TY - JOUR
T1 - Aspect-dependent bedrock weathering, cliff retreat, and cliff morphology in a hyperarid environment
AU - Shmilovitz, Yuval
AU - Enzel, Yehouda
AU - Morin, Efrat
AU - Armon, Moshe
AU - Matmon, Ari
AU - Mushkin, Amit
AU - Pederson, Joel
AU - Haviv, Itai
N1 - Publisher Copyright: © 2022 Geological Society of America
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Deciphering aspect-related hillslope asymmetry can enhance our understanding of the influence of climate on Earth’s surface morphology and the linkage between topographic morphology and erosion processes. Although hillslope asymmetry is documented worldwide, the role of microclimatic factors in the evolution of dryland cliffs has received little attention. Here, we address this gap by quantifying aspect-dependent bedrock weathering, slope-rill morphology, and subcliff clast transport rates in the hyperarid Negev desert, Israel, based on light detection and ranging (LiDAR)-derived topography, clast-size measurements, and cosmogenic 10Be concentrations. Cliff retreat rates were evaluated using extrapolated profiles from dated talus flatirons and 10Be measurements from the cliff face and sub-cliff sediments. We document systematic, aspect-dependent patterns of south-facing slopes being less steep and finer-grained relative to east and north-facing aspects. In addition, cliff retreat and clast transport rates on slopes of the south-facing aspect are faster compared to the other aspects. Our data demonstrate that bedrock weathering of the cliff face and the corresponding grain size of cliff-derived clasts delivered to the slopes constitute a first-order control on cliff retreat and sediment transport rates. We demonstrate that the morphology of the cliff and the pattern of bedrock weathering co-vary with the solar radiation flux and hence that cliff evolution in hyperarid regions is modulated by aspectdependent solar radiation. These results help to better understand interactions between climate and dryland surface processes.
AB - Deciphering aspect-related hillslope asymmetry can enhance our understanding of the influence of climate on Earth’s surface morphology and the linkage between topographic morphology and erosion processes. Although hillslope asymmetry is documented worldwide, the role of microclimatic factors in the evolution of dryland cliffs has received little attention. Here, we address this gap by quantifying aspect-dependent bedrock weathering, slope-rill morphology, and subcliff clast transport rates in the hyperarid Negev desert, Israel, based on light detection and ranging (LiDAR)-derived topography, clast-size measurements, and cosmogenic 10Be concentrations. Cliff retreat rates were evaluated using extrapolated profiles from dated talus flatirons and 10Be measurements from the cliff face and sub-cliff sediments. We document systematic, aspect-dependent patterns of south-facing slopes being less steep and finer-grained relative to east and north-facing aspects. In addition, cliff retreat and clast transport rates on slopes of the south-facing aspect are faster compared to the other aspects. Our data demonstrate that bedrock weathering of the cliff face and the corresponding grain size of cliff-derived clasts delivered to the slopes constitute a first-order control on cliff retreat and sediment transport rates. We demonstrate that the morphology of the cliff and the pattern of bedrock weathering co-vary with the solar radiation flux and hence that cliff evolution in hyperarid regions is modulated by aspectdependent solar radiation. These results help to better understand interactions between climate and dryland surface processes.
UR - http://www.scopus.com/inward/record.url?scp=85165088861&partnerID=8YFLogxK
U2 - https://doi.org/10.1130/B36442.1
DO - https://doi.org/10.1130/B36442.1
M3 - Article
SN - 0016-7606
VL - 135
SP - 1955
EP - 1966
JO - Bulletin of the Geological Society of America
JF - Bulletin of the Geological Society of America
IS - 7-8
ER -