EGU2020-9516, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-9516
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

What controls erosion (exhumation) along the humid eastern margin of the Northern Andes? Insights from U-Th/He thermochronology

Nicolas Perez-Consuegra1, Edward R Sobel2, Andres Mora3, Jose R Sandoval4, Paul G Fitzgerald1, Sebastian Zapata5, Mauricio Parra6, Johannes Glodny7, and Gregory D Hoke1
Nicolas Perez-Consuegra et al.
  • 1Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, United States of America (nperezco@syr.edu)
  • 2Institut für Geowissenschaften, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, Potsdam-Golm, 14476, Germany
  • 3Ecopetrol Brasil, Rio de Janeiro, Brazil
  • 4Instituto Colombiano del Petróleo, Piedecuesta, Santander, Colombia
  • 5Smithsonian Tropical Research Institute. Ancon, Panama
  • 6Institute of Energy and Environment, University of Sao Paulo, Av. Prof. Luciano Gualberto 1289, Cidade Universitaria, 05508-010, Sao Paulo, SP, Brazil
  • 7GFZ German Research Centre for Geosciences, Potsdam, Germany

The relative controls of rock uplift (tectonics) and precipitation (climate) on the exhumation of earth’s rocks in tectonically active mountain ranges are still debated. In low latitude tropical regions where rates of precipitation and the amount of vegetation cover are higher, more data is required to test the relative contribution of these factors to the evolution of orogenic topography. To contribute to this debate, cooling ages were derived for 25 bedrock and four detrital samples using the apatite (U-Th-Sm)/He (AHe) low temperature thermochronometer. AHe ages are reported along a ~450-km-wide swath on the eastern flank of the Northern Andes in Colombia (South America). The AHe cooling ages, that range from 2.5 Ma to 17 Ma, are compared to precipitation rates and geomorphic parameters in order to discern the relative importance of climate and/or tectonics on exhumation. Along the transect, AHe cooling ages are poorly correlated with the rates of precipitation but show a good correlation with landscape parameters such as average hillslope and average channel steepness. Moreover, young AHe cooling ages coincide with areas where deformation is mainly compressional; older AHe cooling ages are found in the middle part of the study area where strike-slip deformation dominates. The spatial distribution of the new AHe cooling ages suggests that in mountainous regions, in this case with high precipitation rates (> 1500 mm/yr), denudation is mainly controlled by the rate of vertical advection of material via tectonic processes. The spatial variations in precipitation may only have a second-order role in modulating exhumation rates.

How to cite: Perez-Consuegra, N., Sobel, E. R., Mora, A., Sandoval, J. R., Fitzgerald, P. G., Zapata, S., Parra, M., Glodny, J., and Hoke, G. D.: What controls erosion (exhumation) along the humid eastern margin of the Northern Andes? Insights from U-Th/He thermochronology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9516, https://doi.org/10.5194/egusphere-egu2020-9516, 2020