TY - JOUR
T1 - How erosional efficiency modulates landscape response to drainage reorganization
T2 - New empirical evidence from the Andes
AU - García-Delgado, Helbert
AU - Schwanghart, Wolfgang
AU - Hoke, Gregory D.
AU - Guerrero, Benjamin
AU - Velandia, Francisco
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/11/1
Y1 - 2023/11/1
N2 - The fluvial network in active mountain ranges is considered to evolve from longitudinal to transverse-dominated drainage systems. This hypothesis links to the forelandward migration of the orogen, while crustal thickening modifies the range's flank slopes, enhancing erosional efficiency. We probe such a proposition with new empirical observations from the Colombian Andes by studying the recent capture of the longitudinal Suárez and Chicamocha Rivers by the transverse Sogamoso River. Firstly, by integrating published low-temperature thermochronology and quantitative topographic metrics like χ, we found that rejuvenated rock uplift in the Cocuy and Yariguies ranges delays the transition from longitudinal to transverse-dominated drainage systems by compensating the across-divide contrasts in erosion. To further constrain the spatiotemporal response of the Suárez and Chicamocha Rivers after the discrete capture, we computed sediment-gauge erosion rates in conjunction with rainfall-normalized channel steepness and Gilbert metrics. We observe stark contrasts in erosion rates between the Chicamocha (maximum of 148.22 ± 44.86 m/Myr) and Suárez Rivers (maximum of 71.9 ± 21.5 m/Myr). Higher erosion rates in the former are expressed with widely distributed slope-break knickpoints that migrated further upstream with catchment expansion at the expense of the less efficiently erosive Suárez River basin. We interpret these erosional differences as a lithological control on the pace of topographic response to an external perturbation (discrete capture), given low-lying sedimentary rocks delay the erosional response of the Suárez River basin. Our research therefore emphasizes the role that lithology poses in keeping the landscape in an unsteady topographic condition.
AB - The fluvial network in active mountain ranges is considered to evolve from longitudinal to transverse-dominated drainage systems. This hypothesis links to the forelandward migration of the orogen, while crustal thickening modifies the range's flank slopes, enhancing erosional efficiency. We probe such a proposition with new empirical observations from the Colombian Andes by studying the recent capture of the longitudinal Suárez and Chicamocha Rivers by the transverse Sogamoso River. Firstly, by integrating published low-temperature thermochronology and quantitative topographic metrics like χ, we found that rejuvenated rock uplift in the Cocuy and Yariguies ranges delays the transition from longitudinal to transverse-dominated drainage systems by compensating the across-divide contrasts in erosion. To further constrain the spatiotemporal response of the Suárez and Chicamocha Rivers after the discrete capture, we computed sediment-gauge erosion rates in conjunction with rainfall-normalized channel steepness and Gilbert metrics. We observe stark contrasts in erosion rates between the Chicamocha (maximum of 148.22 ± 44.86 m/Myr) and Suárez Rivers (maximum of 71.9 ± 21.5 m/Myr). Higher erosion rates in the former are expressed with widely distributed slope-break knickpoints that migrated further upstream with catchment expansion at the expense of the less efficiently erosive Suárez River basin. We interpret these erosional differences as a lithological control on the pace of topographic response to an external perturbation (discrete capture), given low-lying sedimentary rocks delay the erosional response of the Suárez River basin. Our research therefore emphasizes the role that lithology poses in keeping the landscape in an unsteady topographic condition.
KW - Andes
KW - Knickpoints
KW - Landscape evolution
KW - River capture
KW - Stream power model
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U2 - 10.1016/j.geomorph.2023.108893
DO - 10.1016/j.geomorph.2023.108893
M3 - Article
AN - SCOPUS:85169805573
SN - 0169-555X
VL - 440
JO - Geomorphology
JF - Geomorphology
M1 - 108893
ER -