Search Results (56)

Extensive radar investigations, observed spectral signatures, geomorphological, and paleoclimate modeling support the presence of mid- to low-latitude ground ice on Mars. The presence of near-surface ice and glacial features has been proposed in Ismenius Lacus, but the ice composition and age remain unconstrained. Our high-resolution stereoscopic analysis reveals distinctive landforms, including sharp-edged polyhedra, chevron patterns, and en-echelon open fractures, indicative of plastic glacial deformation. Current climatic conditions may support year-round ice stability, while sharp-edged polyhedra, open fractures, and the absence of superposed craters suggest active glaciation. The Ariguani delta system lacks fluvial signatures but aligns with glacial erosional and depositional processes. Unlike terrestrial glaciers, ice accumulation here is likely driven by escarpment-fed melt from seasonal permafrost thawing under lithostatic pressure, generating neo-glacial flows that sustain the glacial tongue. This mechanism can also explain regional features, including U-shaped valley subsidence, gravitational slides, flow of low-viscosity material lobes, and ring-mold craters. Thus, we propose sharp-edged polyhedra as diagnostic markers for identifying ongoing ice dynamics on Mars, enabling future automated detection of active glacial environments. Full article

This study investigates the Holocene evolution of the Laraquete-Carampangue strandplain on the tectonically active coast of south-central Chile using ground penetrating radar and light detection and ranging data. The Laraquete-Carampangue strandplain, on the tectonically active coast of south-central Chile, is a rare accretionary feature in a region dominated by rocky shorelines and limited sediment supply. The light detection and ranging data-derived digital elevation model reveals a complex geomorphology comprising 52 beach ridges, aeolian dunes, and fluvial paleochannels, while ground penetrating radar radargrams uncover marine and aeolian facies influenced by past seismic and climatic events. We interpret these units in the frame of past seismic and climatic events. Our geomorphological and stratigraphic findings suggest that the strandplain progradation was driven by relative sea-level changes associated with Holocene seismic cycles and climate change. We propose that the transition from drier to humid conditions in the late Holocene triggered the onset of dune formation at the end of the Little Ice Age. This integrated approach highlights the interplay of tectonic and climatic forcings in shaping coastal landforms, offering insights into their long-term response to environmental change. Full article

The Chacopampean Plain is a major physiographic unit in Argentina, bounded by the Colorado River to the south, the Sierras Pampeanas and Subandinas to the west, and the Paraná River, Río de la Plata Estuary, and the Argentine Sea to the east. Its subsurface preserves sediments from the Miocene marine transgression, while the surface hosts some of the country’s most productive soils. Two main geomorphological domains are recognized: fluvial systems dominated by alluvial megafans in the north, and aeolian systems characterized by loess accumulation and wind erosion in the south. The southern sector exhibits diverse landforms such as deflation basins, ridges, dune corridors, lunettes, and mantiform loess deposits. Despite their regional extent, the origin and chronology of many aeolian features remain poorly constrained, as previous studies have primarily focused on depositional units rather than wind-sculpted erosional features. This study integrates remote sensing data, field observations, and a synthesis of published chronometric and sedimentological information to characterize these aeolian landforms and elucidate their genesis. Our findings confirm wind as the dominant morphogenetic agent during Late Quaternary glacial stadials. These aeolian morphologies significantly influence the region’s hydrology, as many permanent and ephemeral water bodies occupy deflation basins or intermediate low-lying sectors prone to flooding under modern climatic conditions, which are considerably wetter than during their original formation. Full article

The semi-automated extraction of flat surface landforms was carried out, merging a GIS tools application and a geomorphic analysis. The study focuses on seven areas in southern Italy, characterized by different physical landscapes, using a 5 m resolution digital elevation model (DEM). The GIS application allowed the selection of polygonal areas of flat surfaces from diverse arrays of landforms and was implemented using a filtering process to minimize noises. Subsequently, the mean elevation and mean slope of the detected surfaces were extracted and visualized using scatter plots, which helped in determining the elevation ranges and average slope angles for various flat-floored and terraced surfaces. To enhance the reliability of the results, a detailed geomorphic analysis and field survey were conducted to differentiate between fluvial and marine flat surfaces across different physical landscapes. This comprehensive approach included statistical analyses and comparisons with the existing literature to validate the identified flat surfaces, ensuring the accuracy and reliability of the semi-automated extraction procedure. The integration of GIS technology with field investigations not only streamlines the detection of flat landforms but also contributes to a deeper understanding of their geomorphic characteristics, ultimately enhancing geomorphic analysis efficiency. Full article

The semi-automated extraction of landforms using GIS analysis is one of the main topics in computer analyses. The use of digital elevation models (DEMs) in GIS applications makes the extraction and classification procedure of landforms easier and faster. In the present paper, we assess the accuracy of semi-automated landform maps by means of a comparison with hand-made landform maps realized in the Pleistocene Agri intermontane basin (southern Italy). In this study, landform maps at three different scales of 1:50,000, 1:25,000, and 1:10,000 were used to ensure a good level of detail in the spatial distribution of landforms. The semi-automated extraction and classification of landforms was performed using a GIS-related toolbox, which identified ~48 different landform types. Conversely, the hand-made landform map identified ~57 landforms pertaining to various morphogenetic groups, such as structural, fluvial, karst landforms, etc. An overlap of the two landform maps was produced using GIS applications, and a 3D block diagram visualization was realized. A visual inspection of the overlapping maps was conducted using different spatial scales of patch frames and then analyzed to provide information on the accuracy of landform extraction using the implemented tools. Full article

The Münchberg Gneiss Complex (Central European Variscides, Germany) is separated by a deep-seated lineamentary fault zone, the Franconian Lineamentary Fault Zone, from its Mesozoic foreland. The study area offers insight into a great variety of landforms created by fluvial and mass wasting processes together with their bedrocks, covering the full range from unmetamorphosed sediments to high-grade regionally metamorphic rocks. It renders the region an ideal place to conduct a study of compositional and numerical geomorphology and their landscape-forming indices and parameters. The landforms under consideration are sculpted out of the bedrocks (erosional landforms) and overlain by depositional landforms which are discussed by means of numerical landform indices (LFIs), all of which are coined for the first time in the current paper. They are designed to be suitable for applied geosciences such as extractive/economic geology as well as environmental geology. The erosional landform series are subdivided into three categories: (1) The landscape roughness indices, e.g., VeSi_val (vertical sinuosity—valley of landform series) and the VaSlAn_alti (variation in slope angle altitude), which are used for a first order classification of landscapes into relief generations. The second order classification LFIs are devoted to the material properties of the landforms’ bedrocks, such as the rock strength (VeSi_lith) and the bedrock anisotropy (VaSlAn_norm). The third order scheme describes the hydrography as to its vertical changes by the inclination of the talweg and the different types of knickpoints (IncTal_lith/grad) and horizontal sinuosity (HoSi_lith/grad). The study area is subjected to a tripartite zonation into the headwater zone, synonymous with the paleoplain which undergoes some dissection at its edge, the step-fault plain representative of the track zone which undergoes widespread fluvial piracy, and the foreland plains which act as an intermediate sedimentary trap named the deposition zone. The area can be described in space and time with these landform indices reflecting fluvial and mass wasting processes operative in four different stages (around 17 Ma, 6 to 4 Ma, <1.7 Ma, and <0.4 Ma). The various groups of LFIs are a function of landscape maturity (pre-mature, mature, and super-mature). The depositional landforms are numerically defined in the same way and only differ from each other by their subscripts. Their set of LFIs is a mirror image of the composition of depositional landforms in relation to their grain size. The leading part of the acronym, such as QuantSan_heav and QuantGrav_lith, refers to the process of quantification, the second part to the grain size, such as sand and gravel, and the subscript to the material, such as heavy minerals or lithological fragments. The three numerical indices applicable to depositional landforms are a direct measurement of the hydrodynamic and gravity-driven conditions of the fluvial and mass wasting processes using granulometry, grain morphology, and situmetry (clast orientation). Together with the previous compositional indices, the latter directly translate into the provenance analysis which can be used for environmental analyses and as a tool for mineral exploration. It creates a network between numerical geomorphology, geomorphometry, and the E&E issue disciplines (economic/extractive geology vs. environmental geology). The linguistics of the LFIs adopted in this publication are designed so as to be open for individual amendments by the reader. An easy adaptation to different landform suites worldwide, irrespective of their climatic conditions, geodynamic setting, and age of formation, is feasible due to the use of a software and a database available on a global basis. Full article

This study aimed to (1) determine the environmental risk resulting from the contamination of river valley sediments with trace elements of anthropogenic origin, (2) assess the relationship between this environmental risk and the geomorphology of the valley, and (3) identify areas that may become a source of contamination. This research was conducted in the Vistula River Valley between Sulejów and Kazimierz Dolny (Poland). Geochemical and ecotoxicological indices (for fraction < 1 mm) were analyzed (EF, I_geo, PI, CF, C_d, PI_Sum, PI_Avg, PI_Nemerow, PLI, ER, RI). Geomorphological mapping, supported by DEM and remote sensing analysis, was performed. High concentrations of trace elements in sediments, as determined by the ICP-OES and ICP-MS methods throughout the study area, indicate generally high environmental degradation and a moderate-to-considerable ecological risk. Contamination differs in the sediments of individual landforms: the highest levels are found in the sediments of the contemporary floodplain and oxbow lakes, while the lowest are observed in the Pleistocene terrace sediments. Only high concentrations of As, Pb, Zn, and Cd are of anthropogenic origin. Their source is probably the mining area of Upper Silesia (As, Pb, Zn) and agricultural activity (Cd). The differences in the values of geochemical indices in individual landforms confirm the influence of fluvial processes on the distribution of trace elements. Full article

The Ebinur Lake Basin is a typical terrestrial sedimentary Basin in Northwest China that has developed a piedmont distributive fluvial system (DFS) sedimentary environment, lake sedimentary environment, and desert sedimentary environment. The Ebinur Lake receives the sediments carried by the rivers in the basin and is the regional sedimentary center. In this study, a division scheme of modern sedimentary system tracts in the Ebinur Lake Basin was proposed. According to the landform, sedimentary environment, structure, and sedimentary system types, the Ebinur Lake Basin was divided into five system tracts. The area with high altitude and steep gradients mainly develops the rapid sedimentary system DFS, and the area with the lowest altitude in the region develops the lake sedimentary system. The main action area of climate drought and wind field is the dune sedimentary area. The wind field under the influence of hydrological climate and geomorphology has an important influence on the distribution of the sedimentary system tract. The structure determines the development of different types of sedimentary systems by controlling the topographic fluctuation and sedimentary space. Hydroclimate and geomorphology affect the development of sedimentary systems by controlling the sediment source rate in the sedimentary area. Based on the analysis of the characteristics and distribution of the modern sedimentary system in the Ebinur Lake Basin, a method for determining the level of the sedimentary system of the Ebinur Lake was established together with a plane model of the sedimentary system of the Ebinur Lake, which provides a reference for the study of the sedimentary system of continental basins. Full article

Virtual reality is a technological development that, among others, has revolutionized Earth sciences. Its advantages include an opportunity to examine places otherwise difficult or impossible to access and it may also become an important component of education, fostering a better understanding of processes and landforms, geohazard awareness, and an appreciation of geoheritage. This paper reports on the GeoVT project, which aims to create a platform to build and disseminate Virtual Field Trips (VFTs) focused on geomorphology, natural hazards associated with geomorphological processes, and geoheritage sites. To put the GeoVT project in context, an overview of applications of VR in geosciences is provided. This paper subsequently proceeds with a presentation of the project and the GeoVT Authoring application, which is an innovative platform designed to help teachers and students, followed by brief presentations of a number of VFTs developed within the project. They address themes such as fluvial landforms and valley development, coastal landforms, evidence of past glaciation, coastal erosion, wildfire effects, mud volcanoes, and landslides. Full article

The Pearl River is one of China’s large rivers, the second-largest river and the fourth-longest river in China. Its unique geography, landform, and climate conditions create unique fluvial geomorphological processes. Affected by human activities and climate change, the fluvial geomorphological processes in the Pearl River Basin have undergone significant changes in recent decades, seriously affecting the river’s sustainable development. This paper critically reviews changes in fluvial geomorphological processes and analyzes influencing factors in the Pearl River Basin with a focus on possibilities for policy overhaul and strategic adjustments. Full article

The formation of the Jinsha River drainage is a significant subject of concern in the geological and geomorphological fields. Among them, one key question is whether there was a regional paleo lake into which Lower Jinsha River drainage drained during the late Pliocene to early Pleistocene, due to massive fluvio-lacustrine sediments widely distributed in the Lower Jinsha River. Nevertheless, there has yet to be a consensus on the genesis of those fluvio-lacustrine sediments due to poor sedimentological and chronological data. In this study, to unravel the origin of those fluvio-lacustrine sediments and the formation model of the Lower Jinsha River, sedimentary characteristics, including spatial distribution, lithological composition, and stratigraphic contact relationship of those fluvio-lacustrine sediments were analyzed, and chronological determination of the fluvio-lacustrine sediments using Electron Spin Resonance and Optically stimulated luminescence method was conducted. The results show that in the Lower Jinsha River, the lacustrine sediments are mainly composed of silt and clay, with apparent horizontal bedding, stacked with fluvial cobble-gravel and sand, and are in unconformable contact with the underlying bedrock strata or paleo soil. The lacustrine sediments are spatially discontinuous and mainly distributed in the Shigu, Taoyuan, Panzhihua, and Longjie reaches. Downstream of these reaches are deeply incised gorges with an average slope >30°, and many landslide landforms and deposits can be identified here. In each reach, the lacustrine sediments were closely distributed along the trunk and tributary channels in the plane and were distributed at different altitudes, forming a sequence of lacustrine terraces. Chronological analysis shows that in different reaches, the deposition ages of lacustrine sediments are significantly different. In each reach, the deposition age of the lacustrine terraces of high altitude is older than that of low altitude. The above characteristics collectively indicate that the lacustrine sediments in the Lower Jinsha River were locally deposited by individual dammed lakes, probably induced by landslide rather than a regional paleo lake by tectonic activities. During the incision process of the river valley, landslides continuously block the river channel, forming dammed lakes, and then deposited lacustrine sediments at different elevations, forming lacustrine terraces. The lacustrine sediment of the topmost lacustrine terrace in Panzhihua reach was dated to be 1.78 Ma, combined with previous studies on the fluvial terraces, indicating the Lower Jinsha River existed and started to incise its valley before the early Pleistocene. The widespread dammed lake sediment indicates that the formation of the Jinsha River valley follows the pattern of “incision-landslide-damming-aggradation-incision”. Full article

The origin and dynamics of a 2010 pluvial flood in the valley of a large European river are described. In order to study how local people perceive this catastrophic event a small administrative unit (rural municipality) within the Holocene floodplain (thus flooded to 90%) was chosen. Using a questionnaire a human-research survey was performed in the field among 287 people living in flood-prone areas. Almost half of the interviewees feel safe and do not expect a flood recurrence (interpreted as a levee effect). Seventeen percent believe the levee was intentionally breached due to political issues. Six percent of interviewees link the breach with small mammals using levees as a habitat, e.g., beavers, moles, and foxes. The sex and age of interviewees are related to these opinions. Most interviewees (39%) think that flooding was a result of embankment (dyke) instability. The spatial distribution of the survey results are analyzed. Maps presenting: inundation height, economic loss, attitude to geohazards and perception of possible flood recurrence were drawn. Causes of the flood as viewed by local inhabitants and in the context of the riverine geological setting and its processes are discussed. Particular attention is paid to processes linking the levee breach location with specific geomorphic features of the Holocene floodplain. A wide perspective of fluvial geomorphology where erosive landforms of crevasse channels (and associated depositional crevasse splays) are indicators of geohazards was adopted. This distinct geomorphological imprint left by overbank flow is considered a natural flood mark. Such an approach is completely neglected by interviewees who overestimate the role of hydrotechnical structures. Full article

This study aimed to evaluate the effects of the Martil River rehabilitation project and recently constructed dam infrastructures to reduce flood risks and to promote local socio-economic development on the ecological integrity of the river. The assessment focused on changes in fluvial landforms over time and the evaluation of aquatic ecosystems based on six physicochemical parameters (temperature, pH, electrical conductivity, dissolved oxygen, biochemical oxygen demand, and chemical oxygen demand), morpho-hydrological variables (stream width, water depth, and current speed), habitat indices (QBR, IHF, and MQI), and macroinvertebrate assemblages of EPT, OCH, and Chironomidae (Diptera) at five stations from autumn 2015 to spring 2018 (prior to and during the rehabilitation actions). The results showed that the river rehabilitation project led to profound changes in Martil River’s ecosystem and water quality over time. Physicochemical and habitat measurements at the rehabilitated sites revealed a major change in macroinvertebrate communities due to changes in fluvial landforms in relation to flow-sediment regimes. As a result, some typical species of lentic habitats disappeared, while alien, opportunistic, and lotic species appeared. Full article

With methods for processing remote sensing data becoming widely available, the ability to quantify changes in spatial data and to evaluate the distribution of diverse landforms across target areas in datasets becomes increasingly important. One way to approach this problem is through satellite image processing. In this paper, we primarily focus on the methods of the unsupervised classification of the Landsat OLI/TIRS images covering the region of the Qena governorate in Upper Egypt. The Qena Bend of the Nile River presents a remarkable morphological feature in Upper Egypt, including a dense drainage network of wadi aquifer systems and plateaus largely dissected by numerous valleys of dry rivers. To identify the fluvial structure and stream network of the Wadi Qena region, this study addresses the problem of interpreting the relevant space-borne data using R, with an aim to visualize the land surface structures corresponding to various land cover types. To this effect, high-resolution 2D and 3D topographic and geologic maps were used for the analysis of the geomorphological setting of the Qena region. The information was extracted from the space-borne data for the comparative analysis of the distribution of wadi streams in the Qena Bend area over several years: 2013, 2015, 2016, 2019, 2022, and 2023. Six images were processed using computer vision methods made available by R libraries. The results of the k-means clustering of each scene retrieved from the multi-temporal images covering the Qena Bend of the Nile River were thus compared to visualize changes in landforms caused by the cumulative effects of geomorphological disasters and climate–environmental processes. The proposed method, tied together through the use of R scripts, runs effectively and performs favorably in computer vision tasks aimed at geospatial image processing and the analysis of remote sensing data. Full article

Imaging and measuring the Earth’s relief with sensors mounted upon unmanned aerial vehicles is an increasingly frequently used and promising method of remote sensing. In the context of fluvial geomorphology and its applications, e.g., landform mapping or flood modelling, the reliable representation of the land surface on digital elevation models is crucial. The main objective of the study was to assess and compare the accuracy of state-of-the-art remote sensing technologies in generating DEMs for riverscape characterization and fluvial monitoring applications. In particular, we were interested in DAP and LiDAR techniques comparison, and UAV applicability. We carried out field surveys, i.e., GNSS-RTK measurements, UAV and aircraft flights, on islands and sandbars within a nature reserve on a braided section of the Vistula River downstream from the city of Warsaw, Poland. We then processed the data into DSMs and DTMs based on four sources: ULS (laser scanning from UAV), UAV-DAP (digital aerial photogrammetry), ALS (airborne laser scanning), and satellite Pléiades imagery processed with DAP. The magnitudes of errors are represented by the cross-reference of values generated on DEMs with GNSS-RTK measurements. Results are presented for exposed sediment bars, riverine islands covered by low vegetation and shrubs, or covered by riparian forest. While the average absolute height error of the laser scanning DTMs oscillates around 8–11 cm for most surfaces, photogrammetric DTMs from UAV and satellite data gave errors averaging more than 30 cm. Airborne and UAV LiDAR measurements brought almost the perfect match. We showed that the UAV-based LiDAR sensors prove to be useful for geomorphological mapping, especially for geomorphic analysis of the river channel at a large scale, because they reach similar accuracies to ALS and better than DAP-based image processing. Full article