Climate and relief‐induced controls on the temporal variability of denudation rates in a granitic upland

Abstract

How soil erosion rates evolved over the last about 100 ka and how they relate to environmental and climate variability is largely unknown. This is due to a lack of suitable archives that help to trace this evolution. We determined in situ cosmogenic beryllium‐10 (10Be) along vertical landforms (tors, boulders and scarps) on the Sila Massif to unravel their local exhumation patterns to develop a surface denudation model over millennia. Due to the physical resistance of tors, their rate of exhumation may be used to derive surface and, thus, soil denudation rates over time. We derived soil denudation rates that varied in the range 0–0.40 mm yr‐1. The investigated boulders, however, appear to have experienced repositioning processes about ~20–25 ka bp and were therefore a less reliable archive. The scarps of the Sila upland showed a rapid bedrock exposure within the last 8–15 ka. Overall, the denudation rates increased steadily after 75 ka bp but remained low until about 17 ka bp. The exhumation rates indicate a denudation pulse that occurred about 17–5 ka bp. Since then the rates have continuously decreased. We identify three key factors for these developments – climate, topography and vegetation. Between 75 and 17 ka bp, climate was colder and drier than today. The rapid changes towards warmer and humid conditions at the Pleistocene–Holocene transition apparently increased denudation rates. A denser vegetation cover with time counteracted denudation. Topography also determined the extent of denudation rates in the upland regime. On slopes, denudation rates were generally higher than on planar surfaces. By determining the exhumation rates of tors and scarps, soil erosion rates could be determined over long timescales and be related to topography and particularly to climate. This is key for understanding geomorphic dynamics under current environmental settings and future climate change. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.

A model for evaluating continental chemical weathering from riverine transports of dissolved major elements at a global scale

“…For several decades, evaluation and quantification of CW has been the focus of hydrogeochemical research (Livingstone, 1963;White and Blum, 1995;Di Figlia et al, 2007;Jansen et al, 2010;Hartmann et al, 2014a;Raab et al, 2019) and in more recent years it has also been used to quantify trends in salt increases related to human activities (Meybeck, 2003;Moosdorf et al, 2011;Guo et al, 2015;Kaushal et al, 2018). Large-scale studies have focused CW analysis on its implications for atmosphere/land/ocean fluxes and the Earth's climate, in influencing the biogeochemical cycles of elements by regulating CO 2 consumption, or nutrient release (Amiotte Suchet and Probst, 1993b; Amiotte Suchet and Probst, 1995;Dupré et al, 2003;Hartmann et al, 2014a).…”

Influence of Relief Degree of Land Surface on Street Network Complexity in China

“…RDLS is frequently used as one of the indicators of habitat suitability evaluation [15] and ecological environment evaluation [16]. It is also widely used in the fields of geological disaster evaluation [17], soil erosion sensitivity evaluation [18], and population distribution and economic development [19]. An urban street network is the basic skeleton of urban spatial form that expresses evident complexity in many aspects, including topology structure [20].…”

The story of a summit nucleus: hillslope boulders and their effect on erosional patterns and landscape morphology in the Chilean Coastal Cordillera

“…Taller boulders and boulders with longer residence times (such as those on the slope of Cerro Anay Hill in NA and the slope of Santa Gracia Hill in SG; Table 2) were exhumed during one or more glacial-interglacial cycles; during such climatic transitions, soil denudation rates could have changed. Similarly, Raab et al (2019) suggested that soil denudation rates surrounding tors in southern Italy shifted in conjunction with climate changes over the course of their exhumation (around 100 ka). However, our approach yields an average soil denudation rate over the time of boulder exhumation; therefore, we can only speculate regarding whether soil denudation rates were variable.…”