Cenozoic landscape evolution of the Kruger National Park as derived from cosmogenic nuclide analyses

Abstract

In contrast to active tectonic settings, little is known about the potential feedback between surface processes and climate change in tectonically inactive cratonic regions. Here, we studied the driving forces of erosion and landscape evolution in the Kruger National Park in South Africa using cosmogenic nuclide dating. 10Be‐derived catchment‐wide erosion rates (~2 and ~10 mm ka−1) are similar in magnitude to erosion and rock uplift elsewhere in South Africa, suggesting that (1) rock uplift is solely the isostatic response to erosion and (2) the first‐order topography is likely of Cretaceous age. The topographic maturity is promoted by widespread exposure of rocks resistant to erosion. Our data, however, suggest that local variations in rock resistance lead to transient landscape changes, with local increases in relief and erosion rates.

Constraining Plateau Uplift in Southern Africa by Combining Thermochronology, Sediment Flux, Topography, and Landscape Evolution Modeling

“…10.1029/2020JB021243 20 of 34 (Bierman et al, 2014;Cockburn et al, 2000;Decker et al, 2013;Dirks et al, 2016;Erlanger et al, 2012;Glotzbach et al, 2016;Keen-Zebert et al, 2016;Kounov et al, 2007Kounov et al, , 2015Scharf et al, 2013).…”

“…Figure 10.Predicted erosion rates for last 1 Myr timestep from the Cretaceous Low and Hybrid Late best fit models (a, b) compared with recent erosion rates (over the last 0.1-2 Myr) derived from cosmogenic radionuclide studies (c). Data in (c) are published data from bedrock samples or river incision rates at particular locations(Bierman et al, 2014;Cockburn et al, 2000;Decker et al, 2013;Dirks et al, 2016;Erlanger et al, 2012;Glotzbach et al, 2016;Keen-Zebert et al, 2016;Kounov et al, 2007Kounov et al, , 2015Scharf et al, 2013).…”

Quantifying erosional equilibrium across a slowly eroding, soil mantled landscape

“…Previous studies, such as the ones referenced above, quantifying soil production rates focused on landscapes eroding rapidly whereby chemical differentiation is low and physical erosion dominates the relatively high relief hillslopes. Conversely, slowly eroding, low relief landscapes are widespread on Earth and are critical to understand from a soil sustainability perspective, but there are few measurements of soil production rates for these settings (Decker et al, 2011;Portenga and Bierman, 2011;Bierman et al, 2014;Willenbring et al, 2014;Glotzbach et al, 2016;Struck et al, 2018). Their slow erosion rates tend to favor chemical weathering processes, as soil residence times are longer and the partitioning of physical and chemical fluxes tends to favor a dominant role for chemical export (Anderson et al, 2007;Larsen et al, 2014;Schoonejans et al, 2016).…”

Estimating the sediment trap efficiency of intermittently dry reservoirs: lessons from the Kruger National Park, South Africa

“…Within the framework of an ongoing study on contemporary and millennial scale erosion rates in the KNP Schmullius, 2015, 2016;Glotzbach et al, 2016;Reinwarth et al, 2017), we surveyed intermittently dry reservoirs in order to quantify reservoir siltation and average sediment yield throughout the past 30 to 80 years. The aim of this study is to establish a methodological approach for the estimation of the long-term mean TE of small reservoirs with ephemeral spillage.…”

“…The aim of this study is to establish a methodological approach for the estimation of the long-term mean TE of small reservoirs with ephemeral spillage. Within the framework of an ongoing study on contemporary and millennial scale erosion rates in the KNP Schmullius, 2015, 2016;Glotzbach et al, 2016;Reinwarth et al, 2017), we surveyed intermittently dry reservoirs in order to quantify reservoir siltation and average sediment yield throughout the past 30 to 80 years. For selected reservoirs (N = 10), the frequency and magnitude of spillage events, associated sediment discharge and the long-term mean TE of the investigated reservoirs are assessed for various scenarios based on results from fieldwork and hydrological modelling.…”