Sand residence times of one million years in the Namib Sand Sea from cosmogenic nuclides

Soil Erosion Rates in South Africa Compared With Cosmogenic 3he-Based Rates of Soil Production

“…However, given that the particulate load for rivers globally is estimated to be only 75 % to 90 % of the total load (Wilkinson, 2005) with the dissolved load being the remainder, an average Holocene denudation rate of 3.3 -3.7 m/Myr may be assumed for the Orange River basin. This is within error of the value determined over a longer period by Vermeesch et al (2010), although Compton et al (2010) considered Holocene denudation rates to be heterogeneous across the region. In addition, the observation that in situ-produced soils in southern Africa (fluvial and aeolian deposits excluded) are generally < 1 m thick and thinner in arid areas of Karoo sedimentary rock outcrop (Schulze, 2007) is compatible with steady state, weathering-limited soil erosion rates for the Quaternary/late Neogene.…”

“…Previous cosmogenic nuclide studies in southern Africa (Fleming et al, 1999;Cockburn et al, 1999;2000;Bierman and Caffee, 2001;Van der Wateren and Dunai, 2001;Kounov et al, 2007;Codilean et al, 2008;Dirks et al, 2010;Vermeesch et al, 2010) have been primarily concerned with testing models of long term landscape evolution, yet cosmogenic nuclide data can also provide a natural baseline against which the rates of present-day surface processes may be assessed (e.g. Hewawasam et al, 2003;Vanacker et al, 2007).…”

The beginning of the Buntsandstein cycle (Early–Middle Triassic) in the Catalan Ranges, NE Spain: Sedimentary and palaeogeographic implications

“…The uniform composition of the dune sands in the Catalan Ranges could indicate only one source area, but not a constant source of sand. Sand could have a long residence time within the same area, reaching even more than one million years, as in the present-day Namib Desert (Vermeesch et al, 2010). In the southern Iberian Ranges, the timeequivalent rocks are of fluvial origin, however, they locally show aeolian reworked grains and thin horizons constituting part of the sandy fluvial bars .…”

Influence of cell size on volume calculation using digital terrain models: A case of coastal dune fields

“…Numerical models are necessary to study the evolution of aeolian dune fields whose development occurs over a timescale of hundreds to millions of years (Livingstone et al, 2010;Vermeesch et al, 2010) because this timescale is beyond observational data. Numerical simulations address variations of the dune field properties (volume, area, etc.)…”

“…The volume of sand stored in a dune field depends on the sand flux through time, which is sensitive to climate change. Thus, the calculation of dune field volume combined with dating methods to determine ages of aeolian sand deposition, such as that based on cosmogenic nuclides (Vermeesch et al, 2010) or luminescence (Wintle, 1993;Lancaster, 2008), permit to obtain a more complete record of the climate variables affecting the evolution of dune fields and their coupled depositional systems. Numerical simulations play an important role in understanding the response of dune fields to climate change.…”