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The Himalaya, a leading example of active mountains, is jointly shaped by intense tectonics, extreme climate and surface denudation. However, the causal relationship among these agents remains controversial. In this work, by an integrated analysis of bedrock channels and valley hillslopes using process-based models, we discover 3D-linear correlations in logarithmic space among precipitation-estimated stream discharge, channel gradients and valley hillslope gradients. This finding indicates that channel incision and hillslope denudation are dynamically coupled in sculpting the erosional topography in tectonically active domains of the Himalaya. The channel-hillslope coupling provides an independent approach to quantify key parameters of erosional models. Surface denudation indices simulated along streams and in drainage basins present a regular arrangement of high- and low-denudation zones across the Himalaya, which coincides well with available thermochronological and structural data and thereby supports a tectonic dominance on surface denudation rates and topography over medium-long timescale.

The increase of geomorphological research during the last decades in the Gorce Mts. caused the need for state-of-art review papers. The Gorce Mountains were formed as an isolated massif with Mt Turbacz (1310 m a.s.l.) as the highest summit. River channels are remodeled by sudden and high-level floods with the critical impact of log jams. The main processes influencing hillslope relief were landsliding, run-off, and tree uprooting. The review suggests the following issues await for studies: a long-term landscape evolution, monitoring of morphogenetic processes, and origin of landslides with their contribution to denudation rates. Also, current biomorphodynamics (uprooting process) has not been sufficiently studied.

Este trabalho objetiva compreender o quadro geomorfológico da porção terminal do baixo curso do rio Paraíba do Norte – PB, mediante a classificação e diferenciação cartográfica das unidades de relevos presentes na área de estudo. Adotou-se para o presente trabalho a escala de 1:25.000 que permitiu identificar os seis táxons propostos na metodologia de Ross (1992). O estudo possibilitou conhecer com maior nível de detalhe a geometria e os padrões de relevo existentes na região, onde se destacaram áreas de acumulação e denudação, dentre elas: planícies marinhas, fluviais e flúvio marinhas, formas de terraços e vertentes, falésias, praias, barras arenosas, bancos de areia, paleolinhas de praias, recifes, lagoas antropogênicas, lagunas, dolinas e glacis de sedimentação, além de formas de relevos tabulares e convexos que modelam os tabuleiros litorâneos da costa paraibana.

The restoration of the denudation thickness is the basis for quantitatively analyzing the basin burial history, thermal evolution history and hydrocarbon accumulation conditions. The well data is not sufficient to do this in the southern Lishui Sag with only 5 wells, so the new, high-quality three-dimensional (3D) seismic data is essential. The methods employed to determine the eroded thicknesses of key unconformities in the study area are the mudstone acoustic time difference (AC) method, vitrinite reflectance (Ro%) method and stratigraphic trend comparison method. On the basis of the structural evolution, the restoration of the paleogeomorphology is carried out. The results show that the Wenzhou formation (E2w) in the entire study area has been all denuded. The denudation thickness is in the range of 0-550 m, and decreases gradually from west, thicker than 200 m, to east. The erosion of the upper Lingfeng formation (E11) are mainly occurred in the N-P-1 structural trap (N-P-1), the N-P-2 structural trap (N-P-2) and the N-P-3 structural trap (N-P-3). Among them, the eroded area in N-P-1 (near well S-1) and N-P-2 is 200-230km2, and the denudation thickness is 0-600m, which increases from south to north, even up to 200-400m in the region around well S-1. In N-P-3, the extent of denudation is 30-50 km2, and the denudation thickness is 0-400m. In the early stage of the upper E11, one north-south strike slip fault began to develop in the southern study area. Affected by this fault, the southern Lingfeng bulge was offset, forming a gorge, and the eastern and western sides of the concave belt connected to each other. On the basis of the paleo-geomorphological characteristics, it is shown that the sedimentary center of the west subsag began to migrate to the south.

IF 4.40; Q1); International audience; An emerged coral reef terrace sequence flanks the northern coast of Sumba Island in Indonesia. The sequence was created by the joint effects of uplift and Quaternary sea level oscillations. Since its emergence, it undergoes chemical erosion, which is facilitated by its carbonate lithology. The morphology is dissected by multiple catchments drained by deep canyons, whose stream profiles display several knickpoints. We applied a multi-methods approach using high-resolution topographic data (Pleiades imagery), geomorphological analysis and denudation rates derived from 36Cl cosmogenic nuclide concentrations to characterize the dynamics of these coastal drainages. We specifically investigate (1) the channel response to eustatic forcing, by analyzing knickpoint dynamics along a longitudinal river profile, and (2) the control of internal and external forcing over the catchment-scale erosion. Firstly, knickpoints form at the distal edge of the emergent reef at each regressive stage following a sea level highstand. The knickpoint propagates and rotates upward by regressive erosion. Knickpoint propagation rate decreases sharply over time until it becomes negligible before the next sea-level rise, which implies a marked decline in knickpoint retreat rate before its resorption. We attribute the inability of the river at Cape Laundi to fully propagate eustatic oscillations to its low stream discharge and low sediment supply, related to its small drainage area, to the karstic nature of the coral reef terraces composing the sequence, and to the high frequency of eustatic forcing. Secondly, average denudation rates calculated from 36Cl cosmogenic nuclide concentrations of sands collected at the outlet of five catchments draining the sequence amount to 69 ± 8 mm·ka−1. We emphasize the role of canyon areas in driving the denudation of the major catchments. However, no first-order correlation has been observed between catchment metrics, uplift rates and denudation rates. Finally, our correlations between catchment finite eroded volumes and uplift rates highlight the tendency of catchments to widen with low uplift rate and to lengthen while incising the sequence deeply with higher uplift rates.

International audience; Transient evolution and adjustment to changing tectonic and climatic boundary conditions is an essential attribute of landscapes, and characterizing transient behavior is a key to understanding their dynamics and history. Developing new approaches to detect such transience has been explored by various methods, in particular to identify landscape response to Late Cenozoic and Quaternary climatic changes. Such studies have often focused on regions of high relief and/or active tectonic activity where interferences between tectonic and climatic signals might complicate the interpretation of the observations. We investigated the case of the hillslopes of the Serra do Cipó quartzitic range in SE Brazil in order to detect and quantify transience in a tectonically quiescent landscape over 100-ka timescales. We determined hilltop curvature from a high-resolution digital surface model derived from Pléiades imagery and measured cosmogenic nuclide (10Be and 26Al) concentrations at these hilltop sites. We compare both observations with predictions of hillslope diffusion theory, observing a distinctive signature of an acceleration of denudation. We performed a joint inversion of topographic and isotopic data to retrieve an evolution of the hillslope sediment transport coefficient through time. The timing of the increase in denudation cannot be unequivocally associated with a single climatic event but is consistent with important, climatically modulated fluctuations in precipitation and erosion in this area during the Middle and Late Pleistocene.

International audience; Assessing rivers' and hillslopes' sensitivity to external forcing is paramount to understand landscape evolution, in particular as a response to Quaternary climate changes. River networks are usually considered to be the main conveyors of environmental signals, such as changes in precipitation, temperature, or baselevel. Yet because hillslopes provide the source of sediment for river networks, their response to environmental change also modulates landscape dynamics. In order to characterize such behavior, we analyze the response times of a transport-limited hillslope. We use simple numerical models of denudation to study hillslope responses to oscillatory forcing and understand their filtering effects on environmental signals. Modifications in the frequency of climate oscillation, such as the change that occurred at the Mid-Pleistocene Transition, can significantly modulate hillslope sediment-flux response. We infer a wide range of hillslope responses, ranging from negligible change over the full range of climate-forcing frequencies, to a significant filtering of long-period signals.

We present a 3D reconstruction of ice thickness distribution across the New Zealand Southern Alps at the Last Glacial Maximum (LGM, c. 30–18 ka). To achieve this, we used a perfect plasticity model which could easily be applied to other regions, hereafter termed REVOLTA (Reconstruction of Volume and Topography Automation). REVOLTA is driven by a Digital Elevation Model (DEM), which was modified to best represent LGM bed topography. Specifically, we removed contemporary ice, integrated offshore bathymetry and removed contemporary lakes. A review of valley in-fill sediments, uplift and denudation was also undertaken. Down-valley ice extents were constrained to an updated geo-database of LGM ice limits, whilst the model was tuned to best-fit known vertical limits from geomorphological and geochronological dating studies. We estimate a total LGM ice volume of 6,800 km3, characterised predominantly by valley style glaciation but with an ice cap across Fiordland. With a contemporary ice volume of approximately 50 km3, this represents a loss of 99.25% since the LGM. Using the newly created ice surface, equilibrium line altitudes (ELAs) for each glacier were reconstructed, revealing an average ELA depression of approximately 950 m from present. Analysis of the spatial variation of glacier-specific ELAs and their depression relative to today shows that whilst an east-west ELA gradient existed during the LGM it was less pronounced than at present. The reduced ELA gradient is attributed to an overall weakening of westerlies, a conclusion consistent with those derived from the latest independent climate models.

This paper focuses on the Landquart drainage basin, where we explore geomorphic signals related to the spatial differences in bedrock lithology and differential uplift. We use concentrations of cosmogenic 10Be to quantify the sediment flux patterns in the region. Furthermore we use the chemical composition of the fine fraction (

Dolines are small to intermediate enclosed depressions and are the most numerous karst feature in Slovenia. They are circular in plan form and vary in diameter from a few metres to over a kilometre. They are developed in limestone, dolomite, carbonate breccia and conglomerate and occupy different geomorphic settings. They were formed by various processes like dissolution, collapse, suffosion and transformation of caves to surface features by denudation. Publicly accessible lidar data, provided by a nationwide laser scanning project of Slovenia, was used for this study. To catalogue the dolines, we manually label a fraction of the digital elevation model (DEM) with a binary mask indicating if the area is a doline or not. We then train a slightly modified u-net, a type of machine learning algorithm, on the labelled territory. Using the trained algorithm, we infer the binary mask on the entire DEM. We convert the resulting mask into an ESRI Shapefile and manually verify the results. We note that the training and inference are error prone on types of relief that were less common in the training set (e.g., the relatively uncommon collapse dolines). We believe manual verification mitigates most of these errors, so the resulting map is a good basis for the doline study. We have made our georeferenced catalogue of dolines available at https://dolines.org/ (Mihevc & Mihevc 2021). Dolines are found in most of the karst areas, except mountains where they were eroded by glacial action or covered by glacial deposits. We detected 471,192 dolines and divided them into three genetic types. Most abundant are solution dolines (470,325). The average doline is 9 m deep, has a diameter of 42 m and a volume of 14,098 m3. The density of dolines on levelled surfaces can be as high as 500/ per km2. They are absent from the floors of poljes and steeper slopes, and are less abundant on sloping surfaces. We have identified 314 dolines to be of collapse origin. The mean depth of collapse dolines is 49 m, and 20 of them are deeper than 100 m. The mean volume is 1.2 million m3, with the largest having a volume of 11.6 million m3. Most of the collapse dolines can be found close to ponors or springs or corridors where large underground rivers flow. We have detected 553 suffosion dolines formed by suffosion of sediments in blind valleys or on poljes. This basic data set for dolines enables further study and comparison of dolines with the geology and topography of the karst.

Transient evolution and adjustment to changing tectonic and climatic boundary conditions is an essential attribute of landscapes. We present a new approach to detect and quantify transience in slow erosion landscapes over 100 ka timescales. We compare curvature and cosmogenic nuclides measurements (10Be and 26Al) at hilltop sites with predictions of hillslope diffusion theory, in the slowly evolving quartzitic Serra do Cipó range in SE Brazil, and we observe a distinctive signature of an acceleration of denudation. The timing of this increase cannot be unequivocally associated with a single climatic event but is consistent with climatically-modulated important fluctuations in precipitation and erosion in this area during Middle and Late Pleistocene.

Inselbergs, such as Uluru in central Australia, are iconic landscape features of semi-arid and deeply denuded continental interiors. These islands of rock are commonly skirted by steep, overhanging cliffs (flared slopes) at ground level. The weathering processes responsible for formation of flared slopes and steep-sided inselbergs in flat, planated landscapes are enigmatic. One model emphasizes sub-surface weathering followed by denudation and excavation of saprolite to expose the unweathered bedrock while other models advocate slope development under subaerial conditions at ground level. We present a new hypothesis that identifies wildfire as a primary agent of flared slope development via fire-induced rock spalling around the periphery of inselbergs. Widespread fire-spalling following the 2019–2020 Australian fires illustrates that this is a common form of physical weathering in fire-prone environments but its effects are particularly evident in semi-arid regions where lateral fire-spalling dominates over fluvial and chemical weathering to create flared slopes and steep-sided inselbergs., Fire is an important mechanism of physical weathering responsible for the formation of overhanging flared slopes around the margins of steep-sided inselbergs. Fire-spalling erodes landscapes laterally rather than vertically and produces significant volumes of new sediment.

Topographic development via paraglacial slope failure (PSF) represents a complex interplay between geological structure, climate, and glacial denudation. Where debris generated by PSFs is deposited on the surface of a glacier, this debris can increase the extent or thickness of a supraglacial debris-cover, in turn modifying glacier ablation and affecting meltwater generation. To date, little attention has been paid to intensity and frequency of PSFs in glacierised, monsoon temperate regions of Southeast Tibet. We mapped PSFs along the 5 km-long, west-east trending ice tongue of Hailuogou Glacier (HLG), Mt. Gongga, using repeat satellite- and UAV-derived imagery between 1990 and 2020. Three types of PSF were identified: (A) rock fall, (B) sediment-mantled slopes slide and collapse, and (C) gully headwards erosion. We analyzed the formation, evolution and current state of these PSFs and discuss these aspects with relation to glacier dynamics and paraglacial geomorphological history. South-facing slopes (true left of HLG) showed more destabilization and higher PSF activity than north-facing slopes. We observed annual average rates of downslope sliding for type B PSFs of 1.6–2.6 ± 0.04 cm d−1, whereas the average upward denudation rate for type C PSFs was 0.7–3.39 cm d−1. We show that type A PSFs are non-ice-contact rock collapses that occur as a long-term paraglacial response following glacier downwasting and the exposure of steep rocky cliffs and which could also be influenced by precipitation, freeze-thaw cycling, earthquakes or other factors. In contrast, type B and C PSFs are a more immediate response to recent glacier downwasting. We further argue that the accelerating downwasting of glacier are used as a preparatory or triggering factor, which could directly or indirectly cause the PSFs.

Denudation rates are routinely derived from concentrations of terrestrial in situ produced cosmogenic nuclides (TCN), particularly from 10Be concentrations in river sand. Denudation rates are calculated assuming that they remain steady throughout the integration time scale of the TCN. However, such an assumption is possibly unverified in settings with negligible tectonics, where rates typically range from 10 to 100 mm/ky. In those settings, the TCN conveys a signal that integrates denudation over a time span longer than a few thousand years. The signal may include periods when anthropogenic and climatic forcing on denudation was distinct from modern times. For instance, agricultural practices were limited before 6,000 years B.P. and climatic conditions were colder and drier before 10,000 years B.P. A variable forcing may produce variable and transient denudation rates. In that case, the assumption of steady denudation rates is invalid, and their derivation may introduce a bias.To detect transient landscapes and resolve such a bias, we can take advantage of the different sensitivity of the 14C and 10Be TCNs to recent and short-term changes in surface denudation. In situ 14C is more sensitive than 10Be to such changes, because of a shorter half-life (5,700 y compared to 1.4 My). This potential application of coupled 14C - 10Be measurements has recently been discussed in several theoretical studies (Hippe, 2017; Mudd, 2017; Skov et al., 2019). Despite the improvement of 14C extraction lines and measurement facilities (Hippe et al., 2009; Lupker et al., 2019), sensitivity tests remain limited on natural cases (Hippe et al., 2012).Here, we propose assessing this new application by in situ 14C - 10Be measurements on river sand from the Cevennes and the Monts Margeride within the Variscan Massif Central in France. With an average elevation of ~700 m, this mountain range presents an asymmetrical topography, composed of a low-relief surface reaching 1,700 m, and bordered by a gently sloping flank to the west and a steep escarpment to the southeast, along the Cevennes fault. This escarpment receives frequent and seasonal extreme precipitation events (300-700 mm in 48h) on its southeast flank.The range is subject to very limited seismic activity and appears relevant for an application of the 14C-10Be couple. Basins are rich in quartz and have homogeneous lithology. The recent paleoclimatic context is well constrained, with substantial climatic variations but with limited Pleistocene glaciations (e.g. Fauquette et al., 1999; Magny et al., 2003; Mayewski et al., 2004). The Massif Central is subject to active erosion processes, without major contribution from stochastic events such as landslides. Denudation rates are in the range of the theoretical study of Skov et al. 2019 (Schaller et al. 2001; Molliex et al. 2016; Olivetti et al. 2016; Desormeaux et al., 2021) and several studies have suggested transient denudation patterns (Schaller et al. 2001; Olivetti et al. 2016). With our new measurements, we will verify whether the 14C-10Be couple has sufficient resolution to detect such transience in natural cases.

International audience; 10 Be-derived catchment-wide denudation rates are positively correlated with topographic indices in the southern Longmen Shan.  Erosion rates are consistent over short-and long-term timescales across the Longmen Shan, suggesting an exhumational steady state.  Rock uplift pattern and topographic evolution across the Longmen Shan have been largely controlled by upper crustal shortening and fault geometry.

The tectonically active Taiwan orogen features numerous rivers that yield a high amount of sediment with fluxes exceeding 104 t/km2/yr. Amongst these, the landslide-dominated Liwu River is well studied regarding its dynamic surface processes. However, the quantification of denudation in the Liwu Basin is still an ongoing task as rates obtained to date are subject to substantial differences depending on methods that differ in their spatio-temporal scales. We constrain an upper limit of global denudation using the cosmogenic nuclide 10Be(meteoric) and its ratio to stable 9Be. Meteoric cosmogenic 10Be is delivered to Earth’s surface by precipitation, whereas stable 9Be is released from rock weathering. In contrast to in situ cosmogenic 10Be measured in quartz, the 10Be(meteoric)/9Be ratio can be analyzed in quartz-poor settings. 10Be(meteoric)/9Be-derived denudation rates (Dmet) vary from 8.1 to >30 mm/yr in the Liwu mainstem, and from 3.4 to 21.5 mm/yr in the tributaries. These new Dmet are among the highest cosmogenic nuclide-derived rates ever measured. Most of these rates agree with rates from sediment gauging or channel incision. We propose that stochastic landsliding plays a major role in denudation processes here. Using a soil-bedrock mixing model and published riverine organic 14C data as a soil tracer, we estimate the fractional contribution of bedrock landslide material to mainstem sediments to be 55%–97%, which explains the magnitude and large variability (4-fold) in Dmet. We demonstrate the complexity associated with denudation rates determination in landslide-dominated routing systems; but also the potential of 10Be(meteoric)/9Be for tracing stochastic landsliding processes., Journal of Geophysical Research: Earth Surface, 126 (10), ISSN:0148-0227, ISSN:2169-9003, ISSN:2169-9011

This article presents characteristics of surficial mass movements after cutting a slope through the Prime National Highway 1 (hereinafter abbreviated as PNH-1) in Bhutan. The surficial mass movement, in the form of slope failures, affects the ability of traffic to move along the PNH-1. The geology in the area of the PNH-1 consists of metamorphic rocks. There are several types of surficial mass movement in slopes, for instance, rock/soil slide, debris flow, and rock falls. Slope failure has occurred due to the geological discontinuities, the boundary of strata, joints, and so on. From the observation of more than 100 slope failures along the PNH-1, we classified the surficial mass movements into three types: “Denudation,” “Erosional flow,” and “Slide.” Among these three types, “Denudation” and “Erosional flow” destabilize the surface layer of the slope after a while after cutting, while “Slide” tends to collapse on the slope within a short time after cutting. According to Varnes’ landslide classification, surficial mass movements such as “Denudation” and “Erosional flow” are categorized as “Flows,” and “Slide” are categorized as “Slides.”

Long-term geomorphology has received little recent attention in Scotland. Palaeosurfaces and major landforms, including valleys and basins, can be linked to the sub-Caledonian and sub-Permian basement unconformities. The present topography was sculpted from the sub-Palaeocene unconformity after kilometre-scale uplift in response to Early Palaeogene magmatism. Recent results from thermochronology indicate an eastward decrease in denudation across Highland Scotland that is supported by landscape persistence in eastern areas since the Devonian. A sequence of planation surfaces developed from the Late Eocene onwards in intervals of slow uplift and high sea levels. The highest extensive surface, the Eastern Grampian Surface, has been uplifted to an elevation of 500–840 m. The surfaces formed by etch processes operating in response to changing base levels under warm-to-cool, humid environments, with extensive forests and widespread deep weathering. After uplift, each planation surface was modified through valley incision, backwearing of scarps and downwearing. Pliocene sea-level fall likely led to formation of coastal platforms that included precursors of the present Hebridean strandflat.

The Middle Permian Maokou Formation in the southeastern Sichuan Basin is a typical carbonate karst reservoir. At the end of the Middle Permian, a short-term tectonic uplift (Tungwu movement) occurred in the upper Yangtze region, causing the formation of dissolved fissures and holes. To determine the location of the high-quality reservoir, this paper calculated the eroded thickness using the Milankovitch theory. Based on the gamma logging data of the six wells in the southeastern Sichuan Basin, the dominant frequency and the astronomical time scale were evaluated via frequency spectrum analysis, continuous wavelet transform, and empirical mode decomposition. In addition, we analyzed the relationship between Fischer curve characteristics and the variation of lithology. Last, four methods were used to calculate the eroded thickness, and the rationality was analyzed. Consequently, we identified four levels of Milankovitch cycles, i.e., middle eccentricity (e2), short eccentricity (e3), long obliquity (o1), and short obliquity (o2). Also, the Fischer curves of the six wells were divided into two forms related to local structural uplift. The residual strata of the Maokou Formation comprised three complete third-order cycles, and the boundaries were the 15th, 34th, and 54th e3 cycles. The deposition rate of bioclastic limestone was the lowest (2.12-5.36 cm/ka with an average of 3.30 cm/ka), whereas the deposition rate of argillaceous limestone was the largest (2.27-5.25 cm/ka with an average of 4.09 cm/ka). Among the four methods, the missing formation deposition rate method exhibited the most precise calculation results, while that of the seismic data method was relatively low. Generally, the eroded thickness of the Maokou Formation in southeastern Sichuan was in the range of 0-140 m, i.e., the eroded thickness in the west and south of X14 was relatively large (>100 m), while the area north of LS1 experienced the weakest denudation (eroded thickness < 40 m).

We compile detrital 10Be concentrations of Alpine rivers, representing the denudation rates pattern for 375 catchments across the entire European Alps. Using a homogeneized framework, we employ state-of-the-art techniques for inverting in-situ 10Be concentrations into denudation rates. From our compilation, we find that (i) while lithologic properties and precipitation/runoff do influence erosion mechanisms and rates at the scale of individual catchments and in some specific Alpine regions, such controls do not directly stand for the entire Alps, (ii) as also previously suggested, catchment-wide denudation rates across the entire European Alps closely follow first-order Alpine topographic metrics at the scale of individual catchments or selected Alpine sub-regions. However, in addition to previous local-scale studies conducted in the European Alps, our large-scale compilation highlights a functional relationship between catchment-wide denudation and mean catchment slope angle. Catchment-wide denudation positively correlates with mean catchment slope up to a threshold angle (25–30°). Above this threshold, any correlation between catchment-wide denudation and slope as well as other catchment metrics breaks apart. We can reconcile these systematic patterns by proposing a regional erosion model based on diffusive-transport laws for catchments located below the slope threshold angle. In oversteepened catchments situated above-threshold slopes, erosion is stochastic in nature, as glacial carving likely caused a partial decoupling between hillslope and fluvial domains with complex topographic relationships and sediment connectivity patterns. Finally, we identify a first-order positive relationship between modern geodetic rock uplift and catchment-wide denudation for the European Alps. The observed spatial pattern is highly variable and possibly reflects the surface response to deep geodynamic mechanisms prevailing in the different Alpine regions. We conclude that today's topography and geomorphic features of the entire Alps are the result of a millenial-scale geomorphic response to past glacial processes and active rock uplift, highlighting a link between external and internal drivers for mountain erosion. ISSN:0012-8252 ISSN:1872-6828

The present study deals with the morphometric quantification of erosion and illustrates the uplift component triggered by denudation (isostasy) in the growth and evolution of a rising orogeny by the application of Airy isostasy concepts. The Gibraltar Arc, located in the Western&ndash, Central sector of the Betic Cordillera, developed an exceptional geological scenario during the Messinian Salinity Crisis since the thin emerged fringe of the uprising Cordillera disconnected the Atlantic and Mediterranean basins, generating a relevant misbalance and asymmetry in the fluvial erosion between the two slopes of the emergent orogeny. Our analysis was applied to 50 individual drainage basins (spatial isostatic units) in the Western&ndash, Central Betic Cordillera, allowing us to obtain individual and bulk estimates for these isostatic parameters. GIS-based numerical estimations were obtained using LiDAR Digital Elevation Models (DEMs) provided by the Spanish Geographical Institute and reconstructed pre-incision surface models obtained from proxy paleo-elevation data, estimated from stratigraphic and geomorphological littoral to shallow marine markers. The obtained values for geophysical relief, denudation plates, erosion/uplift rates and computed accumulated uplift (245&ndash, 407 &plusmn, 20 m) are higher for the ancient Mediterranean slope of the orogen. On the contrary, the Atlantic slope presents an accumulated uplift of only 138&ndash, 236 &plusmn, 20 m, indicating the strong control of the ancient Messinian Atlantic&ndash, Mediterranean water divide. The temporal study of erosion indicates that most of the difference in uplift in the Mediterranean slope was achieved during or soon after the Messinian Salinity Crisis, resulting in mean uplift rates of 0.21 mm/y, but practically null (0.01 mm/y) for the Atlantic slope. The comparison of the geophysical relief models with proxy paleo-elevation data allowed us to assess the current state of the denudation process in the range. The results indicate that, towards the west of the range denudation compensated elevation, and is actively back-feeding isostatic rebound. Therefore, the contribution of external processes to mountain range elevation through isostasy is quantitatively estimated using elevation data. In this case, a relevant part of the surface uplift (50-55%) is undertaken by the orogen. Ultimately, the Messinian Salinity Crisis-related isostatic response to differential denudation may be behind the quaternary westward tilting of Iberia, causing more than 70% of the Peninsula to drain towards the Atlantic.

Thermal denudation is a combination of the processes responsible for the formation of retrogressive thaw slumps (cryogenic earth flows) and thermocirques. Thermocirques are the depressions with a semi-circle shape resulting from tabular ground ice thaw. Environments characteristic of Сentral parts of Yamal and Gydan peninsulas forming the so called Kara sub-latitudinal transect, are favorable to activation of thermal denudation. The key factors are continuous permafrost distribution and shallow occurrence of tabular ground ice.An increase in ground temperature and active layer thickness in 2012-2013 cause the intensification of thermal denudation along Kara sub-latitudinal transect. Field studies in the area of “Vaskiny Dachi” research station as well as remote sensing of 2018 data demonstrates the presence of both active and stabilized thermocirques during.This research presents preliminary results of collecting and analyzing the distribution of more than 400 landforms caused by thermal denudation identified in central Yamal and central Gydan peninsulas. Coastal thermodenudation landforms were not taken into account to exclude the influence of wave erosion in this study. Such work became possible due to free of charge satellite images with a very high spatial resolution available at the service Yandex.Maps (https://yandex.ru/maps/).In Yamal peninsula, we identified 63 active and 53 stabilized thermodenudation landforms, in Gydan peninsula, 169 active and 166 stabilized, respectively. Active thermodenudation features concentrate in the western and southern parts of central Yamal, while stabilized dominate in western and central parts. In central Gydan both active and stabilized features of thermal denudation are located at northwestern part and are distributed more evenly compared to Yamal. Northern border of all identified thermodenudation features for both Yamal and Gydan peninsulas is located at 71 degrees North, and the southern border at 69 degrees North. Despite the difficulties of visual interpretation of thermal denudation features, we defined the majority of them as thermocirques, most of which are located along lake coastlines. Such indication was also confirmed by in-situ data collected during multiyear field campaigns in the study area. These results reveal a prevalence of thermal denudation features in the study area and the collected data gives us an opportunity for spatial analysis of their distribution.The reported study was partially funded by RFBR according to the research project #18-05-60222

Meteorite impact craters are morphologic features that can develop characteristic radial, centripetal, and concentric drainage patterns. With age, fluvial activity denudes this morphologic feature, thereby erasing the evidence of a prominent geologic event. Apart from morphology and age, the target lithology and climate also influence crater denudation. In this study, we derive an index, called the Denudation Index (DI), which is a measure of rim degradation caused by fluvial activity. DI was derived by summing the average of first order drainages that retains radial and centripetal patterns to the total number of streams. DI was obtained through the extraction of drainages from digital elevation models (DEM) for 71 craters formed since the Phanerozoic eon. The DI was correlated with the morphology, age, lithology and paleoclimate. Paleoclimatic data corresponding to each crater was generated by reconstructing the crater paleo-positions through GPlates and superimposing the same to the Scotese's Global Climate Model with an interval of 1 Ma. The study revealed that denudation is more prominent in a complex crater's formation on a crystalline target rock than in simple crater on a sedimentary target. Craters in the equatorial rainy climate are more denudating than other climates. Thus, this study provides a new, rather novel, method of expressing the denudation of a crater. Furthermore, this study shows that the drainage network is a unique signature that can be used for depicting the denudation of morphologic features, especially a prominent one like the meteorite impact crater.

The Mendocino Triple Junction (MTJ) region in northern California is an archetype for studying landscape response to varying rock uplift rates as they increase toward the triple junction. Underpinning these studies lies the assumption that this landscape has reached a dynamic equilibrium in which rock uplift and erosion rates are equal; however, no study has shown that such an equilibrium actually exists around the MTJ region. Here, we report 10Be- and 26Al-derived erosion rates calculated from isotope concentrations in detrital, fluvial sediment from coastal drainage basins; we then compare these rates with uplift rates inferred from marine terraces that were formed and preserved by uplift during the last ∼305 ka. Erosion rates in the more slowly uplifting southern part of the region range from 0.21–0.32 mm/yr and are consistent with rock uplift rates since 305 ka. However, in the northern transition zone, where uplift rates apparently started to increase about ∼100 ka due to northward migration of the MTJ, erosion rates are higher, 0.43 to 0.69 mm/yr. These rates are similar to uplift rates from 96–305 ka, but substantially less than recent uplift rates of ∼3.5–4 mm/yr inferred for the past ∼72 ka. In the central part of the King Range, finite erosion rates cannot be determined due to (i) the presence of excess 10Be that does not appear to have originated from in-situ cosmic-ray production during erosion and transport of the sediment, and (ii) 26Al concentrations below detection limits. The difference between catchment-wide erosion and recent uplift rates in coastal catchments may be related to a lag in response of hillslopes and tributaries to changes in rates of tectonically-driven relative base-level fall or the uncertainties in rock uplift rates inferred from marine terraces. This study suggests that measurements of both erosion and uplift rates are crucial in assessing the equilibrium state of landscapes and in understanding the topographic features made by surface and tectonic processes.

The Western Ghats (WG), a topographic scarp facing towards the west coast of India and extending over diverse geological terranes – Deccan Volcanic Province (DVP), Dharwar Craton (DC) and Southern Granulite Terrain (SGT), is an enigmatic geomorphic feature. WG is characterized by low gravity anomalies. In order to decipher the sources of gravity anomalies, we have decomposed the gravity anomalies using wavelength filter and have obtained estimates of the depth to crust-mantle boundary (CMB) under WG and surrounding regions from the inversion of gravity data, which is compared with seismically determined CMB estimates. Overall, the CMB depth varies from 33 to 50 km, which is consistent with seismically determined values, except in the region of shear zones between DC and SGT probably indicating a different density contrast at CMB. The major source of gravity low is found to be the deepening of CMB under the WG compared to adjacent regions regardless of surface lithology. The CMB depths under WG and surrounding region generally approximate the CMB depths estimated for low strength flexural isostatic models, which suggests that flexural compensation of uplifted topography, later modified by tectonic and denudation processes, is a likely development model for the Western Ghats.

Continuous sediment supply in the Aka-kuzure landslide scar, in the tectonically active alpine Southern Japanese Alps, was investigated using airborne light detection and ranging data in 2000, 2003, 2007 and 2012. In addition, we focused on the spatial variability of denudation patterns based on topographical analyses using DEMs. Denudation volume for the past 12 years reached about 106 m3 and mean annual denudation rate ranged from 0.25 to 0.31 m/yr. Topographical analyses revealed that sediment supply in the scar consists of a combination of two denudation types, sporadic-deep and wide-thin. These denudation types have different roles in the topographical development of the landslide scar. Sporadic-deep type supplies less volume than wide-thin type but still contributes to channel development, as it mainly occurs on lower-order streams and tends to change the convex slope into a concave slope. In contrast, although denudation depth of the wide-thin type is thin, the area affected by this type extends to the whole landslide scar. Consequently, the wide-thin type accounts for most of the total volume lost, for which detachment by frost shattering is suggested as an important role.

O presente trabalho objetivou compreender a importância dos afloramentos graníticos na evolução do relevo da serra do Mar no Paraná. A metodologia se baseou na mensuração dos processos denudacionais utilizando o isótopo cosmogênico 10Be. Os resultados demonstraram que áreas com granitos apresentam taxas de denudação inferiores às registradas em seus entornos. O relevo também influencia nas taxas denudacionais, pois as porções mais rebaixadas das escarpas e de menor declividade proporcionam as maiores taxas de denudação em virtude do maior manto de alteração, proporcionado pelo maior acúmulo de água. As planícies costeiras configuram-se como áreas propícias para a retenção de sedimentos. Deste modo, identificou-se que a associação do contexto litológico com o geomorfológico constituem importantes fatores controladores da evolução da paisagem da serra do Mar paranaense.

This paper considers the results of geomorphological field experiments in Siberia conducted at the permanent stations operated by the V.B. Sochava Institute of Geography SB RAS for a 60-year period and describes the observation methods. A unique database of quantitative data on the modern relief dynamics is provided. The rates of slow mass motions of soils on slopes, and also of the deluvial, aeolian and channel processes are presented. Observations for long-term time series are summarized. Much attention is paid to the results from investigating the slope processes. The contribution of stationary investigations to the solution of fundamental problems in geomorphology is shown. The role of field experiments in understanding the temporal organization of geomorphological systems is emphasized. Dynamic phases of the intrasecular cycles of exogenous relief formation are investigated. Models of the contemporary functioning of denudation systems that cover all possible variety of dynamic phases and morphological and climatic conditions of denudation in semi-arid conditions of southern Siberia are obtained. It was found that the spatial ordering of exogenous relief formation in the south of Siberia is manifested in the form of a regional series of correlative denudational systems whose structure and functioning mode naturally vary along the aridity and continentality vectors of climate. The spatial ordering of aeolian lithostreams is shown, which are involved in a common cycle of matter spinning clockwise and moving aeolian fine material along the northern subarid foothills areas of the mountain belt of Southern Siberia. An important role of the observation results on the relief dynamics for solving ecological problems is pointed out. Prospects for a further development of experimental geomorphological research in Siberia using high-precision instruments, GIS technologies and other modern methods are outlined.

The Gonghe-Guide area, which is located at the northeastern edge of the Qinghai-Tibetan Plateau, has the greatest hot dry rock (HDR) geothermal resources exploration and development potential in China. Separated by the Waligong tectonomagmatic belt, the study area includes the Gonghe and Guide basins, which are characterized by distinctly different thermal state and surface thermal manifestations. Although a number of geophysical explorations have been undertaken, studies on fundamental geothermal theory remain scarce, including a lack of high-quality heat flow determinations and thermal structure studies. In this study, we obtained continuous steady-state temperature logs from three deep boreholes (GR2 and DR3 in the Gonghe basin and ZR1 in the Guide basin). The thermal conductivities and radiogenic heat production rates of the outcrop samples gathered from the two basins were measured. The heat-flow values were determined to be 116.3–122.3 mW m−2 for the Gonghe basin, yielding a mean of 119.3 mW m−2. Two existed heat flow sites (R2 and R3 boreholes) gave an average heat flow of 75 mW m−2 for the Guide basin, which is approximately that of the regional background heat flow level of the northeastern Tibetan Plateau. The 1-D theoretical crustal thermal structures of the Gonghe and Guide basins were constructed by solving steady-state heat conduction equation. The results show that the Moho temperature and mantle heat flow in the Guide basin were 1016 °C and 27 mW m−2, respectively. However, the temperature field in the Gonghe basin indicated partial melting in the crust. The high temperatures and thus heat flow in the Gonghe basin may suggest the existence of anomalous heat source body in crust. Successful inversions of vertical and horizontal temperature variations of boreholes in the Gonghe basin were obtained by numerically simulating a cooling rectangular magma chamber with a buried depth of 5–6 km and horizontal dimensions of 12–14 km. The study emphasizes that the anomalous heat flow in the Gonghe basin may be the joint thermal effect of: (1) the high regional background heat flow level of the northeastern Tibetan Plateau, which is mainly due to the radiogenic heat of thickened crust; (2) the cooling of a shallow magma chamber, which may be caused by the uplift and denudation of the plateau.

The bare karst surface in the southeastern part of Krk Island (Croatia) is characterized by different surface karst features, such as valley-like shallow linear depressions and partially or fully sediment-filled depressions of various shapes and sizes. They were noticed due to locally increased thickness of sediment and enhanced vegetation but had not yet been systematically studied and defined. Considering only the geometry of the investigated surface features and the rare traces of cave environments detected by field surveys, it was unclear which processes (surface karstification and/or speleogenesis) contributed most to their formation. The low-frequency ground penetrating radar (GPR) method using a special 50 MHz RTA antenna was applied to study and describe these karst features. Three study sites were chosen and 5 km of GPR profiles were positioned to include various surface features. The results obtained from the GPR investigation lead to the following conclusions: (1) an increased thickness of sediment was detected in all the investigated depressions indicating their considerable depth; (2) areas between different depressions expressed as attenuated zones in GPR images reveal their interconnection; (3) transitions between surface and underground features are characterized by a collapsed passage visible in the GPR data; and (4) an underground continuation of surface valley-like depressions was detected, proving the speleogenetic origin of such features. Subsurface information obtained using GPR indicates that the valley-like depressions, irregular depressions completely or partially filled with sediment, and some dolines are associated with a nearly 4 km-long unroofed cave and developed as a result of karst denudation. In the regional context, these results suggest long-lasting karstification processes in the area, in contrast to the pre-karstic fluvial phase previously assumed to have occurred here. This research is the first application of the GPR method to survey unroofed caves worldwide and the first detailed study of such karst features in Croatia. The low-frequency GPR proved to be an efficient method not only for detecting underground continuations but also for distinguishing and identifying surface features and transition zones between surface and subsurface segments of unroofed caves and can therefore be used for recognizing similar geomorphological features.

Lateral and vertical erosion at meander bends in the Kentucky River gorge area has created a series of strath terraces on the interior of incised meander bends. These represent a chronosequence of fluviokarst landscape evolution from the youngest valley side transition zone near the valley bottom to the oldest upland surface. This five-part chronosequence (not including the active river channel and floodplain) was analyzed in terms of the landforms that occur at each stage or surface. These include dolines, uvalas, karst valleys, pocket valleys, unincised channels, incised channels, and cliffs (smaller features such as swallets and shafts also occur). Landform coincidence analysis shows higher coincidence indices (CI) than would be expected based on an idealized chronosequence. CI values indicate genetic relationships (common causality) among some landforms and unexpected persistence of some features on older surfaces. The idealized and two observed chronosequences were also represented as graphs and analyzed using algebraic graph theory. The two field sites yielded graphs more complex and with less historical contingency than the idealized sequence. Indeed, some of the spectral graph measures for the field sites more closely approximate a purely hypothetical no-historical-contingency benchmark graph. The deviations of observations from the idealized expectations, and the high levels of graph complexity both point to potential transitions among landform types as being the dominant phenomenon, rather than canalization along a particular evolutionary pathway. As the base level of both the fluvial and karst landforms is lowered as the meanders expand, both fluvial and karst denudation are rejuvenated, and landform transitions remain active.

Production rates are a cornerstone of in situ cosmogenic nuclide applications, including surface exposure dating, erosion rate/denudation rate estimates, and burial dating. The most common approach for estimating production rates is to measure cosmogenic nuclide samples from sites with independently well-constrained exposure histories. In addition, while researchers attempt to minimize the effects of erosion through careful site and sample selection, it can be present at some unknown level in certain sites. We present a general Bayesian methodology for combining information from the nuclide concentrations, the exposure history, and the possibility of erosion, to determine the production rate at a given site. Then, we use another Bayesian approach to combine the results from the various sites. Cosmogenic 3 He is an ideal test-bed for our Bayesian approach. It has the most calibration sites of the commonly measured cosmogenic nuclides, and there is evidence for the effect of erosion on some of the sites. Our approach largely reconciles previous discrepancies between sites of widely varying age, even at latitudes where geomagnetic effects are significant. With the canonical Lal/Stone scaling scheme, we derive a global sea level high latitude 3 He production rate of 118 ± 2 atoms g −1 yr −1 when considering olivine and pyroxene together. Using the Lifton–Sato–Dunai scaling scheme yields a similar rate of 121 ± 2 atoms g −1 yr −1 . Uncertainties associated with these values are improved over previous studies, due to both reduced scatter among the sites and an approach to combining sites which deemphasizes outliers.

The Penmarc’h granitic coastal domain, SW Brittany (Western France), offers the opportunity to address the little investigated issue of erosional processes in a granitic coastal context. From land to sea, the granitic coast is composed of 1) an aerial marine terrace ( 10 Be) analyses, supplies new constraints on the weathering and denudation processes recorded by the Penmarc’h platform in Quaternary times. The role of at least two denudation events is emphasized: (i) a >1.8 m-thick level of granitic material is assumed to have been removed by erosion during the MIS5 sea-level highstand, both in the offshore domain and in the low part of the marine terrace; (ii) an additional 0.6 m-thick level of the granitic substratum was later removed during the last Holocene transgression, mainly in the marine domain. The lack of any morphological step between the subaerial marine terrace and the shore platform is here attributed to the combined effect of multiple factors, including (i) a Quaternary tectonic quiescence, (ii) a major eustatic transgression (MIS5) shaping both the shore platform and the low part of the marine terrace, (iii) the mechanically strong behaviour of the granitic basement with regard to erosion, and (iv) the moderate influence of the Holocene sea-level stillstand (since 6 ka) on the shore platform. Thanks to 10 Be content analysis, a range of vertical erosion rates of ca. 3–6 m⋅Ma −1 is obtained for the onshore domain, showing no discernable difference between the intertidal and aerial erosion rates. From that result, it is thus determined that the long-term development of the Penmarc’h granitic shore platform was mainly driven by marine erosive processes during the MIS5 and Holocene marine transgressions, whereas subaerial erosive processes prevailed after the MIS5 event.

Badlands in Central Istria share a very frequent characteristic with other worldwide badland sites, the rapid erosion rate. Rock wall retreat measurement on such a relief is associated with all types of problems because a certain effort has to be put into the measurement equipment design. Spear vegetation and a few previous studies encouraged the testing of different photogrammetric technologies and data acquisition methods for the determination of the denudation rate in Istrian badlands. The main aim of this paper is the establishment of the most suitable methodological combination for the determination of the badland denudation rate, which is the gully rock wall retreat rate. The photogrammetric approach was tested by measuring and comparing the amount of denudation on the test site, which was established on a gully sidewall. The photogrammetric measurement was used twice within one year. The analysis of the photogrammetric technologies and data acquisition methods focused on the field and laboratory equipment and the accuracy and difference models obtained from the test site measurements. The analysis shows that the combination of digital photogrammetry and fully automatic matching data acquisition provides the most suitable measurement technique of the rock wall retreat in Central Istria badlands and other similar badlands.