TY - JOUR A1 - Garcia, Victor H. A1 - Hongn, Fernando D. A1 - Yagupsky, Daniel A1 - Pingel, Heiko A1 - Kinnaird, Timothy A1 - Winocur, Diego A1 - Cristallini, Ernesto A1 - Robinson, Ruth Aj A1 - Strecker, Manfred T1 - Late Quaternary tectonics controlled by fault reactivation. Insights from a local transpressional system in the intermontane Lerma valley, Cordillera Oriental, NW Argentina JF - Journal of structural geology N2 - We analyzed the Lomas de Carabajal area in the intermontane Lerma valley of the Cordillera Oriental to assess the level of neotectonic activity in a densely populated region of northwestern Argentina. In this region, Plio-Pleistocene synorogenic conglomerates are deformed, locally associated with high-angle faults, and NNW-SSE oriented en-echelon folds characterized by wavelengths of < 1 km. The deformed Quaternary units follow the same pattern of deformation as observed in the underlying Neogene deposits; growth-strata geometries are observed near faults. This configuration is compatible with local left-lateral transpressional tectonism driven by ENE-WSW buttressing against the NW-oriented border of a Cretaceous extensional basin (Alemania sub-basin). Optically Stimulated Luminescence analysis of sandy-silty layers interbedded within the folded late Pleistocene conglomeratic sequence helps to determine uplift rates of 0.83-0.87 mm/a during the last 30-40 ka. Nearby the Lomas de Carabajal, a WNW-striking, 3-m-high fault scarp disrupts radiocarbon dated, 10-ka-old loessic deposits providing a Holocene mean uplift rate of 0.30 mm/a. Our data unambiguously show that shallow crustal deformation in the intermontane Lerma valley is ongoing; some of this deformation may be associated with seismicity. Our findings support the notion of temporally and spatially disparate deformation processes in the broken foreland of the northwestern Argentinean Andes. KW - Structural geology KW - Neotectonics KW - OSL and C-14 geochronology KW - Syntectonic sedimentation KW - Seismogenic sources Y1 - 2019 U6 - https://doi.org/10.1016/j.jsg.2019.103875 SN - 0191-8141 VL - 128 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Kirby, Eric A1 - Whipple, Kelin X. T1 - Expression of active tectonics in erosional landscapes JF - Journal of structural geology N2 - Understanding the manner and degree to which topography in active mountain ranges reflects deformation of the Earth's surface remains a first order goal of tectonic geomorphology. A substantial body of research in the past decade demonstrates that incising channel systems play a central role in setting relationships among topographic relief, differential rock uplift rate, and climatically modulated erosional efficiency. This review provides an introduction to the analysis and interpretation of channel profiles in erosional mountain ranges. We show that existing data support theoretical expectations of positive, monotonic relationships between channel steepness index, a measure of channel gradient normalized for downstream increases in drainage area, and erosion rate at equilibrium, and that the transient response to perturbations away from equilibrium engenders specific spatial patterns in channel profiles that can be used to infer aspects of the forcing. These aspects of channel behavior lay the foundation for a series of case studies that we use to illustrate how focused, quantitative analysis of channel morphology can provide insight into the spatial and temporal dynamics of active deformation. Although the complexities of river response to climate, lithology, and uplift patterns mean that multiple interpretations of topographic data alone will always possible, we show that application of stream profile analysis can be a powerful reconnaissance tool with which to interrogate the rates and patterns of deformation in active mountain belts. KW - Tectonic geomorphology KW - Active tectonics KW - River profiles KW - Neotectonics Y1 - 2012 U6 - https://doi.org/10.1016/j.jsg.2012.07.009 SN - 0191-8141 VL - 44 SP - 54 EP - 75 PB - Elsevier CY - Oxford ER -