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This paper describes the methodology used for the data collection and calculation of erosion rates and presents the recent results for the period 2001-2019 for all the beaches of the Andalusian shoreline. This period is divided into two subperiods (2001-2011 and 2001-2019) to detect possible trend changes during the study years. The proxy corresponding to the internal limit of the backshore has been used, which is very useful for medium to long-term coastal erosion rates. The results show the rates calculated for this proxy, which reveal a high presence of artificially stabilised sectors where the inward migration of the shoreline associated with it is hindered, together with an intensification of the retreat rates in natural sections. Similarly, there is a clear differentiation between a relatively dynamic Atlantic façade with a higher percentage of erosive sectors and a Mediterranean façade highly conditioned by anthropic presence, with a lower percentage but a higher intensity in their values. [ABSTRACT FROM AUTHOR]

This paper describes the methodology used for the data collection and calculation of erosion rates and presents the recent results for the period 2001-2019 for all the beaches of the Andalusian shoreline. This period is divided into two subperiods (2001-2011 and 2001-2019) to detect possible trend changes during the study years. The proxy corresponding to the internal limit of the backshore has been used, which is very useful for medium to long-term coastal erosion rates. The results show the rates calculated for this proxy, which reveal a high presence of artificially stabilised sectors where the inward migration of the shoreline associated with it is hindered, together with an intensification of the retreat rates in natural sections. Similarly, there is a clear differentiation between a relatively dynamic Atlantic façade with a higher percentage of erosive sectors and a Mediterranean façade highly conditioned by anthropic presence, with a lower percentage but a higher intensity in their values.

The Zhurong rover of the Tianwen-1 mission successfully landed in the southern part of the Utopian Planitia and the northern region of the dichotomy boundary. Craters within a ~ 134 km2 region surrounding the Zhurong rover were identified and divided into seven degradation classes based on their preservation states and morphological details. Assessing how craters have degraded over time provides insight into local surface processes and then speculates on the climate evolution of the study area. The small depth/diameter (d/D) of craters in the study area may be caused by the rapid filling of sediments or by impact processes occurring in poorly cohesive weathering layers, and may also be associated with the volatile material alteration. As time went by, the process of crater degradation is nonlinear, and the degradation rate of the fresh crater in the study area at the initial stage of degradation may be as high as 0.2 m/Myr. The calculated surface erosion rate for the study area is ~ 10–2–10–3 m/Myr, indicating that the erosion of the Martian surface since the Middle Amazonian occurred in the dry environment dominated by wind-sand erosion. [ABSTRACT FROM AUTHOR]

Soil water erosion on cultivated lands represents a severe threat to soil resources in the world, and especially in Mediterranean areas, due to their topographic, edaphic and climatic conditions. Among the cultivated lands, vineyards deserve a particular attention because, aside representing one of the most important crops in terms of income and employment, they also have proven to be the form of agricultural use that causes one of the highest soil losses. Although the topic of soil water erosion on vineyards has been studied, it still raises uncertainties, due to the high variability of procedures for data acquisition, which consists into different scales of analysis and measurement methods. There is still a great gap in knowledge about the effect of triggering factors on soil water erosion and, so far, an effort to quantify this effect on the Mediterranean viticulture has not been made yet. Therefore, this paper review aims to (i) develop a documented database on splash, sheet and rill erosion rates in Mediterranean vineyards, (ii) identify and, if possible, quantify the effect of triggering factors such as topography, soil properties, rainfall characteristics and soil conservation techniques on soil water erosion, and (iii) provide suggestions for a more sustainable viticulture. Although the large variability of data, some general trends between erosion rates and triggering factors could be found, as long as data were categorized according to the same measurement method. However, no general rule upon which to consider one triggering factor always predominant over the others came out. This paper review supports the importance of monitoring soil water erosion by field measurements to better understand the relationship between the factors. However, protocols should be established for standardizing the procedure of collecting data and reporting results to enable data comparison among different study areas. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper focuses on the analysis of the slope and catchment erosion dynamics in a typical Mediterranean context and its sensitivity to recent climatic and socio-economic changes. The main objective of the present study is to test the reliability of digital photogrammetric analysis to evaluate the time and space evolution of erosion processes mainly triggered by surface running waters and landslides for about the last 60 years. The selected test area is the Landola catchment, a minor tributary of the Upper Orcia River Valley (Southern Tuscany). The Upper Orcia valley is a key site for the comprehension of denudation processes typically acting in Mediterranean badland areas thanks to the following: (i) the availability of long-lasting erosion monitoring datasets (20 years' long direct measurements at erosion 'hot spots'); (ii) its representativeness as a sub-humid Mediterranean badland area; and (iii) the rapidity of development of erosion processes, which makes it suitable as an open-air laboratory for the study of badland dynamics. The outputs of this work highlight that the application of high-resolution digital photogrammetric methodologies can represent a powerful and low-cost tool to evaluate rates and spatial-temporal distribution of denudation processes, as confirmed by the validation through field point monitoring in areas close to the study area. The results obtained for the study area confirm that high erosion rates are a persistent environmental problem for the Upper Orcia Valley, which is not solved up to now, despite various land conservation interventions. The performed multi-temporal analysis shows a slight decrease in the average water erosion rate during the last 60 years and a parallel increase in the frequency of mass wasting events. These variations are most likely related to a complex interplay between land use changes that have affected the study area during the studied period, revealing a very delicate equilibrium between farming activities and erosion processes. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The cultural value of geomorphological heritage (i.e., geomorphosites) is universally recognised and at the same time the interest on its mutability, as a consequence of both natural-climate and human pressure, is growing. In some cases a sudden increase in the velocity of processes can cause irreversible modifications threatening the survival of sites as well as their scientific value in terms of integrity. The focus of this paper is put on two types of geomorphosites (active geomorphosites and evolving passive geomorphosites), in which it is possible to observe and quantify the geomorphological processes varying mainly as a response to climate change. The study cases are runoff-derived landforms on unconsolidated deposits in two morphoclimatic contexts: 'calanchi' on marine originated clays in the Italian Apennines in Mediterranean climatic context (Crete d'Arbia and Radicofani, Tuscany) and earth pyramids formed in glacial deposits in continental Alpine environment (Pyramides d'Euseigne, Canton Valais, Switzerland). In both sites, human activities have strongly contributed to landscape evolution. To investigate erosion rates, dendrogeomorphological analysis (i.e. stress indicators and root exposure analysis) were combined with traditional quantitative geomorphological techniques. Analysis of the roots exposure, well correlated with the climatic data (denudation rates are higher during wet period), show that denudation rates are lower at Pyramides d'Euseigne due to the different texture of the deposits. Unfortunately, at the moment, a comparison between the two sites based on geomorphological monitoring data is not possible due to the different time interval of analysis, and only conclusions on denudation rates coming from roots exposure are allowed. Both geomorphosites have a high scientific value (representativeness and educational exemplarity) and are characterised by dynamicity. Providing data for modelling the sites evolution and possible decrease of their scientific value, caused by proceeding of the process itself, may be particularly significant. [ABSTRACT FROM AUTHOR]

Tillage erosion is one of the major contributors to landscape evolution in hummocky agricultural landscapes. This paper summarizes the available data describing tillage erosion caused by hand-held or other simple tillage implements as well as tools used in typical conventional agriculture in Europe and North America. Variations in equip-ment, tillage speed, depth and direction result in a wide range of soil translocation rates observed all over the world. The variety of tracers both physical and chemical gives a challenge to introduce the reliable model predicting tillage erosion, consider-ing the number and type of tillage operation in the whole tillage sequence. [ABSTRACT FROM AUTHOR]

Álvarez-Francoso, J.I.; Ojeda-Zújar, J; Díaz-Cuevas, P; Guisado-Pintado, E; Camarillo-Naranjo, J.M.; Prieto-Campos, A., and Fraile-Jurado, P., 2020. A specialized geoviewer and dashboard for coastal data visualization and exploration. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No.95, pp. 1006–1010. Coconut Creek (Florida), ISSN 0749-0208. Coastal management planning and decision making processes require geospatial data at high level of detail, which generates huge volumes of data. Besides, stakeholders need tools to integrate this information coming from a variety of sources (erosion, climate or ocean data, among others). These tools should help them to access and visualize information dynamically and interactively so they can understand, interpret and respond to multiple risks that would threaten coastal regions in order to prevent or mitigate the eventual environmental, social and economic loss. This paper presents the results of the development of a geoviewer designed to facilitate the access, visualization, exploration and dissemination of the results produced in the project entitled "Spatialisation and Web Dissemination of Erosion Vulnerability Indicators of Andalusian Beaches as a Touristic Resource", supported by the Ministry of Economy and Competitiveness of Spain. The geoviewer has been entirely built using open source software and interoperable standard web services. It allows a multi-scale visualization and is a tool of great importance for the analysis and interpretation of coastal erosion rates for the entire Andalusian coast. It will be valuable to support decision making related to this key issue in the region. [ABSTRACT FROM AUTHOR]

Investigations comparing surface downwearing rates derived from photogrammetry data and the micro-erosion meters (MEM) are limited due to the former's coarse spatial resolution and the temporal scale of data collection. These space and time limitations were revisited with the possibility of simultaneously using the Structure-from-Motion (SfM) photogrammetric workflow and the MEM. Using a cross-scale nested survey approach over one year to cover micro (10−2 m2) and meso (100 m2)-spatial scales, this paper presents erosion rates on uplifted intertidal shore platforms and marine terraces at Kaikōura Peninsula, New Zealand. The survey represents one of the first investigations combining the MEM and the SfM technique to estimate erosion rates on horizontal coastal bedrock. In a unique way, we applied established methods which allowed comparative accuracy between models via similar point matching to provide a detailed representation and visualisation of the changing rock surfaces at similar spatial and temporal scales. Over one year, across a microscale area (~0.01 m2) of rock, the MEM and SfM point clouds (SfM PCs) measured the lowest and highest erosion rates on a similar rock type and erosion site. The mean annual erosion rate of 2.244 mm/yr from the MEM was lower than the rates of 2.608 mm/yr and 10.299 mm/yr estimated using the SfM micro- and mesoscale PCs, respectively. A lower range of erosion rates (0.131 to 4.750 mm/yr) was measured using the MEM compared to erosion rates estimated from the SfM microscale PCs (0.194 to 10.106 mm/yr). Across the mesoscale (1 m2) areas, higher erosion rates were recorded using the SfM mesoscale PCs on all but one erosion site showing that a significant amount of erosion was undetected by the MEM. Using the SfM-orthomosaics, we link the erosion rates measured across the micro and mesoscale areas to intense granular disintegration, flaking, micro- and polygonal cracking and biological activities. These results provide statistical evidence to argue against extrapolating MEM erosion data obtained over small areas to larger areas on shore platforms affected by recent tectonic uplift. The implications of these findings are considered within the context of techniques for measuring shore platform erosion across spatial and temporal scales. • Erosion rates were acquired at similar spatial and temporal scales using MEM and SfM • A significant amount of shore platform erosion was undetected by the MEM • SfM PC models provided higher mean erosion rates for the micro (~0.01 m2) and mesoscale areas (1 m2) • Statistically similar mean erosion rates across microscale areas support substituting techniques. • MEM efficacy at capturing maximum erosion across microscale areas on the Kaikōura shore platforms has diminished [ABSTRACT FROM AUTHOR]

Rupture associated with the 25 April 2015 M w 7.8 Gorkha (Nepal) earthquake highlighted our incomplete understanding of the structural architecture and seismic cycle processes that lead to Himalayan mountain building in Central Nepal. In this paper we investigate the style and kinematics of active mountain building in the Himalayan hinterland of Northwest India, approximately 400 km to the west of the hypocenter of the Nepal earthquake, via a combination of landscape metrics and long- (Ma) and short-term (ka) erosion rate estimates (from low temperature thermochronometry and basin-wide denudation rate estimates from 10 Be concentrations). We focus our analysis on the area straddling the PT 2 , the physiographic transition between the Lesser and High Himalaya that has yielded important insights into the nature of hinterland deformation across much of the Himalaya. Our results from Northwest India reveal a distinctive PT 2 that separates a Lesser Himalaya region with moderate relief (∼1000 m) and relatively slow erosion ( <1 mm/yr) from a High Himalaya with extreme relief (∼2500 m), steep channels, and erosion rates that approach or exceed 1 mm/yr. The close spatial similarity in relative rates of long- and short-term erosion suggests that the gradient in rock uplift rates inferred from the landscape metrics across the PT 2 has persisted in the same relative position since at least the past 1.5 Ma. We interpret these observations to suggest that strain accumulation in this hinterland region throughout at least the past 1.5 Ma has been accomplished both by crustal thickening via duplexing and overthrusting along transient emergent faults. Despite the >400 km distance between them, similar spatiotemporal patterns of erosion and deformation observed in Northwest India and Central Nepal suggest both regions experience similar styles of active strain accumulation and both are susceptible to large seismic events. [ABSTRACT FROM AUTHOR]

In the last few decades, seafloor imagery systems have drastically changed our vision of a mostly regular and depositional marine landscape, evidencing how erosive and mass-wasting processes are widespread in the marine environments, with particular reference to geologically-active areas. Most of the previous studies have focused on the characterization of these features, whereas a very few ones have tried to estimate what is the extent and order of magnitude of erosion rates in these areas. In this paper, we show several examples from some of the most geologically-active margins off Southern Italy aimed to a) quantify the spatial extent of such processes, b) better understand the role of submarine erosion in the morphogenesis of the coastal sector, and c) try to roughly estimate the order of magnitude of erosion rates in these areas. The results are impressive, with mass-wasting features widespread from coast down to −2600, affecting from the 52% up to 97% of the whole continental slope. Because of the narrow or totally lacking shelves in these areas, mass-wasting processes often occur close to the coast and match embayment of the coast, so indicating a key role in the morphogenesis of coastal sector, with significant implication on the related geohazard. Finally, based on a morphological approach integrated by available stratigraphic constraints we have roughly estimated average erosion rates in these areas, ranging from (at least) some mm/year to a few cm/year, i.e., some hundreds of meters up to kilometers eroded in each eustatic cycle. Despite the large uncertainties of these estimates as well as their spatial and temporal variability in response to regional and local factors, the obtained values are very high and they should be considered for future model of margin evolution, source-to-sink computation and marine/coastal geohazard assessment. [ABSTRACT FROM AUTHOR]

In the last few decades, seafloor imagery systems have drastically changed our vision of a mostly regular and depositional marine landscape, evidencing how erosive and mass-wasting processes are widespread in the marine environments, with particular reference to geologically-active areas. Most of the previous studies have focused on the characterization of these features, whereas a very few ones have tried to estimate what is the extent and order of magnitude of erosion rates in these areas. In this paper, we show several examples from some of the most geologically-active margins off Southern Italy aimed to a) quantify the spatial extent of such processes, b) better understand the role of submarine erosion in the morphogenesis of the coastal sector, and c) try to roughly estimate the order of magnitude of erosion rates in these areas. The results are impressive, with mass-wasting features widespread from coast down to −2600, affecting from the 52% up to 97% of the whole continental slope. Because of the narrow or totally lacking shelves in these areas, mass-wasting processes often occur close to the coast and match embayment of the coast, so indicating a key role in the morphogenesis of coastal sector, with significant implication on the related geohazard. Finally, based on a morphological approach integrated by available stratigraphic constraints we have roughly estimated average erosion rates in these areas, ranging from (at least) some mm/year to a few cm/year, i.e., some hundreds of meters up to kilometers eroded in each eustatic cycle. Despite the large uncertainties of these estimates as well as their spatial and temporal variability in response to regional and local factors, the obtained values are very high and they should be considered for future model of margin evolution, source-to-sink computation and marine/coastal geohazard assessment. [ABSTRACT FROM AUTHOR]

The Atacama Desert is one of the driest and oldest deserts on Earth, with extremely low precipitation rates (<2 mm/yr). Mostly abiotic hyperarid environmental conditions prevail, and surface processes act at extremely low rates over the long‐term. To gain knowledge about the rate of surface processes and age of landscapes in desert environments, terrestrial cosmogenic nuclide derived erosion rate estimates can be used. Within the Huara Intrusive Complex, situated in the hyperarid core of the Atacama Desert, basin‐averaged bedrock erosion rates from channel sediments are extremely low, that is, less than 1 m/Myr. Such low rates indicate that fluvial processes operate very slowly or are almost absent. Bedrock erosion rates of channel knickpoints, however, reveal one to two orders of magnitude higher erosion rates (2–12 m/Myr). Erosion rates are remarkably low when compared to the steep surrounding topography. Tectonic uplift creates higher gravitational potentials for surface processes, controlling the overall erosion rate capacity. However, erosion itself is taking place by local precipitation capable of exceeding thresholds for surface activity. In the Atacama Desert, this happens only due to rare severe precipitation events, explaining the extremely low erosion rates. The efficiency of these events is modulated by local intrinsic processes and conditions, such as high infiltration capacities of Atacama soils and/or large channel boulder accumulations. Due to the virtual absence of these precipitation events capable of erosion, the landscape appears to be in hibernation. Plain Language Summary: The Atacama Desert is one of the driest and oldest deserts on Earth, with extremely low precipitation rates (<2 mm/yr). Surface processes operate at very low rates and on small spatial scales. To understand the rates of surface activity, cosmogenic nuclides are a widely used tool to constrain the exposure duration of sediments on the Earth's surface. Within the Huara Intrusive Complex, situated in the hyperarid core of the Atacama, basin‐averaged erosion rates from channel sediments are extremely low. Such low rates indicate that the transport of sediment is very slow or almost absent, revealing a landscape in hibernation. Bedrock erosion rates in channels, however, are one to two orders higher. The studied catchments have been subject to Quaternary tectonic activity, which can explain higher bedrock erosion rates. Rare precipitation events, typical for desert environments, have to be strong enough to provoke erosion. Processes associated with extreme long‐term aridity modulate the erosive impact of precipitation events; for example, CaSO4‐rich soils soak up water preventing surface runoff or channel boulder accumulations buffer surface flow reducing the capacity to erode. Key Points: Extremely low basin erosion rates (<1 m/Myr) in the hyperarid Atacama prevailed since the Pliocene, contrasting high relief topographyHigher bedrock erosion rates indicate that the tectonic activity is the active landscape forming mechanismThe capacity to erode is reduced by the effects of atmospheric deposition, soil inflation, and channel boulder accumulations [ABSTRACT FROM AUTHOR]

Díaz-Cuevas, P.; Prieto-Campos, A.; Fraile-Jurado, P.; Ojeda-Zújar, J., and Álvarez-Francoso, J.I., 2020. Shoreline "proxies" evaluation for mid-term erosion rates calculation in mesotidal and microtidal beaches (Andalusia, Spain). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1062–1066. Coconut Creek (Florida), ISSN 0749-0208. Coastal erosion is closely linked with the concept of sedimentary balance and traditionally is considered a relevant variable for the assessment of changes related to loss of sediments (usually computed as shoreline retreat). Nevertheless, coastal erosion can be examined through a wide variety of methodologies, each of which has its own characteristics and aims. The 3D (volumetric) method is currently the most accurate, but the lack of historical data series makes difficult a mid/long-term analysis of the phenomenon, so most studies rely on one-dimensional or bi-dimensional analysis based on aerial photographs and the use of indirect indicators (proxies), such as shoreline oscillation, using generally, the mark left by the high water line and, less frequently the backshore/foredune contact. This paper examines different proxies for the analysis of erosion rates in the mid-term in the Andalusian coast, which are exposed to different morphodynamics processes (one is in the Atlantic coast and the other one in the Mediterranean coast). In order to do this, different proxies have been digitized at a 1:2500 scale, and the erosion rates have been calculated for the period 1977-2013. The results suggest that, in general, the use of the backshore/foredune proxy is consistent, especially in Atlantic beaches (mesotidal), while the high water line proxy is used in Mediterranean beaches (microtidal), as long as the morhodynamics conditions remain homogeneous (summer season) for the dates of ortophotographies. However, the erosion rates calculated with proxies in this way should be taken with caution and supported by additional evidence for adequate interpretation. [ABSTRACT FROM AUTHOR]

Purpose: Volcanic, humid tropical landscapes are characterized by short-term geomorphic transformations due to volcanism and seismic activity, landslides, and other frequent mass movements. These landscape-forming processes are amplified by high temperatures, high annual precipitation rates, and intense rainstorms. The latter can result in significant surface runoff and sediment mobilization, even under pristine rainforest cover. However, knowledge about sediment sources and the magnitude of the associated erosion and accumulation rates remains limited in these systems. Methods: This study explores the use of radioisotopes (U-235, Bi-214, Pb-214, total Pb-210, and K-40) and of the fallout radionuclide (FRN) Cs-137 to address that knowledge gap in a pristine, tropical rainforest catchment in northern Costa Rica. We analyzed FRN and radioisotope activities from two reference soil profiles and compared them with those of 17 superficial soil samples collected on two hillslopes and of three streambed sediment samples. Results: Modeled hillslope erosion and accumulation rates ranged from 6 t ha−1 year−1 erosion to 6.7 t ha−1 year−1 deposition with up to ± 60% uncertainty reflecting spatially variable interception of rainfall inputs. Preliminary sediment fingerprinting results suggested that deeper soil material, likely originating from in-stream bank erosion and channel incision, was the dominant source of stream sediment (79 ± 19%), whereas superficial soil present on the hillslopes only contributed 22 ± 18% to the stream mixture. Conclusion: Our exploratory work highlights the potential importance of channel erosion processes in the sediment yield of steep rainforest catchments, even when hillslopes and streams have a strong hydrological connection. [ABSTRACT FROM AUTHOR]

Overtopping flows in landslide dams erode and entrain materials on the dam surface resulting in erosional features that undermine the dam stability and facilitate the subsequent outburst flooding. A comprehensive understanding of dam surface evolution is therefore crucial for flood risk assessment and hazard mitigation. In this research, we study the mechanisms that influence the non‐uniform morphology evolution of landslide dam breaches (i.e., non‐linear variation of the dam surface gradient) through experiments and numerical modeling. Analog landslide dam models, constructed using unconsolidated poorly sorted soils, are exposed to different inflow discharges. We find that although the breach discharge evolves more consistently with the erosion along the sidewalls than with bed erosion, it is the erosion along the bed that controls the change in dam surface profiles. Erosion rates, expressed as a function of the difference between the flow shear stress and the apparent erosion resistance, vary at different points along the dam surface due to localized erosional features induced by scouring. The apparent erosion resistance is found to increase linearly along the dam surface. Dam failure is numerically modeled using depth‐averaged equations which assume that the complex evolution of the dam profiles is due to the coupled effects of erosion, entrainment, and channel bed collapse. Good agreement between the observed and modeled dam profiles further demonstrates that the gradual saturation of the breach flow with entrained sediment is responsible for the linear variation of the apparent erosion resistance, which in turn contributes to the formation of the surface scouring. Plain Language Summary: Landslides that occur near rivers may block the incoming water flow forming natural dams. Landslide dams fail when the impounded water breaches the top of the dam. As the breaching flow travels along the downstream surface of the dam, it erodes surface sediment. Experiments have shown that this erosion is not uniform and that it results in non‐linear changes in the dam surface steepness. Accurate modeling of both the erosion and the evolution of the dam surface profile is important for the prediction and mitigation of outburst floods that threaten downstream establishments. In this work, we investigate the factors that shape landslide dam surfaces during dam breaches through experiments and numerical modeling. We used landslide dam models composed of unconsolidated sediments to better understand their failure process under different inflow conditions. A numerical dam failure model captures the observed complex erosion behaviors and replicates measured dam surface profiles. We then find that non‐uniform erosion is related to the saturation of the outburst floods with sediment as it travels downstream. The saturation diminishes the flood's ability to erode and entrain more surface material. This numerical model may help enhance early warning strategies for landslide dam outburst flooding. Key Points: Erosion along dam surfaces varies non‐uniformly in both vertical and lateral directionsThe non‐uniform breach morphology evolution promotes a positive feedback between the breach flow velocity and dam surface gradientsThe gradual saturation of the breach flow with sediment influences the non‐uniform breach morphology evolution of breaching landslide dams [ABSTRACT FROM AUTHOR]

Considering the pivotal role played by erosive organisms in the marine habitat and the scanty knowledge of this phenomenon in the Mediterranean Sea, the present study aimed to identify the pioneer excavating organisms occurring in the first stages of bioerosion, providing the first estimation of their rate of erosion along the North Adriatic Sea. Bioerosion activity was investigated by deploying sets of limestone panels for a period of 2 years. Moreover, micro-computed tomography was used for the first time to study polychaete erosion, confirming it is a very useful tool for the description of erosion processes. Blocks were placed in the touristic harbor Marina Dorica (Ancona) in July 2017 and periodically collected, the first time after a 6-month period, then bimonthly. Two species of the polychaete genus Polydora were the only boring organisms that settled on the experimental substrates. Erosion rate was estimated by measuring the holes produced by both worm species, and the eroded volumes obtained by resin casts of the holes. Polydora appeared after 6 months of exposure significantly changing its density rates (holes·100 cm−2·month−1) during the exposure, being comparable with densities reported from tropical areas. The erosion rate on the contrary is lower, reaching values of 0.053 g·cm−2·year−1. [ABSTRACT FROM AUTHOR]

Mountain landscapes have dynamic climates that, together with tectonic processes, influence their topographic evolution. Spatial and temporal variations in rainfall are ubiquitous in these settings as orographic precipitation patterns evolve with climate change and topography. Despite important implications such changes have for river incision, their influence is understudied. Here, we investigate how changes in rainfall pattern should affect both the steady state form and transient evolution of river profiles at the catchment scale using the stream power model. We find that spatially varied rainfall patterns can complicate steady state relationships between mean rainfall, channel steepness and fluvial relief, depending on where rainfall is concentrated in catchments, and lead to unexpected transient behavior if they are neglected. Specifically, changes in rainfall pattern cause multi‐stage transient responses that differ from responses to uniform changes in rainfall. Disparate responses by rivers that experience different rainfall conditions, particularly trunk and tributary rivers, are also an important factor in understanding catchment‐wide responses to climate change. Accounting for such disparities in sampling strategies and topographic analyses may, therefore, be vital for detecting and quantifying climate's role in landscape evolution. Lastly, we show how explicitly accounting for rainfall patterns in channel steepness indices, and thus spatial variations in erosional efficiency, may advance understanding of landscape sensitivity to climate. These results have important implications for detecting transient responses to changes in rainfall pattern (and more broadly climate), interpretation of morphometrics in steady state and transient landscapes, and quantifying the sensitivity of landscapes and erosion rates to climate. Plain Language Summary: Orographic rainfall patterns are produced when air is forced to rise over mountains, resulting in variations in rainfall with elevation. Rivers that sculpt these landscapes rely on rainfall to erode through rock. Intuitively, more rainfall means more water and typically greater erosive power. The amount of rainfall also affects how steep these rivers are, which in turn affects the steepness of the topography around them. Despite how common orographic rainfall patterns are in mountain landscapes, their effect on rivers is understudied. Here, we present a study describing how concentrating rainfall at higher and lower elevations—representing two common orographic rainfall patterns that may be enhanced or relaxed by climate change—influences the steepness mountain rivers, erosion patterns, and thus the evolution of mountain topography. We show that these orographic rainfall patterns complicate expected relationships among metrics commonly used to quantify the role of rainfall (and more broadly climate) on the topography of mountain landscapes. Further, we show that rivers respond in unexpected ways to changes in orographic rainfall patterns, as would occur following a change in climate, suggesting that common wisdom about how rivers and mountain landscapes respond to changing climates is incomplete. Key Points: Spatially variable rainfall complicates steady state relationships between mean rainfall and conventional topographic and erosion metricsTransient responses to changes in rainfall pattern differ from uniform changes in rainfall, which affects how they may be detectedRainfall gradients can obscure the sensitivity of fluvial erosion to rainfall variations and impede quantification of climate sensitivity [ABSTRACT FROM AUTHOR]

The eastern margin of Madagascar has a prominent relief change from the flat coastal plain to the low‐relief high plateau, characterizing a typical great escarpment topography at a passive margin. A quantification of the spatial distribution of erosion rates is necessary to understand the rate of landscape evolution. We present catchment‐averaged erosion rates from detrital cosmogenic 10Be concentrations, systematically covering distinct morphological zones of the escarpment. Erosion rates are differentiated across the escarpment, where the high plateau and the coastal plain are slowly eroding with an average rate of 9.7 m/Ma, and the escarpment basins are eroding faster with an average rate of 16.6 m/Ma. The Alaotra‐Ankay Graben related basins have the highest erosion rate with an average rate of 27 m/Ma. The spatial pattern of erosion rates indicates a retreating escarpment landscape. Retreat rates calculated from the 10Be concentrations are from 182 to 1,886 m/Ma. The rates of escarpment retreat on Madagascar are consistent with a model of a steady retreat from the coastline since the time of rifting, similar to the Western Ghats escarpment on its conjugate margin of the India Peninsula. Plain Language Summary: Eastern Madagascar is characterized by a distinct escarpment with high relief, normally indicative of high erosion rates. We investigate this by measuring erosion rates using cosmogenic isotope concentrations in sediment derived from throughout Madagascar. We calculated erosion rates and related these to distinct geomorphic zones. The pattern of erosion rates is consistent with inland retreat of the escarpment at about 1 km/Ma. This rate is consistent with geomorphic evidence and is comparable to the conjugate margin of western India. Key Points: Presentation of new detrital cosmogenic 10Be data that systematically covers the great escarpment of eastern MadagascarErosion rates inferred from 10Be concentrations are 9.7 to 27 m/Ma, systematically vary among distinct morphological zonesEscarpment retreat rates from 10Be concentrations are 182 to 1,886 m/Ma, consistent with evidences for captures and divide migration [ABSTRACT FROM AUTHOR]

Mollisols are of major importance for food security worldwide but are increasingly degraded by soil erosion. Mollisols in Northeast China have been converted into agricultural use only since the 19th century, but gullies are widely distributed. Gully erosion history, rates, and causes in this region remained unclear. We chose a study area with landforms and land‐use history typical for the central Mollisol region of Northeast China to estimate the initiation years and rates of gully erosion from 1968 to 2018 using aerial and satellite imageries. The outlet fan deposits of a large gully system were dated by Cesium‐137 (137Cs) and artifacts. Local farmers were interviewed to verify the results. Gully volumes were measured by a structure‐from‐motion technique using photos taken from an unmanned aerial vehicle. Our results showed that gully systems had already appeared on the steep slopes and along unpaved roads in 1968. They had become larger and more complex in 2018 by the upslope retreat of the main gullies and side gully formation. Gully incision started in the 1950s and 1960s when the original grassland and forest were completely converted into arable land. From 1968 to 2018, the gully density increased from 1.2 to 2.3 km km−2 and the gully heads retreated at speeds from 1.5 to 2.5 m yr−1. The soil loss from gully erosion ranged from 25.7 to 44.7 Mg yr−1 ha−1. These data demonstrate the severity of gully erosion in the Mollisol region of Northeast China and underline the importance of appropriate countermeasures. [ABSTRACT FROM AUTHOR]

• An analytical solution is given for suspended sediment concentration profiles in vertically unsteady scenario • Field concentration profiles in vertically unsteady scenario are recorded in the subaqueous Yellow River Delta • Key sediment parameters are optimized from best fits between modelled and measured concentration profiles • Optimized parameters are verified both in magnitude and time varying trends Accurate determinations of sediment settling velocity (w s), eddy diffusivity (D s), and pick-up rate p (t) from available field data are vital for engineering calculations or numerical simulations of coastal processes. Existing methods to determine these parameters are normally based on the assumption of a steady equilibrium that ignores the "phase lag" and "amplitude damping" effects of a diffusing concentration in unsteady scenarios that are typical of many field settings. The present paper gives an analytical solution for a time-varying suspended sediment concentration profile C (z,t) in the horizontally uniform but one-dimensional vertical (1DV) unsteady scenario with a vertically constant D s distribution. The model is used to estimate w s , D s , and p (t) by determining best fits between the modelled and C (z,t) profiles measured with an instrumented quadripod in the subaqueous Yellow River Delta (YRD) during a local sediment resuspension event. Values of field-derived w s range from 0.01 to 0.073 mm/s, while D s range from 2 × 10−5 to 1.46 × 10−4 m2/s, and p (t) range from 8.3 × 10−5 to 3.14 × 10−4 kg m−2 s−1 under mild and energetic wave conditions, respectively, which are consistent with our laboratory measurements and with the results reported in the literature; time variations of the derived parameters are also reasonable in response to the synchronous hydrodynamics, both confirm that the parameter optimizations are successful. The proposed analytical model is shown to be a practical tool for inferring w s , D s , and p (t) from available measured C (z,t) profiles free of secondary prediction equations or unknown empirical parameters. [ABSTRACT FROM AUTHOR]

A secondary objective for the Perseverance rover mission to Jezero crater, Mars, is to collect igneous rocks for analysis on Earth. The mafic crater floor unit (MFU) represents the best candidate. Ten‐meter‐scale craters on the MFU exhibit rocky ejecta, rims, and slopes that indicate resistant rock. The frequency distribution of these craters is, however, low. Comparisons of MFU craters to craters on a lava plain at the Interior Exploration using Seismic Investigation, Geodesy and Heat Transport mission (InSight) landing site reveal that the MFU lacks a granular regolith. Removal of regolith or exhumation of the MFU explains the rocky crater morphology and low density. Erosion rates, calculated using crater retention timescales of ~2.0 Ga for both locations, are 10−3 to 10−4 m/Myr. The rates derive from craters impacted into rocky materials on the MFU versus regolith at InSight. The difference in material strength, yet comparable erosion rates, requires more vigorous surface processes at Jezero relative to global averages on Mars. Plain Language Summary: Jezero crater is a 45‐km diameter impact crater on Mars. It contains a river delta and deposits that suggest that it was once filled by a lake. Jezero is the landing site for NASA's Mars Perseverance rover, scheduled to land in February 2021. A primary objective of the rover is to sample rocks to determine if Mars was once habitable for life. A secondary objective is to obtain igneous rocks, or rocks that crystallize from magma or lava. Igneous rocks can be used to provide absolute age constraints on the rocks that they surround or are contained within. The purpose of this study is to evaluate a geologic unit called the mafic floor unit that is the best candidate for sampling igneous material. Small craters that formed from meteor impacts in the floor unit are surrounded by large rocks that suggest that the material is resistant to weathering and erosion, consistent with craters impacted into hard igneous rocks or other competent material. However, the unit lacks a sand‐sized surface soil that is typical of most lava plains on Mars. Comparisons to the InSight landing site indicate that wind may be responsible for removing sandy material and exposing rock. Key Points: The mafic floor unit at Jezero crater is a morphologically resistant unitThe mafic floor unit at Jezero crater lacks a granular surface regolith like other lava plains on MarsSurface processes operate at relatively higher rates within Jezero crater compared to global averages on Mars [ABSTRACT FROM AUTHOR]

Where tectonics is not a factor, the landscapes of granite batholiths show variations in average pluton elevation that follow each pluton's composition very closely. The granitoids of the Kosciusko and Maragle batholiths in the Highlands of southeastern New South Wales have clearly been influenced by tectonics. Examination of the relation between composition and mean pluton elevation reveals that the plutons of these batholiths lie in two groups, a Highlands group between the Jindabyne-Barney's Range Thrusts and the Tumut Ponds Fault Zone and a Western group west of the Tumut Ponds Fault Zone. Composition and mean pluton elevation are strongly correlated within each group, indicating they have been uplifted as two coherent blocks along those two fault systems. The plutons of the Berridale Batholith east of the Highlands form a contrasting low-relief group. Pluton mineralogy determines elevation across a granite batholith. Kosciusko Highlands were uplifted as one block along the Jindabyne Thrust and Tumut Pond Fault Zone. [ABSTRACT FROM AUTHOR]

The InSight mission to Mars landed within Homestead hollow on an Early Amazonian lava plain. The hollow is a 27‐m‐diameter, 0.3‐m‐deep quasi‐circular depression that shares morphologic and sedimentologic characteristics to degraded impact craters. Unlike the intercrater plains outside of the hollow, the interior lacks cobbles and is dominated by loose sand, granules, and pebbles. Fresher craters near the landing site exhibit meter‐scale bedforms in their ejecta and on their floors due to sediment trapping. The sedimentology of the interior fill of Homestead hollow suggests similar trapping. The hollow falls along a morphologic continuum that requires low rates of rim degradation and fill. Crater degradation rates (rim erosion plus filling) in the landing site decline nonlinearly through time from 10−2 to 10−4 m/Myr as craters evolve to a hollow‐like form. Rim erosion rates are lower initially, at 10−3 m/Myr, but converge with degradation rates to 10−4 m/Myr. This implies that while filling plays an important role soon after crater formation, it is limited in later stages. Crater statistics indicate that the bulk of the fill occurred in the first ~50 Myr for Homestead hollow. The estimated maximum age of the hollow is ~400 to 700 Myr. This requires near‐zero fill aggradation and long‐term soil stability for the bulk of the crater's history. Fill stability manifests in Homestead hollow as a ~5‐ to 10‐cm‐thick duricrust, formed by exchanges of atmospheric water vapor with soil. The estimated degradation in the hollow requires ~2 to 3 m of sedimentary fill beneath the lander. Plain Language Summary: The Interior Exploration using Seismic Investigation, Geodesy and Heat Transport (InSight) mission to Mars landed in western Elysium Planitia. The landing site consists of a smooth, flat surface that is unique relative to the surrounding rockier plains. Observations from orbital satellite imagery indicate that InSight landed inside of an almost circular depression in the landscape. Here we evaluate the shape and form of this small circular depression and compare it against nearby degraded impact craters. We conclude that InSight landed inside a very old crater that has filled in with windblown sediment and slope debris from the crater wall. We also estimate that the crater has been sitting on the landscape, experiencing extremely slow degradation, for approximately 400 to 700 Myr. The crater origin for the depression has implications for our understanding of the materials that exist immediately beneath the lander and the results from the two geophysical instruments onboard InSight, the Seismic Experiment for Interior Structure (SEIS) and Heat Flow and Physical Properties Package (HP3). Key Points: InSight landed within a 27‐m‐diameter, 0.3‐m‐deep, degraded impact crater called Homestead hollowHomestead hollow has a maximum age of 400 to 700 Myr. Degradation rates were two orders of magnitude higher in first 50 Myr after impactHomestead hollow is filled with up to 3 m of loose infill that is composed of sand and pebbles. The hollow fill is capped by a duricrust [ABSTRACT FROM AUTHOR]

An alpine permafrost talus slope at Flüelapass (Eastern Swiss Alps) was observed using annual terrestrial laser scanning measurements between 2009 and 2018. The high‐resolution digital elevation models derived from these measurements enabled the detection and quantification of mass wasting processes with an accuracy of a few centimeters. Rock fall, snow avalanche erosion, and debris flow tracks could be distinguished and their quantitative and qualitative contribution to talus slope growth and shaping was examined. Erosion rates were calculated for each of the investigated processes and an estimate for the recession rate of the talus slope head wall is reported. Currently, debris flows supply most of the debris inputs to the talus slope, while snow avalanches were found to play an important role in reshaping its surface morphology. Rock fall causes distinct grain size sorting down the slope, as the travel distance of rocks increase with their size. The presented data and results illustrate the current processes occurring at the talus slope surface, which appear to differ in quantity and quality from those during the onset of the talus slope formation. [ABSTRACT FROM AUTHOR]

Sidewall erosion because of rockfalls is one of the most efficient erosional processes in the highest parts of mountain ranges; it is therefore important to quantify sidewall erosion to understand the long‐term evolution of mountainous topography. In this study, we analyse how the 10Be concentration of supraglacial debris can be used to quantify sidewall erosion in a glaciated catchment. We first analyse, in a glaciated catchment, the cascade of processes that move a rock from a rockwall to a supraglacial location and propose a quantitative estimate of the number of rockfalls statistically mixed in a supraglacial sand sample. This model incorporates the size of the rockwall, a power law distribution of the size of the rockfalls and the mean glacial transport velocity. In the case of the Bossons glacier catchment (Mont Blanc massif), the 10Be concentrations obtained for supraglacial samples vary from 1.97 ± 0.24 to 23.82 ± 1.68 × 104 atoms g−1. Our analysis suggests that part of the 10Be concentration dispersion is related to an insufficient number of amalgamated rockfalls that does not erase the stochastic nature of the sidewall erosion. In the latter case, the concentration of several collected samples is averaged to increase the number of statistically amalgamated rockfalls. Variable and robust 10Be‐derived rockwall retreat rates are obtained for three distinct rockfall zones in the Bossons catchment and are 0.19 ± 0.08 mm year−1, 0.54 ± 0.1 mm year−1 and 1.08 ± 0.17 mm year−1. The mean 10Be retreat rate for the whole catchment (ca. 0.65 mm year−1) is close to the present‐day erosion rate derived from other methods. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Cattle stock ponds on the fringe of metropolitan Phoenix, USA, experienced a wide range of land‐use changes over the period from 1989 to 2009. This research measures soil erosion from watersheds of different rock types, variable relief, and land uses. Monitoring sediment accumulation behind 18 earthen berms at each major land‐use transition enabled calculations of soil erosion rates. Compared with the first decade of study with more precipitation and cattle grazing, accelerated urbanization in the drier second decade increased soil erosion from wildfires by up to 4.2×, from exposure of bare ground due to building construction by up to 3.4×, and from bare ground exposure due to road and pipeline construction by up to 3.1× overgrazing alone. Stock pond watersheds underlain by granite experienced statistically significant higher erosion rates compared with watersheds underlain by metamorphic, basalt, and other rock types. Global sediment yield data for warm desert (BWh Köppen‐Geiger) sites reveal that our data plot consistently with other grazed study areas with a tendency for higher area‐specific sediment yields in smaller drainage areas. These sediment yield data, however, do not support previously published generalizations of anomalously high or low sediment yields from warm desert settings. Desert urbanization processes accelerate soil erosion, resulting in the need for regulatory agencies to impose new erosion mitigation strategies. [ABSTRACT FROM AUTHOR]

Sea cliffs represent 80% of the world's coasts and can be found virtually in all types of morphogenetic environments. Most studies on rocky environments focused on the impacts of modern sea level rise on cliff stability derived from sequential surveys, direct measurements or erosional features in anthropogenic structures. In this study, we explore the potential of dendrogeomorphic techniques to quantify multidecadal changes in coastal environments on Porquerolles Island (France). We sampled a total of 56 cross‐sections from 16 Pinus halepensis Mill. roots growing on former alluvial deposits and on sandy‐gravelly cliffs to quantify mean annual cliff retreat rates as well as changes in cliff geometry. Anatomical changes in roots have been used successfully in the past to quantify continuous denudation rates on slopes, channel incision and gullying processes but the approach has not been used so far in a coastal cliff context. At Porquerolles Island, reconstructed rates of cliff retreat cover 30–40 years and show average erosion rates between 0.6 and 3.9 cm yr−1 (average: 2.1 cm yr−1). Highest rates are observed at Pointe de la Tufière (2.6–3.9 cm yr−1), a small rock promontory that is more exposed to wave and storm surges than the remainder of the study area. By contrast, lower erosion rates are recorded at cliffs protected by the La Courtade pocket beach (0.6–1.9 cm yr−1). This contribution demonstrates that dendrogeomorphic analyses of roots clearly have a significant potential and that they are a powerful tool for the quantification of multidecadal rates of cliff retreat in areas where measurements of past erosion are lacking. More specifically, the approach also has clear advantages over the shorter time series obtained with repeat monitoring (e.g. terrestrial laser scanning, sensors, erosion pins) or over longer, but more coarsely resolved records obtained from aerial photographs or radio‐nuclides. © 2018 John Wiley & Sons, Ltd. Determination of exposure years was based on the sharp decrease of cell lumen area of earlywood tracheids. This contribution demonstrates that dendrogeomorphic analyses of roots clearly have a significant potential and that they are a powerful tool for the quantification of multidecadal rates of cliff retreat in areas where measurements of past erosion are lacking. [ABSTRACT FROM AUTHOR]

A compilation of seismic data has been used to characterize the Neogene‐Quaternary sedimentary succession of the northwestern Barents Sea continental margin to better understand the paleoenvironmental evolution and the sedimentary processes involved. The Neogene strata are dominated by contourites related to the ocean circulation established from the opening of the Fram Strait connecting the Atlantic and the Arctic Oceans (< ~17.5 Ma). The upper Plio‐Pleistocene strata (< ~2.7 Ma) are dominated by stacked gravity‐driven deposits forming trough‐mouth fans that were sourced from paleo‐ice streams. Within the interfan areas, contouritic sedimentation prevailed. Thus, this margin provides an example of interaction of glacigenic debris flows, contour currents, and hemipelagic/glacimarine sedimentary processes. A total of ~29,000 km3 of sediments with an average sedimentation rate of about 0.24 m/Kyr were estimated. These numbers reflect the sediment input to this part of the Arctic Ocean from the northwestern Barents Sea shelf and adjacent land areas. For the first time, the average erosion and erosion rates for this source area are estimated using a mass balance approach. Approximately 410–650 m of erosion has on average occurred, corresponding to an average erosion rate of ~0.15–0.24 m/Kyr. These rates are comparable to those reported from other glaciated margins, including the western Svalbard and mid‐Norway margin, but up to only half the rates reported from the western Barents Sea margin. This variation is interpreted due to the size and bedrock types of the drainage area, ice dynamics, and the continental slope gradient. Plain Language Summary: This study is about mapping the offshore glacial sediment by using seismic data in the northeastern Svalbard‐northern Barents Sea continental margin. The studied margin provides a unique opportunity to examine an interaction between downslope and along‐slope sediment processes. Development of Kvitøya glacial fan is highlighted and shows a major sediment delivery under ice streams that reached the shelf break. Prior to or at the onset of glaciation, a major slope failure likely occurred generating a large submarine slide, named Body A. For the first time, the average erosion and erosion rates during the last ~2.7 million years are estimated from this margin. We found out that 410–650 m of sediments were removed from the source area. The erosion rates are estimated (0.15–0.24 m/Kyr) and are comparable with other formerly glaciated margins. This study is an important scientific input for a better understanding of uplift and erosion in the Barents Sea shelf. The present contribution is highly relevant for future hydrocarbon exploration in the Barents Sea area and Arctic region. Finally, investigating such subsurface sediments is crucial for paleoenvironmental reconstruction in order to understand the climate dynamics in the past. Key Points: Quantification of the glacial sediment input to the Arctic Ocean from the northwestern Barents Sea is presentedFor the first time, average erosion and erosion rates are estimated from the source area of this margin using a mass balance approachThese rates are comparable to those reported from other glaciated margin, but only about half compared to the western Barents Sea margin [ABSTRACT FROM AUTHOR]

Rocky ejecta craters (RECs) at the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) landing site on Elysium Planitia, Mars, provide constraints on crater modification and rates for the Hesperian and Amazonian. The RECs are between 10 m and 1.2 km in diameter and exhibit five classes of preservation. Class 1 represents pristine craters with sharp rims and abundant ejected rocks. From Classes 2 to 5, rims become more subdued, craters are infilled, and the ejecta become discontinuously distributed. High‐Resolution Imaging Science Experiment digital elevation models indicate a maximum depth to diameter ratio of ~0.15, which is lower than pristine models for craters of similar size. The low ratio is related to the presence of a loosely consolidated regolith and early‐stage eolian infill. Rim heights have an average height to diameter ratio of ~0.03 for the most pristine class. The size‐frequency distribution of RECs, plotted using cumulative and differential methods, indicates that crater classes within the diameter range of 200 m to 1.2 km are separated by ~100 to 200 Myr. Smaller craters degrade faster, with classes separated by <100 Myr. Rim erosion can be entirely modeled by nonlinear diffusional processes using the calculated timescales and a constant diffusivity of 8 × 10−7 m2/year for craters 200 to 500 m in diameter. Diffusion models only partly capture depth‐related degradation, which requires eolian infill. Depth degradation and rim erosion rates are 10−2 to 10−3 m/Myr, respectively. The rates are consistent with relatively slow modification that is typical of the last two epochs of Martian history. Plain Language Summary: The shape and form of impact craters on Mars can tell us something about processes that operate on the surface and therefore inform our understanding of the planet's climate. Small, 100‐m‐scale craters have a known bowl‐shaped form in their pristine state. Over time, wind, gravity, and, in some cases, ice and water, degrade them to nearly flat landforms. This study analyzes the degradational sequence of craters at the InSight landing site to infer something about surface processes and climate history at this location. InSight is a geophysical mission that is set to land on Elysium Planitia in November 2018. The craters show a broad range of morphologies that suggest slow, long‐term degradation. The data indicate that over time, ejected rocks and crater rims disappear at rates that suggest degradation by dry processes like gravity failure and wind erosion. Furthermore, the craters also show evidence of being filled, likely by wind‐driven sand. The calculated rim erosion rates and infill rates are similar to other landing sites on Mars and suggest a cold, hyperarid climate. This is consistent with the age and equatorial location of the terrain, which formed well after the warmer and wetter period of Mars history. Key Points: Presence of a meter‐thick regolith and eolian infill results in relatively shallow, fresh craters at the InSight landing siteRim erosion can be modeled by diffusional processes, but diffusion only partly captures depth changes, which requires eolian infillSurface process rates at the InSight landing site are consistent with slow modification that is typical of last two epochs of Mars history [ABSTRACT FROM AUTHOR]

Tillage erosion is one of the major contributors to landscape evolution in hummocky agricultural landscapes. This paper summarizes the available data describing tillage erosion caused by hand-held or other simple tillage implements as well as tools used in typical conventional agriculture in Europe and North America. Variations in equipment, tillage speed, depth and direction result in a wide range of soil translocation rates observed all over the world. The variety of tracers both physical and chemical gives a challenge to introduce the reliable model predicting tillage erosion, considering the number and type of tillage operation in the whole tillage sequence.

Erosion is one of the major issues currently facing coastal areas. Some consequences of this process are beach loss and higher flood risk, which will likely be exacerbated given ongoing sea-level rise. With this in mind, those responsible for conservation and management decisions need appropriate tools with which to identify critical coastal areas, as well as to analyse, interpret, and visualise them with the appropriate geomorphological and environmental background. The aim of this work was to present a methodology for improving the analysis and interpretation of coastal erosion rates, as well as to guarantee wide access and dissemination of erosion data. To that end, an approach for the production, management, and dissemination of shoreline erosion data for the Andalusian coast in Southern Spain was developed. This approach enables the analysis and interpretation of the erosion rates in coasts by linking erosion rates with geomorphological and thematic information using a data model. Additionally, this methodology was proven to be a valid and appropriate tool for the design of a web-based viewer, being the best way to represent the erosion rates obtained every 50 m of shore for the entire Andalusian coast, being an exposed coastal front 917 km long. This is particularly useful for integrated coastal zone management schemes, enabling quick and easy access to valuable information. [ABSTRACT FROM AUTHOR]

An advanced method to study geomorphology of the well-known inselberg landscape in Finnish Lapland is introduced. Conventionally topographical maps and altitude reference produced from stereographic aerial photographs has been used. Now the LiDAR data has opened a new way to study geomorphology and terrain in detail. We applied the new methods in eastern Finnish Lapland from where seven inselbergs have been identified and analysed. With an accurate elevation data and images we could identify the detailed morphology in the inselbergs and examine the processes that actively alter the terrain. LiDAR data opened a view to the preglacial history and processes. Some preliminary estimations of the rate and amount of preglacial erosion could be made. It seems that erosion rate may have been in order of 2-10 m/Myr in Lapland based on existing datings and stratigraphic observations. Weathering and erosion history in Lapland is long as the kaolinite clays of Late Cenozoic, Mesozoic or even Mesoproterozoic in age are found in the weathered bedrock. Although all disconformities older than the Mesozoic era have probably been eroded to an unidentifiable extent, there is good reason to suppose that the main characteristics of the relief, including inselbergs, originated as early as the Late Cretaceous or at least in the Palaeocene. [ABSTRACT FROM AUTHOR]

Knowing how much sediment check dams have trapped during their lifespan is essential to estimate their effectiveness or the sediment yields of their basins. Methods to calculate the volume of sediment trapped by check dams play an important role in the understanding of these issues. Several authors have proposed different methods to measure the volume of retained sediment, but their accuracy has, as yet, not been precisely determined and is currently a subject of debate. We compare the most frequently used methods (geometric: prism, pyramid and geometric; topographic: Digital Terrain Models (DTMs), trapezoids and sections methods) to evaluate their accuracy and precision in determining the volume of sediment retained by check dams. Our calculations are based on ten virtual check dams simulated in several gullies of Saldaña (Spain), where we determine their volumetric capacity for trapping sediment (real volume). This was made by means of an intensive topographic survey of these gullies, employing a terrestrial laser scanning system to obtain a high-resolution digital elevation model (5 × 5 cm, ±2 mm). The results showed that topographic methods provided a very good fit to real volume with a difference of around 8%, being the sections method the most accurate. Geometric methods were less accurate, showing differences of up to 28%. Thus, the results obtained until now by geometric methods should be considered with caution. Although topographic methods were more accurate, they require many field data and much time than the others. So geometric methods can still be useful by correcting their results using our obtained percentage of variation. Knowing the accuracy of the methods before measuring is essential to obtain the most reliable results to analyse the role of check dams in controlling sediment, erosion processes and land degradation. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Erosion rates in residual limestone soils in a humid climate were measured for 10 years at one site, and for 4 years at another site, using erosion pins. Erosion pins were placed in gully floors and on convex divides between adjacent gullies, on abandoned land where vegetation had been removed. We measured an average erosion rate of 20 mm yr−1over 10 years at one site and only 5 mm yr−1over 4 years at another site where chert gravel was common on the surface. The 10-year average erosion rate of divides (26 mm yr−1) was significantly greater than the average erosion rate of gullies (14 mm yr−1), suggesting control by different processes, some of which may be seasonal. In winter, it was observed that frost action produced a thin layer of loose soil on the surface of divides. In summer, a hardpan developed on divides, as the soil loosened by winter frosts was transported to gullies, likely by rainsplash or dry ravel. The diffusive processes of frost action, rainsplash, and dry ravel appear to shape the convex divides in this study. Down-cutting of gullies requires channelized flow produced by intense rainfall, which is more common in summer for this location. [ABSTRACT FROM AUTHOR]

The presence of rocks in the ejecta of craters at the InSight landing site in southwestern Elysium Planitia indicates a strong, rock-producing unit at depth. A finer regolith above is inferred by the lack of rocks in the ejecta of 10-m-scale craters. This regolith should be penetrable by the mole of the Heat Flow and Physical Properties Package (HP). An analysis of the size-frequency distribution (SFD) of 7988 rocky ejecta craters (RECs) across four candidate landing ellipses reveals that all craters >200 m in diameter and ${<}750 \pm 30\ \mbox{Ma}$ in age have boulder-sized rocks in their ejecta. The frequency of RECs however decreases significantly below this diameter ( $D$ ), represented by a roll-off in the SFD slope. At $30\ \text{m} < D < 200\ \text{m}$ , the slope of the cumulative SFD declines to near zero at $D < 30\ \text{m}$ . Surface modification, resolution limits, or human counting error cannot account for the magnitude of this roll-off. Rather, a significant population of <200 m diameter fresh non-rocky ejecta craters (NRECs) here indicates the presence of a relatively fine-grained regolith that prevents smaller craters from excavating the strong rock-producing unit. Depth to excavation relationships and the REC size thresholds indicate the region is capped by a regolith that is almost everywhere 3 m thick but may be as thick as 12 to 18 m. The lower bound of the thickness range is independently confirmed by the depth to the inner crater in concentric or nested craters. The data indicate that 85% of the InSight landing region is covered by a regolith that is at least 3 m thick. The probability of encountering rockier material at depths >3 m by the HP however increases significantly due to the increase in boulder-size rocks in the lower regolith column, near the interface of the bedrock. [ABSTRACT FROM AUTHOR]

Sediments from the small lake Ilsø situated in the Illerup/Alken Enge Valley were studied in order to investigate past landscape development at the time of a probably ritual human mass burial following battle during the Roman Iron Age ( ad 1-400). A pollen record from Ilsø and a number of other records from Jutland were combined using the Landscape Reconstruction Algorithm to reconstruct local vegetation changes through the last 2,800 years. These methods were supplemented by studies of catchment-related geochemistry of the Ilsø lake sediments. The results show a marked reforestation event associated with a strong decrease in erosion levels at the very beginning of the first century ad, contemporaneous with the finds of human remains at Alken Enge. Comparison with a pollen record 10 km away and with those from other sites, reveals that this reforestation occurs unusually early and rapidly, and is an unparalleled development in a Danish context. We suggest that the major landscape changes at the beginning of the Roman Iron Age and forest cover for the next few centuries comprise a possible example of ritual control of local land-use. [ABSTRACT FROM AUTHOR]

The spatial distribution of land management practices (LMPs), such as the use of vegetated filters, may have a strong impact on their efficiency in trapping sediments and pollutants. Distributed water erosion models help managers, planners, and policymakers optimize the efficiency of these LMPs regarding their location relative to water and sediment pathways. In this work, the authors analyzed the impact of the spatial distribution of LMPs using an existing distributed model and sensitivity analysis procedures. The distributed model that was used is a distributed single-event physically based water erosion model developed to calculate erosion rates and sediment flow for small (less than 10 km²) agricultural catchments. To measure the impact of the spatial distribution of LMPs, the authors developed a stochastic model that generates LMP locations over the entire catchment. The stochastic model has three input parameters: the density of LMPs, their downslope/ upslope location probability, and the probability density function shape controller. Because of its ability to account for the cross effects between parameters, the variance-based Sobol method was used to calculate the sensitivity of the soil loss ratio of a typical Mediterranean agricultural catchment (Roujan, southern France) to the LMP locationmodel parameters. Threemeasurement points (two subcatchment outlets and themain outlet) were used to examine the spatially distributed effects of the LMP locations. The simulation results indicated that 70% of the variation of the net erosion is explained by variations in LMP density for the main outlet catchment, making LMP density the most sensitive parameter. However, the total Sobol sensitivity indices indicate a strong interaction among the three parameters when the density values are low (few LMPs are applied). Thus, although the density of the LMPs is themost sensitive parameter, their locationmay influence their global trapping efficiency in (real) cases where few LMPs are applied. [ABSTRACT FROM AUTHOR]

Erosion rates are key to quantifying the timescales over which different topographic and geomorphic domains develop in mountain landscapes. Geomorphic and terrestrial cosmogenic nuclide (TCN) methods were used to determine erosion rates of the arid, tectonically quiescent Ladakh Range, northern India. Five different geomorphic domains are identified and erosion rates are determined for three of the domains using TCN 10Be concentrations. Along the range divide between 5600 and 5700 m above sea level (asl), bedrock tors in the periglacial domain are eroding at 5.0 ± 0.5 to 13.1 ± 1.2 meters per million years (m/m.y.)., principally by frost shattering. At lower elevation in the unglaciated domain, erosion rates for tributary catchments vary between 0.8 ± 0.1 and 2.0 ± 0.3 m/m.y. Bedrock along interfluvial ridge crests between 3900 and 5100 m asl that separate these tributary catchments yield erosion rates <0.7 ± 0.1 m/m.y. and the dominant form of bedrock erosion is chemical weathering and grusification. Erosion rates are fastest where glaciers conditioned hillslopes above 5100 m asl by over-steepening slopes and glacial debris is being evacuated by the fluvial network. For range divide tors, the long-term duration of the erosion rate is considered to be 40-120 ky. By evaluating measured 10Be concentrations in tors along a model 10Be production curve, an average of ~24 cm is lost instantaneously every ~40 ky. Small (<4 km2) unglaciated tributary catchments and their interfluve bedrock have received very little precipitation since ~300 ka and the long-term duration of their erosion rates is 300-750 ky and >850 ky, respectively. These results highlight the persistence of very slow erosion in different geomorphic domains across the southwestern slope of the Ladakh Range, which on the scale of the orogen records spatial changes in the locus of deformation and the development of an orogenic rain shadow north of the Greater Himalaya. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]