting during Andean trench-parallel extension : structural and geo-thermochronological insights
%D 2016
%L fdi:010068281
%G ENG
%J Tectonics
%@ 0278-7407
%K Central Andes ; Peruvian fore arc ; thermochronology ; trench-parallel ; extension ; oroclinal bending
%K PEROU ; ANDES CENTRE
%M ISI:000385861300004
%N 9
%P 2052-2069
%R 10.1002/2016tc004231
%U https://www.documentation.ird.fr/hor/fdi:010068281
%> https://www.documentation.ird.fr/intranet/publi/2016/11/010068281.pdf
%V 35
%W Horizon (IRD)
%X Despite a long history of plate convergence at the western margin of the South American plate that has been ongoing since at least the Early Paleozoic, the southern Peruvian fore-arc displays little to no evidence of shortening. In the light of this observation, we assess the deformation history of the southern Peruvian fore-arc and its geodynamic implications. To accomplish this, we present a new structural and geo-thermochronological data set (zircon U-Pb, mica Ar-40/Ar-39, apatite and zircon fission-track and zircon (U-Th)/He analyses) for samples collected along a 400km long transect parallel to the trench. Our results show that the Mesoproterozoic gneissic basement was mainly at temperatures 350 degrees C since the Neoproterozoic and was later intruded by Jurassic volcanic arc plutons. Along the coast, a peculiar apatite fission-track age pattern, coupled with field observations and a synthesis of available geological maps, allows us to identify crustal-scale tilted blocks that span the coastal Peruvian fore-arc. These blocks, bounded by normal faults that are orthogonal to the trench, suggest post-60Ma trench-parallel extension that potentially accommodated oroclinal bending in this region. Block tilting is consistent with the observed and previously described switch in the location of sedimentary sources in the fore-arc basin. Our data set allows us to estimate the cumulative slip on these faults to be less than 2km and questions the large amount of trench-parallel extension suggested to have accommodated this bending.
%$ 064