Propagation of orographic barriers along an active range front: insights from sandstone petrography and detrital apatite fission-track thermochronology in the intramontane Angastaco basin, NW Argentina

摘要: The arid Puna plateau of the southern Central Andes is characterized by Cenozoic distributed shortening forming intramontane basins that are disconnected from humid foreland because defeat orogen-traversing channels. Thick Tertiary and Quaternary sedimentary fills in have reduced topographic contrasts between compressional ranges, leading to a typical low-relief morphology. Structurally identical still externally drained straddle eastern border document eastward propagation orographic barriers ensuing aridification. One them, Angastaco basin, transitional highly compartmentalized highlands undeformed Andean foreland. Sandstone petrography, structural stratigraphic analysis, combined with detrital apatite fission-track thermochronology ∼6200-m-thick Miocene Pliocene section late Eocene exhumation history source regions along (Eastern Cordillera (EC)) as well construction southeastern flank Andes. Onset EC time rapid Sierra de Luracatao (in EC) at about 20 Ma recorded sediments basin. Sediment accumulation basin began ∼15 Ma, which had already built sufficient topography prevent sourced detritus reaching After ∼13 Ma, shifted eastward, exhuming ranges preserve an partial annealing zone recording cooling during Cretaceous rifting event. Facies changes fossil content suggest after 9 Ma, constituted effective barrier prevented moisture penetration into plateau. Between 3.4 2.4 Ma, another was uplifted east, further aridification pronounced precipitation gradients mountain front. This study emphasizes important role tectonics evolution climate this part Andes.