Controls on denudation rates in tectonically stable Mediterranean carbonate terrain

Abstract

cited By 13International audienceno abstrac

Weathering-limited hillslope evolution in carbonate landscapes

“…Using a regolith dissolution rate of 0.01% per year produces a surface lowering of ∼30 mm/ka, close to observed values in the Luberon summit surface and elsewhere in peri-Mediterranean regions (Furlani et al, 2009;Ryb et al, 2014bRyb et al, , 2014a.…”

“…The limiting factors on carbonate dissolution have already been thoroughly investigated by Ryb et al (2014bRyb et al ( , 2014aRyb et al ( , 2015 across the Mediterranean and arid landscapes of Israel. Mean annual precipitation is 700 mm/yr over the Luberon Mountains, where water availability is likely to be limiting chemical weathering processes (Ryb et al, 2014a).…”

“…Recent advances on the calibration of 36 Cl production rate from Ca spallation have opened the way for the implementation of similar approaches in carbonate landscapes (Stone et al, 1994;Schimmelpfennig et al, 2009). For example, Ryb et al (2013Ryb et al ( , 2014bRyb et al ( , 2014a have provided important insights into the spatial distribution of denudation for carbonate dominated landscapes across a strong climatic gradient in Israel. The significant control of the precipitation gradient on the denudation pattern support the idea that dissolution is the major regulator of the evolution of such landscapes and that physical processes play only a secondary role, unless water availability becomes limiting for chemical weathering.…”

Limestone weathering rates accelerated by micron-scale grain detachment

“…It is striking that the rates calculated here for the Western Wall are remarkably similar to the value (obtained using cosmogenic isotope measurements) of 21 ± 7 mm k.y. -1 (6.7 ± 2.2 × 10 -13 m s -1 ) reported for exposed bedrock carbonate rocks in the Judean Hills surrounding Jerusalem (Ryb et al, 2014). The similarity between the rates obtained using two entirely different methods (i.e., lidar versus cosmogenic isotopes) suggests that ancient edifices can in fact serve as reliable indicators of natural long-term carbonate erosion rates.…”

“…One of the difficulties with assessing the magnitude of carbonate dissolution is the large uncertainty concerning the rates of carbonate weathering in field settings. Many field experiments last no longer than several years, and cosmogenic isotope methods that can provide estimates of longterm rates have so far been limited (e.g., Stone et al, 1994;Matsushi et al, 2010;Ryb et al, 2014). Moreover, while chemical weathering is often assumed to be the dominant erosional mechanism in carbonates (e.g., Simms, 2004;Noiriel et al, 2009), mechanical processes could also be a significant factor in removing material from eroding rock surfaces (Vleugels and Van Grieken, 1995;Goldie, 2005).…”