Where shallow landslides can be ruled out as the cause of channel initiation, the area-threshold concept is commonly invoked to explain the occurrence of channel heads. This concept implies that a certain depth of overland flow must be reached before incision can occur, and that this depth depends on the contributing area upslope of a point of interest.
We investigate the applicability of this concept to Barro Colorado Island (BCI), a tropical rainforest landscape known for a low soil permeability by forest standards and a pronounced wet season with high-intensity rainfall events. We define “low permeability” by the frequency with which selected rainfall intensities exceed soil permeability, expressed as saturated hydraulic conductivity (Ksat), at shallow depths. Thus, while the median of maximum 30-min rainfall intensities of 5 mm/h exceeds on (spatial) average Ksat at a depth of 0.15 m, in some places the same metric does not exceed Ksat until a depth of 0.5 m. BCI is also know for the frequent occurrence of overland flow of the “wide-spread” type, a vague concept occasionally invoked but hitherto undefined. Hence, the area-threshold approach appears applicable.
We conceptualize channel heads as point processes on flow networks. The covariates slope, curvature, flow accumulation and flow convergence were chosen as candidate explanatory variables that control the occurrence of these points. Using stepwise regression as a model-selection technique, we derived a log-linear model involving the covariates flow accumulation and flow convergence and their interaction term. These results suggest that the accumulation of discharge in the direct vicinity of the channel head and on the upslope contributing area dominate channel formation in this environment and that the probability of a pixel being a channel head decreases with increasing flow accumulation or flow convergence. Thus, the discharge amount was a main driver of channel head formation. While this seems to vindicate the area-threshold concept, the difficulty of predicting channel head locations warrant a look at the subsurface, besides considering technical issues such as DEM resolution or the precision of GPS readings under a thick forest canopy. The coincidence of some channel heads with return flow suggests that surface-based metrics alone do not explain their spatial distribution.

How to cite: Lenz, K. T., Schwanghart, W., and Elsenbeer, H.: Channel initiation in a low-permeability landscape, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21646, https://doi.org/10.5194/egusphere-egu24-21646, 2024.

Scarplands worldwide, underlain by tilted or undeformed sedimentary successions, display a distinct morphology with relief asymmetry between steep escarpments and gentle plateaus. This asymmetry drives escarpment retreat towards the plateau, gradually eroding the old plateau. Residual flat-topping landforms, commonly known as 'residual hills', 'mesas', 'buttes', or 'witness mountains,' prominently rise above the surrounding areas. Traditionally seen as remnants of an ancient plateau, these landforms are believed to endure escarpment retreat due to their capping by resistant rocks (e.g., sandstones, basalts, or duricrusts). This widely accepted conceptual explanation has yet to undergo testing through numerical modelling.

Here, we propose a distinct mechanism for the rapid formation of 'witness mountains' — drainage capture dynamics during escarpment retreat. Using a 2-D numerical landscape evolution model incorporating stream-power-driven river incision and linear hillslope diffusion (representing mass wasting processes), we simulate escarpment evolution in tilted and undeformed multi-layered stratigraphy. As rivers draining down the escarpment capture low-sloping plateau rivers, a knickzone rapidly propagates upstream through the captured river system, followed by steepening hillslopes behind the escarpment front. This process results in flat-topped drainage divides bounded by marginal escarpments in both the front and back of the initial escarpment, forming 'witness mountains'. With equally steep slopes on both sides, these 'witness mountains' do not retreat towards the plateau. Instead, they gradually decay in elevation in situ until their distinctive morphology is no longer discernible. Similar results emerge in simulations assuming uniform lithology, suggesting drainage capture can sculpt 'witness mountains' beyond differential erosion resistance.

Our simulations suggest that 'witness mountains' can be rapid outcomes of local drainage capture events affecting the scarpland foreland. This insight, supported by empirical observations in the Southwestern German Scarplands, challenges conventional interpretations of landscape evolution, offering valuable perspectives for understanding scarpland transience.

How to cite: Peifer, D., Beer, A. R., Glotzbach, C., Neely, A. B., Bernard, T., and Schaller, M.: 'Witness mountains' on scarplands are expected outcomes of drainage capture dynamics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14132, https://doi.org/10.5194/egusphere-egu24-14132, 2024.

Human influence in the form of hydraulic engineering causes disruption to unconfined channel transport in catchments. Hydrotechnical construction includes, among others: weirs, dams, retention reservoirs, river bank supports, bridges, etc. Each of these structures causes disruptions in the flow of trailed and suspended sediments originating from denudation in the river catchment. It is widely known that the dynamic balance of the river bed is disturbed by sediment accumulation upstream of the reservoir's dam, limited sediment outflow from the reservoir, and increased downcutting downstream of the dam. The aim of the study was to investigate the influence of reservoir and additional river regulation facilities on selected rivers in Poland on the structural and functional connectivity of the river channel in terms of sediment transfer from slope denudation in the catchment areas. The study examined a high-resolution digital elevation model together with survey data on sediment accumulation sites along the river. It was shown that a more detailed and realistic connectivity pattern for hillslopes and river channels can be obtained by applying several tools and parameters simultaneously (i.e. field surveys, modelling, etc.).

The study uses the concept of connectivity. A spatial examination of catchment linkages enables a determination of the degree to which a catchment participates in the transfer of sediment in suspended form and the pathways used to facilitate this. A detailed analysis of such pathways is needed to plan appropriate river engineering work and efforts designed to reduce sedimentation in reservoir and downstream erosion as well as efforts to remove dams in situations where this is deemed to be the most appropriate solution.

We observed in the study area, the highest values of the IC were noted for valleys of streams where suspended sediment transfer occurs through multiple pathways found in the vicinity of streams. Conversely, the lowest index values were noted for mouth section areas found near the studied reservoir, where sediment deposition occurs in the form of alluvial fans. In foothill areas sediment transported in stream channels usually comes from lateral bank erosion as well as stream bed erosion in the Wapienica. In foreland basins part of the catchment, the influx of sediment occurs at select sites, mostly via drainage ditches. The presence of levees along rivers and concrete lining of channels effectively prevents sediment influx from area hillslopes. On the other hand, the use of rubble in the channel bed impedes channel floor erosion and channel bank erosion. The largest number of sites where suspended material is supplied to fluvial transport pathways are found in middle mountain areas, followed by foothill areas, and finally foreland basins.

How to cite: Piasecka-Rodak, J., Święchowicz, J., Najwer, A., and Zwoliński, Z.: Impact of river engineering drivers on denudation processes in a small catchment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6763, https://doi.org/10.5194/egusphere-egu24-6763, 2024.

The negative effects of soil erosion vary widely including pollution and siltation of water bodies, reduced crop yields, organic matter loss, diminished water storage capacity. These adverse effects generate significant consequences on developing as well as modern societies, possibly leading to land abandonment and the decline of rural communities and therefore posing fundamental social challenges. While protection of the soil resources is rightfully considered an important target of environmental policy, it is crucial to accurately understand the impacts of soil erosion and allocate funds for mitigation. Achieving this requires a precise assessment of erosion rates and their geographical distribution. as well as the targeting of funds to remedy soil erosion requires a correct assessment of the amount of erosion that is occurring and of its geographical distribution. Accurate quantification of soil erosion is not only essential for environmental policy but also holds scientific significance. Recent studies stressed the importance of comprehending human-induced impacts on sediment fluxes as well as their potential effects on global biogeochemical cycles. This need is even accentuated in a context where there is a demand to assess with reasonable confidence the impact of rapid climate and land use changes on these budgets. This crucial information is often lacking.

To measure the rates and geographical extent of soil erosion, both indirect and direct methods have been used. Indirect methods generally measure soil profile truncation or sediment accumulation relative to a reference soil horizon, exposed or buried reference object (such as roots, foundations…), or to the loss or accumulation of tracers. These methods are more suitable for studying historical erosion. To assess current erosion rates, direct methods, typically plot or catchment monitoring and field-based measurements (e.g. mapping of erosion features) are preferred. Among these, field-based methods are most effective.

Based on the application of different monitoring methodologies in various social and physical environments, this study aims at bringing some insights into the causes of soil erosion rate variations across these different environments. The methodologies employed will range from long-term high-resolution monitoring at plot or catchment and river system scales to dating sediment cores in reservoirs. The relative importance of climatic against physiographic and anthropogenic factors will also be discussed.

How to cite: Cerdan, O., Bizeul, R., Evrard, O., Foucher, A., Gaillot, A., Grangeon, T., Landemaine, V., Minella, J., Pak, L. T., and Salvador-Blanes, S.: Rate of soil denudation from plot scale to river system in different social and physical environments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16804, https://doi.org/10.5194/egusphere-egu24-16804, 2024.

Denudation and the relative shares of chemical and mechanical processes and denudation are controlled by a range of environmental drivers and are in most environments and landscapes worldwide significantly affected by anthropogenic activities and disturbances. Anthropogenic pressures can significantly affect the sediment (dis)connectivity in defined drainage areas.

The Quisi, Pou Roig, and Mascarat drainage basins in eastern Spain (Calpe region) are located as neighbouring drainage-basin systems in a Mediterranean, mostly mountainous and anthropogenically modified environment. The drainage basins show significantly different characteristics. Quisi has the highest share of urbanized surface areas and has, at the same time, a comparably high availability of fine-grained sediments. Pou Roig and Mascarat have large shares of terraced surface areas, with Mascarat being the steepest of the three drainage-basin systems.

The three intermittent streams drain directly into the Mediterranean Sea. The selected study areas are characterized by a mild Mediterranean climate with a mean annual air temperature of ca. 18°C and a mean annual precipitation sum around 435 mm (measured slightly above sea level). During the coldest months (January, February) frost and snow can occur in the highest elevations although the mountain ranges are situated close to the coast. In contrast, maximum summer temperatures (July, August) can easily exceed 30°C and south-facing hillslopes and rockwalls are exposed to high solar radiation. The lithology in the area is clearly dominated by marine limestones. Elevation ranges from sea level up to 1126 m a.s.l. Relevant geomorphological processes include chemical and mechanical weathering, rockfalls, debris flows, splash and slope wash, fluvial erosion, and fluvial solute, suspended sediment and bedload transport.

This ongoing GFL-research (since 2018) is focussed on the detection of sediment sources, sediment (dis)connectivity, spatiotemporal variability and rates of contemporary denudational processes and land-to-sea solute and sedimentary fluxes. Our work includes detailed field and remotely sensed geomorphological mapping and computing of morphometric drainage basin parameters, combined with the statistical analysis of high-resolution meteorological and rock-temperature data, and the observation and monitoring of sediment-transfers, runoff and fluvial-transport events. In the field, we are using a combination of different observation, monitoring and sampling techniques, including different tracer techniques and sediment traps in stream channels, remote time-laps cameras, and event-based high-resolution field monitoring combined with frequent water and sediment samplings.

Sediment connectivity is significantly reduced by extended terraced areas within the drainage-basin systems, particularly in Pou Roig and Mascarat. Sediment transfers, the intermittent runoff, and fluvial transport and land-to-ocean fluxes are almost entirely controlled by pluvial events. High runoff during extreme rainfall events forms a relevant hazard particularly in the lower parts of the drainage-basin systems. Mechanical fluvial denudation shows a clearly higher spatiotemporal variability than chemical denudation, with the highest rates of mechanical fluvial denudation being measured in the Quisi drainage basin. Altogether, drainage-basin wide chemical denudation dominates over drainage-basin wide mechanical fluvial denudation which is explained by partly limited sediment availability, sediment deposition and short- to long-term sediment storage at numerous defined locations within the drainage-basin systems, and by the predominant marine limestones found in the drainage-basin areas.

How to cite: Beylich, A. A. and Laute, K.: Sediment (dis)connectivity and contemporary rates of chemical and mechanical denudation in selected Mediterranean drainage basin systems in eastern Spain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4064, https://doi.org/10.5194/egusphere-egu24-4064, 2024.

The young-glacial relief of the Polish Lowland, together with the retouching of Holocene morphogenesis, is one of the youngest in Poland. Three landscape features clearly distinguish the young glacial zone: significant hypsometric diversity (-1.8 m b.s.l. - 328.6 m a.s.l.), a developing and genetically complex valley/river network and the presence of a dense network of post-glacial troughs and undrained depressions, including those filled with lakes. This zone is represented by complexes of post-glacial, slope, fluvial, aeolian and denudational landforms. The most characteristic complexes of forms in the young glacial landscape are hypsometrically diversified hills and frontal moraine embankments, extensive gently undulating areas of bottom moraine plateaus, flat outwash areas, sometimes deeply incised subglacial channels, river valleys usually with a meridional course and often with a gap character, and ice-marginal valleys with a latitudinal course. Late-glacial and Holocene retouching mainly includes erosional edges remodeled by periglacial denudation basins, erosional cuts of different ages with alluvial fans at their outlets, as well as dune plain areas. The contemporary relief of the young glacial zone is shaped primarily by chemical denudation predominating over mechanical denudation, erosion and accumulation of water flowing down the plains and slopes, intense deep erosion in the upper reaches of rivers, processes of building up flood terraces and lateral erosion in the lower reaches of rivers, as well as processes degradation and aggradation, caused by human activity.

Attempts to estimate the intensity of mechanical and chemical denudation have been developed on a large scale since the 1970s. The main denudative morphogenetic processes in upland and outwash areas today include: chemical denudation, water erosion and aeolian deflation, and to a lesser extent suffusion.

Recognition of contemporary slope morphogenesis indicates that mass movements and gully erosion play a minor role in it, with soil washing predominating. The lowest wash-out values occur within turf areas (meadows, grassy fallows). Wash-out in agricultural crops has quite wide ranges of values for cereals, potatoes and black fallow, respectively. On surfaces with an inclination of 0-2º, wash-out associated with water runoff occurs extremely rarely and has little morphogenetic significance. The amount of dispersed wash-out was determined to be larger compared to forest areas. The range of variability of wash-out volumes is usually very seasonal, although the highest wash-out values are usually caused by heavy rainfall in spring and early summer. Concentrated wash-out processes, characteristic of upland edge zones, are repeated on the same fragments of slightly converging slopes and, together with plow erosion, result in the formation of wash-out basins. The analysis of these forms shows that on average there are several of them per 10 square km. The average density of road gulches is very low. There are much fewer of them than gullies, the average density of which is much higher. Intensive linear erosion, under favorable conditions, may lead to the formation of deep grooves and furrows, which are not leveled as a result of normal agrotechnical procedures and may give rise to gullies.

How to cite: Zwoliński, Z., Mazurek, M., Andrzejewski, L., Florek, W., Kostrzewski, A., Podgórski, Z., Rachlewicz, G., Smolska, E., Stach, A., Szmańda, J., Szpikowski, J., and Wysota, W.: Present-day denudation rates in postglacial landforms of the Polish Lowlands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19702, https://doi.org/10.5194/egusphere-egu24-19702, 2024.

Snow avalanches (SAs) are one of the debris transfer mechanisms that affect steep slopes of alpine and subalpine belts in the Carpathian Mountains. In remote areas of Carpathians where SA activity is poorly documented, the hazard assessment is hampered by the lack of information about past SA events. This is the case in Sureanu Mountains (Southern Carpathians, Romania), where archival records of the past SAs are missing. There is an urgent need for hazard zonation mapping, as in the last decades, recreational activities attracted an increasing number of tourists reaching the SA-prone slopes in this high mountainous area. This study aims to increase the knowledge on SA history by reconstructing SA events based on tree-ring records in five adjacent avalanche paths in Sureanu Mts. For this purpose, Norway spruce trees (Picea abies (L.) Karst.) exhibiting clear signs of mechanical disturbances caused by the past SAs were sampled. Growth anomalies (e.g., scars, tangential rows of traumatic resin ducts, compression wood and growth suppression sequences) were identified within the annual rings of disturbed trees and served to reconstruct spatial extent, frequency, and return periods of SAs within each of the investigated path. In forested areas of Sureanu Mts. without any monitoring, tree-ring methods allowed to reconstruct spatio-temporal activity of SAs with annual resolution. This information may significantly improve the knowledge of the avalanche regime and contribute to the avalanche hazard zonation in the studied area.

How to cite: Pop, O.: Timing and spatial extent of snow avalanches inferred from tree rings in Sureanu Mountains (Southern Carpathians, Romania), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11781, https://doi.org/10.5194/egusphere-egu24-11781, 2024.

Topography and relief reflect the long-term competition between tectonics and surface processes linked to climate. The integration of tectonics, climate and surface processes in numerical modelling have the potential to quantify landscape evolution over large periods of time. Analytical methods such as 1) low-temperature thermochronology sensible to long timescale (i.e. ~Myrs) and 2) cosmogenic nuclide concentrations sensible to shorter time scales (i.e., ~Kyrs) allow the calibration of such models. Analyses of a catchment’s topography combined with the previous analytical data can, therefore, be used to reconstruct the continuous uplift or erosion history of this specific landscape. However, reconstruction at larger spatial scale where numerous catchments are involved remains challenging. Difficulties arise from different base-levels, tectonics and climate settings that control the different catchments forming the vast landscape.

            In this study, we reconstruct the erosion rate of Germany. The numerical model solves river erosion, hillslope diffusion and 1D heat transfer to predict river profiles, cosmogenic nuclide concentrations and low-temperature thermochronological ages. The model algorithm utilizes the efficient inverse modelling scheme “Simulation-Based Inference”. Simulations of the inverse modelling use neural networks to learn the observed data in order to predict high-dimensional unknown parameters such as uplift and erodibility. River profiles extracted from a DEM are combined with pre-existing and new low-temperature thermochronological data as well as cosmogenic nuclide concentrations across entire Germany. We perform individual inverse modelling of the different types of datasets for the main catchments in Germany in order to estimate erosive parameters. Initial results suggest highly variable uplift and erodibility between the different catchments. Hence, further analyses have to be performed in order to combine the different results over a large-scale domain.

How to cite: Bernard, T., Glotzbach, C., Neely, A., Peifer, D., Beer, A., Schaller, M., Shi, Y., and Ehlers, T. A.: Erosion rate estimation across a large-scale domain from surface analyses, thermochronology and cosmogenic nuclide concentrations: A case study from Germany., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20146, https://doi.org/10.5194/egusphere-egu24-20146, 2024.

Denudation is the sum of chemical weathering and physical erosion. It is a key parameter controlling the evolution of the Earth’s surface, the production of soils, the stability of relief or the long-term evolution of climate through silicate alteration and sedimentary fluxes that control the burial of organic carbon. Through these controls, denudation influences large scale biogeochemical cycles. In turn, climate is supposed to have a strong control over denudation through a number of processes such as precipitation, temperature or vegetation distribution. In order to comprehend the past evolution of the Earth’s surface and to better predict future changes that will affect our habitat, it is crucial to constrain links that exist between climate and denudation, notably because the intensity of these feedback mechanisms is still debated. This requires precise quantification of past denudation rates. We propose here to pursue this goal using cosmogenic radionuclides (¹⁰Be), a method which has already proven its efficiency for this particular kind of study. We apply this method to a Quaternary sedimentary archive from the Mozambique Canal, offshore southwestern Madagascar.

The choice of the study area is motivated not only by data availability, but also by the absence of intense tectonic activity or glaciations over the Quaternary, limiting changes in denudation rates over time to climatic forcings, hence simplifying the system we wish to study. We measured in situ cosmogenic ¹⁰Be in quartz grains of turbiditic layers from a marine sedimentary core that has been dated between 50 and 900 ka, and that was drilled on a terrace of the underwater Tsiribihina valley, in the Mozambique Canal. A preliminary study demonstrated that this core covers several glacial-interglacial cycles. New ¹⁰Bedata hence allows us to document paleo-denudation rates integrated over a large drainage basin through several Quaternary glacial-interglacial cycles. In order to investigate the sources of the terrigenous sediments brought from Madagascar to the Mozambique Canal during the past 900 ka we also used εNd, which is an efficient source tracer for ancient lithologies, such as in Madagascar (Mesoarchean to Neoproterozoic), as well as heavy mineral counting. This integrated approach allows us to reconstruct paleo-denudation rates from a well delimited region during the Pleistocene.

Overall, the Mangoky river appears to be the dominant source of sediments to the Mozambique Channel. Variations in sources are limited and do not follow climate cyclicity. Our ¹⁰Be-based denudation rates range from 21 ± 7 mm/ka at 136 ka to 89 ± 36 mm/ka at 614 ka. Denudation rates appear generally higher during interglacial periods, when the monsoon periods are believed to be either longer or stronger in terms of precipitation intensity. Between 600 ka and 400 ka glacial denudation rates are modified, but not interglacial denudation rates, meaning that there must be a change in a process controlling denudation during glacial, even in a region unaffected by glaciers.

How to cite: Charreau, J., Large, E., Blard, P.-H., Bayon, G., Garzanti, E., Denielou, B., and Jouet, G.: Monsoon over Quaternary climatic cycles control on denudation rates of southwestern Madagascar over the past 900 ka, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16786, https://doi.org/10.5194/egusphere-egu24-16786, 2024.

The uplift of the Tibetan Plateau is crucial for understanding both regional and global climate dynamics. This uplift, and the interplay between climate and tectonics, profoundly influences surface exhumation. The creation of a climatic divide due to mountain uplift results in starkly different weather patterns, with the windward side receiving more precipitation and the leeward side forming drier rain shadows. These climatic differences have consequential long-term impacts on exhumation, and therefore, are key to our understanding historical mountain landscapes like the Himalayas and the Andes. This study explores these distinct exhumation as indicators of ancient mountain ranges. By integrating new and existing apatite fission track (AFT) and apatite helium (AHe) data, we reveal exhumation's spatial variability across the plateau, providing insights into its geological history. The discernible disparities suggest a high-elevation watershed divide near the current latitude of ~31°N existed before the Eocene, influencing precipitation and exhumation in the plateau’s southern regions. The northern regions, in the lee of this divide, show reduced exhumation rates, except in areas of tectonic activity. High exhumation rates at the plateau's orogenic front zones suggest these boundaries locations are key to understanding its expansion; tracking these zones gives clues about the plateau's growth. While pinpointing the onset of higher exhumation is complex due to continuous tectonic activity, focusing on the expansion of the interior—represented by a slower exhumation zone—proves more revealing. Our research indicates that the plateau expanded bilaterally from the latitude ~31°N and implicates the Tibetan Plateau's development since the Eocene as a factor in the Earth's climatic evolution, potentially influencing global cooling.

How to cite: Ge, Y., Fox, M., Zhang, H., Liu, J., Shen, X., and Wang, C.: Variations in Exhumation as Evidence of Climate Divergence and Historical Uplift of the Tibetan Plateau, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4718, https://doi.org/10.5194/egusphere-egu24-4718, 2024.

The Earth surface, where life develops and stands, is strongly affected by denudation which is the sum of physical erosion and chemical weathering. Denudation impacts soil formation and agriculture, affects the relief stability and, at the geological time scale, controls the atmospheric CO₂ via the weathering of silicates and the production of sediments that later bury organic matter in the oceans. In the context of global warming, it is particularly important to predict how denudation will change and hence impact the Earth Surface where we live. This requires to understand the links between past climate variability and denudation changes, especially during the Quaternary when Earth experienced rapid climate oscillations of amplitude similar to what is expected in the future due to anthropic impact. To reach this goal, quantitative estimate of past denudation rates during the Quaternary are needed especially in Volcanic island located in tropics because here silicate weathering and hence CO2 consumption is particularly efficient.

In this study, we reconstruct Quaternary paleo-denudation rates in Santoa Antao, one of the largest islands of the Cabo Verde archipelago that is located in the Atlantic ocean 800 km off the coast of Senegal. To reconstruct the paleo-denudation rates we measured in situ cosmogenic ³He concentrations in ancient fluvial sediments stored in deep entrenched valleys across the island. The depositional ages of sediments were determined by dating using Ar/Ar adjacent volcanic layers (pumices or basalt lavas). For comparison between all data, paleo-denudation rates are normalized to modern ³He derived denudation rates across the same drainage basin obtained from the analysis of modern river sand in a previous study. This yields to a 0-550ka record of paleo-denudation rates that is compared to climate variations to discuss the potential links between the two.

How to cite: Pik, R., Charreau, J., Blard, P.-H., Nomade, S., Scao, V., and Parmentier, A.: Quaternary denudation rates in a tropical volcanic island: example of Santo Antao in Cabo Verde, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15626, https://doi.org/10.5194/egusphere-egu24-15626, 2024.

On the eastern coast of Petunia Bay there is a complex of tundra lakes at various stages of geosuccession. A characteristic feature is the occurrence of tundra lakes on raised sea terraces. The geoecosystem of raised sea terraces with tundra lakes is clearly separated from the neighboring geoecosystems in terms of geology, lithology, morphology, hydrology and phytosociology. The lowest erosion-accumulation terraces from the middle and younger Holocene range from 5 to 16 m a.s.l. The terraces are composed of marine gravel and rock deposits with a significant content of calcium carbonate and the remains of malacofauna. The research results indicate diverse sources of origin of denudation solutes occurring in coastal lakes. The conducted research contributed to the creation of a model of the functioning of tundra lakes. Mapping and field tests of bedrock sediments were carried out in designated geoecological zones around lakes: sampling of sediments for mechanical and petrographic composition, measurement of humidity, temperature, specific conductivity EC, pH and calcium carbonate content in the soil. In addition, drilling was carried out in the lake sediments and around the lake, based on which the nature and rate of denudation processes were estimated.

How to cite: Zwoliński, Z., Mazurek, M., Paluszkiewicz, R., and Janiec, P.: Record of denudation processes in the sediments of a tundra lake (Petuniabukta, Central Spitsbergen), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19959, https://doi.org/10.5194/egusphere-egu24-19959, 2024.