Quantifying rock uplift rates using channel steepness and cosmogenic nuclide–determined erosion rates: Examples from northern and southern Italy

Abstract

Bedrock river channel steepness index can be used to infer relative differences in rock uplift rates across a landscape, given uniform lithology and climatic forcing. River incision, E, is

Identification of tectonically active areas using DEM: a quantitative morphometric analysis of Mt. Medvednica, NW Croatia

“…In our study, k sn val ues were com puted with q ref value of 0.45, fol low ing sug ges tion of Whipple (2004), which al lowed us to com pare the com puted k sn val ues to the val ues col lected in other stud ies (Whipple, 2004;Wobus et al, 2006;Cyr et al, 2010;Ismail and Abdelsalam, 2012).…”

“…Suc cessively, k sn val ues are de ter mined for in di vid ual slope-area stream seg ments us ing q ref val ues (see Wobus et al, 2006;Cyr, 2010). Ref er ence con cav i ties, ac cord ing to Wobus et al (2006) and Ismail and Abdesalam (2012), are usu ally in the range between 0.35 and 0.65, re flect ing stream chan nels free of knickpoints, fault ac tiv ity or lithological het er o ge ne ity av er aged on a re gional scale.…”

How concave are river channels?

“…As of the writing of this manuscript, dozens of papers have used slope-area analysis to infer uplift or erosion rates (e.g., Snyder et al, 2000;Kirby and Whipple, 2001;Kobor and Roering, 2004;Wobus et al, 2006a;Harkins et al, 2007;Cyr et al, 2010;DiBiase et al, 2010;Kirby and Whipple, 2012;Vanacker et al, 2015). integral analysis we henceforth refer to reference m/n ratios rather than interchanging m/n and θ.…”

“…The channel steepness index, k s , is related to erosion rate by: Whipple and Tucker (1999) demonstrated that at steady state, defined here as where rock uplift rate, U , is equal to the erosion 15 rate, E, both alluvial channels and bedrock channels should both exhibit the power law scaling of equation (3). In addition, Whipple and Tucker (1999) suggested that m/n should fall in the range 0.35 ≤ m/n ≤ 0.6 if bedrock incision is driven by shear stress.…”

“…In the Sperchios Basin this has resulted in strong gradients in χ across topographic divides (Figure 14), particularly between the large catchments draining the landscape behind the footwall (which have likely been gaining drainage area), and the short, steep catchments draining across the footwall (which have likely been truncated). Where catchments are growing or shrinking, relationships between χ and elevation are expected to deviate systematically from a steady-state straight profile, with aggressor catchments having steeper χ profiles (resulting in 15 higher apparent m/n derived from topography) and victims having gentler χ profiles (lower m/n). This is consistent with our observations of low m/n ratios in short, steep catchments draining across the footwall that may have lost drainage area during fault growth.…”