Constraining neotectonic deformation of the Colombian sub-Andes

Abstract

The eastern foothills of the Eastern Cordillera of the Colombian Andes are actively shortening; however, deformation rates of Quaternary structures remain sparse. Here we present millennia-scale deformation rates of the Guaicaramo thrust in the Eastern Cordillera using Terrestrial in situ Cosmogenic Nuclide dating techniques. Furthermore, we analyze river profiles along strike using digital elevation models to quantify the fluvial response to uplift. This research provides insight into thrust wedge mechanics and dynamics, seismic hazard mitigation, and hydrocarbon production potential of the region. The Quaternary shortening rate of the Guaicaramo thrust is 1.72 ± 0.30 mm/yr, which represents ~3% of the total horizontal shortening across the Colombian Andes. Furthermore, the normalized channel steepness (ksn) values reflect that the Eastern Cordillera foothills are experiencing rapid uplift. Analysis of ksn is a novel approach in the region. This work provides quantitative metrics of the surface response to uplift along the eastern foothills of the Eastern Cordillera.