Geomorphology最新文献

{"title":"Numerical investigation of the refractive properties of near-horizontal rocky shore platforms and their effects on harmonic and stationary wave patterns","authors":"R.L. Krier-Mariani ,&nbsp;W.J. Stephenson ,&nbsp;S. Wakes ,&nbsp;M.E. Dickson","doi":"10.1016/j.geomorph.2024.109491","DOIUrl":"10.1016/j.geomorph.2024.109491","url":null,"abstract":"<div><div>Near-horizontal shore platforms display highly irregular plan shapes, but little is known about the way in which these irregularities influence the significant wave height (<span><math><mover><msub><mi>H</mi><mi>s</mi></msub><mo>̂</mo></mover></math></span>) on the platforms and the frequency components of the nearshore wavefield. As ocean waves share akin refractive properties to light rays, it can be assumed that, similarly to optical lenses, shore platforms can separate waves according to their frequency depending on their geometry. Thus, we use a non-linear Boussinesq wave model to conduct harmonic and bispectral mode decomposition analyses to study the control of concave and convex platform edges over wind waves (WW: 0.125–0.33 Hz), swell waves (SW: 0.05–0.125 Hz) and infragravity (IG: 0.008–0.05 Hz) waves frequencies. For breaking and non-breaking waves, increasing the platform edge concavity intensified wave divergence and subsequent attenuation of SW and IG across the outer platforms, reducing <span><math><mover><msub><mi>H</mi><mi>s</mi></msub><mo>̂</mo></mover></math></span> by up to 25 %. Increasing the platform edge convexity intensified focusing and amplification of SW and WW over the outer platforms, increasing <span><math><mover><msub><mi>H</mi><mi>s</mi></msub><mo>̂</mo></mover></math></span> by up to 18 % and 55 % for breaking and non-breaking waves. In the presence of breaking, IG amplification was affected by wave divergence across the inner platform, a condition determined by a critical convex curvature threshold (<span><math><mfenced><mi>K</mi></mfenced></math></span>=1.8) balancing wave focusing from refraction and defocusing from breaking. We find that convex curvature can determine the relative dominance of WW, SW and IG across platforms. Alongshore, coherent wave interactions governed IG stationary patterns defined by a node near the platform centreline and two antinodes on either side of concave edges. A node was generated at the platform centreline, and two antinodes were observed on either side of the convex edges for <span><math><mfenced><mi>K</mi></mfenced></math></span>&gt;1.8, with the opposite pattern observed for <span><math><mfenced><mi>K</mi></mfenced></math></span>&lt;1.8. Such patterns likely result in alongshore variations in wave-generated currents and erosion shaping rock coasts.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"468 ","pages":"Article 109491"},"PeriodicalIF":3.1,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal vertical accretion in different hydro-geomorphic environments of Indian Sundarban: Assessing the role of mangroves in mitigating sea level rise impacts","authors":"Swapan Paul ,&nbsp;Chandan Surabhi Das ,&nbsp;Subhamita Chaudhuri","doi":"10.1016/j.geomorph.2024.109493","DOIUrl":"10.1016/j.geomorph.2024.109493","url":null,"abstract":"<div><div>The Indian Sundarban, renowned for its unique hydro-geomorphic diversity, faces rising threats from sea level rise, necessitating an examination of the spatio-temporal variation of vertical accretion and the role played by mangroves in mitigating these impacts. As such, fifteen transects were chosen across buffer and transition zones of Indian Sundarban, each equipped with 4–6 sedimentation pins, to gauge accretion rates in premonsoon, monsoon, and postmonsoon season during period March 2020 to March 2022, considering diverse hydro-geomorphic attributes. The vertical accretion rate exhibits a curvilinear pattern, ascending from the lower seafront zone towards the middle of the estuarine region, reaching a peak, and subsequently declining towards the upper estuarine zones. Specifically, in the seafront zone, the yearly mean accretion (focusing solely on accretion and excluding subsidence) ranges between 5 and 10 mm/year, while in the middle estuarine region, it increases to an average of 38.1 ± 9.44 mm/year. However, in the upper zone, the yearly mean accretion decreases slightly to approximately 17.71 ± 9.54 mm/year. Similar patterns are observed when considering the distance from the riverfront to the interior of the mangrove zones. Seasonal analysis demonstrates that the postmonsoon period exhibits the highest accretion, followed by the premonsoon season, while the monsoon tends to be erosional in nature. Mangrove zonation, and subsequent distribution of root height, root diameter, root density, tree density, tree basal area, inundation frequency, current speed, variation in suspended sediment concentration were identified as influential factors affecting vertical accretion rates. Based on multiple regression analysis, root density, inundation frequency, and tree density demonstrated moderate-positive correlations with vertical accretion, whereas distance from the riverfront, root height, and root diameter displayed negative correlations. This study enhances our understanding of the intricate processes behind vertical accretion in the Sundarban, offering valuable insights for future research and advancing discussions on the broader implications of climate change in coastal regions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"467 ","pages":"Article 109493"},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automatic extraction of Transverse Aeolian Ridges (TARs) and analysis of landform influence for the Zhurong landing area on Mars","authors":"Jie Zhang,&nbsp;Sicong Liu,&nbsp;Kecheng Du,&nbsp;Xiaohua Tong,&nbsp;Huan Xie,&nbsp;Yongjiu Feng,&nbsp;Yanmin Jin,&nbsp;Yizhang Lin,&nbsp;Bo Wan","doi":"10.1016/j.geomorph.2024.109489","DOIUrl":"10.1016/j.geomorph.2024.109489","url":null,"abstract":"<div><div>The morphology and surface characteristics of Transverse Aeolian Ridges (TARs) reflect the recent and current environmental evolution of Mars. This study investigates the influence of typical Martian non-aeolian landforms impacted on the distribution and morphology of TARs using multi-source high-resolution orbiter images in the Zhurong rover's landing region at the south of Utopian Plain. This study proposes an automatic and effective approach for extracting TARs, while classifying their types and estimating their geometric parameters, including length, width, height, and angle. The obtained results confirm the effectiveness of the proposed method. In the Zhurong rover's landing region, TARs in flat areas have a sparse distribution and simple morphology. However, TARs are more concentrated and diverse in morphology around typical non-aeolian landforms such as cones and troughs. The orientation of TARs is determined by wind direction, and their width is affected by sediment richness. The morphology and distribution of TARs are also influenced by typical non-aeolian landforms, which modify local wind fields and sediments.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"467 ","pages":"Article 109489"},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling gully erosion susceptibility: A semi-quantitative modeling approach integrated with field data in contrasting landscapes and climate regions","authors":"Mulatu Liyew Berihun ,&nbsp;Atsushi Tsunekawa ,&nbsp;Nigussie Haregeweyn ,&nbsp;Haimanote Kebede Bayabil ,&nbsp;Ayele Almaw Fenta ,&nbsp;Taye Minichil Meshesha ,&nbsp;Samuel Berihun Kassa ,&nbsp;Belay Birhanu Bizuneh ,&nbsp;Yoseph Buta Hailu ,&nbsp;Matthias Vanmaercke","doi":"10.1016/j.geomorph.2024.109485","DOIUrl":"10.1016/j.geomorph.2024.109485","url":null,"abstract":"<div><div>This study addresses the challenge of mapping gully erosion susceptibility, which is often hindered by limited observed data, the complexity of controlling factors, and the uncertainties associated with characterizing these factors. We utilized a semi-quantitative modeling approach that integrates field-based data and ten controlling factors in the Chemoga watershed of Ethiopia's Upper Blue Nile basin. The resulting gully erosion susceptibility map was compared with a random forest-based approach to assess the methodological applicability. Additionally, an independent dataset from adjacent watersheds was used to validate the approach. The findings revealed that certain landscape positions with specific elevation ranges and slope steepness were more susceptible to gully erosion due to factors such as rainfall, lithological formations, soil characteristics, and agricultural activities. Approximately 10 % of the watershed area was affected by gully erosion, with varying susceptibility levels. The comparison between the semi-quantitative and random forest approaches demonstrates a total agreement of around 58 %, with minimal differences in susceptibility classes. The study also highlights a strong agreement between simulated and observed susceptibility maps, with a 76 % PBIAS (Percent Bias) value for the simulation and a lower 48 % agreement for the random forest approach. Furthermore, in the adjacent watershed, 65 % of the area exhibits no discrepancies between observed and simulated maps. This suggests that the semi-quantitative approach is effective in extrapolating gully erosion susceptibility when detailed data is limited, offering a cost-effective and efficient solution. The study emphasizes the utility of the semi-quantitative modeling approach in mapping gully erosion susceptibility and its potential for practical applications in land management and intervention strategies.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"468 ","pages":"Article 109485"},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meteorological factors control debris slides and debris flows in a high-Arctic glacier basin (Ny-Ålesund, Svalbard)","authors":"Erik Kuschel ,&nbsp;Florian Tolle ,&nbsp;Vinzent Klaus ,&nbsp;Ursula Laa ,&nbsp;Alexander Prokop ,&nbsp;Jean-Michel Friedt ,&nbsp;Eric Bernard ,&nbsp;Christian Zangerl","doi":"10.1016/j.geomorph.2024.109492","DOIUrl":"10.1016/j.geomorph.2024.109492","url":null,"abstract":"<div><div>Landslide processes are one of the dominant agents of erosion and sediment transport on sediment-mantled slopes in arctic environments. Increased landslide activity is anticipated as climate change is projected to decrease mountain slope stability. High-Arctic environments, such as Svalbard, serve as crucial observatories for investigating current and future slope dynamics within a changing climate, particularly due to arctic amplification effects. Despite the significance of Arctic regions, empirical evidence in high latitudes is often lacking. This scarcity can be attributed to the absence of long-term, high-resolution terrain data with sufficient temporal resolution to assess the impact of meteorological boundary conditions on landscapes altered by climate change. However, addressing this gap in empirical evidence is essential for understanding the complex interplay between meteorological variables and debris slide and debris flow evolution in Arctic environments. This study presents a unique high-resolution remote sensing dataset within a high-Arctic glacier basin acquired over a 10-year period. Through the combination of terrestrial laser-scanning and an autonomous camera network, we were able to investigate the impact of meteorological boundary conditions on the trigger mechanisms of translational debris slides and debris flows and unravel paraglacial slope evolution following recent glacier retreat on the example of the Austre Lovénbreen glacier basin (Svalbard, Norway). Translational debris slides accounted for approximately 96 % (<em>N</em> = 147) of the total sediment flux observed, with debris flows (<em>N</em> = 21) acting as a secondary agent of sediment transport. The debris slide activity significantly increased between 2011 and 2021. Heavy rainfall events primarily influence the frequency and magnitude of debris slides during the hydrological summer, while the duration and intensity of the thawing period serve as the principal control for their initiation. Furthermore, a 2-year recurrence period for major debris flows (≥ 400 m³) was found, which is about 2.5 to 5 times shorter than previous estimates for the last few decades on Svalbard. In conclusion, this study highlights the impact of meteorological factors on debris slide frequency and magnitude within high-Arctic glacier basins, shedding light on the dynamics of paraglacial slope modification in Arctic environments affected by climate change.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"467 ","pages":"Article 109492"},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controls on coastal bluff erosion of a drowned drumlin field: Boston Harbor, Massachusetts","authors":"Sarah K. Black,&nbsp;Zoe J. Hughes,&nbsp;Duncan M. FitzGerald","doi":"10.1016/j.geomorph.2024.109490","DOIUrl":"10.1016/j.geomorph.2024.109490","url":null,"abstract":"<div><div>Eroding coastal bluffs pose significant risks to coastal communities, and an improved understanding of their erosional processes and mechanisms is essential for developing effective management strategies. The Boston Harbor Islands comprise more than two dozen drowned drumlins that were formed during the late-Pleistocene, many of which are now connected by spits. Exposed bluffs on the islands experience erosion due to waves and precipitation and are increasingly threatened by accelerating sea-level rise (SLR). Retreat rates for 31 bluffs along the drumlin shore, derived from orthoimagery (1995–2021) using the Digital Shoreline Analysis System add-in for ArcMap 10.8, range from 0.0 m/yr to 1.5 m/yr. These rates were examined in relation to several factors, including shoreline orientation, significant wave height during extratropical storms, till matrix composition, base elevation, bluff height, and presence of engineering structures. Clusters of bluffs with similar characteristics were identified, suggesting that high retreat rates coincide with bluffs that experience high wave energy, face the northeast and have high sand-to-mud ratios. The complexity of the Boston Harbor drumlin field and the variability of individual factors controlling erosion highlights the impracticality of developing a universal statistical model for predicting erosion rates. Rather a more suitable approach involves assessing trends among clusters of bluffs with similar characteristics. A similar approach can be taken for exploring the variability in retreat rates along other coastlines with complex or irregular bluff systems and wave fields.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"468 ","pages":"Article 109490"},"PeriodicalIF":3.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The timing of large drainage rearrangement in South America: A study based on morphological and ecological evidence","authors":"Fernanda Apericida da Silva Cassemiro PhD ,&nbsp;André Augusto Rodrigues Salgado PhD (Professor) ,&nbsp;Rodrigo Wagner Paixão PhD ,&nbsp;Éric Andrade Rezende PhD","doi":"10.1016/j.geomorph.2024.109457","DOIUrl":"10.1016/j.geomorph.2024.109457","url":null,"abstract":"<div><div>This study aims to characterize and determine the timing of a major drainage rearrangement between two vast river basins, each exceeding 600,000 km²: the Paraná and São Francisco basins in South America. We used geomorphological analyses and the computational Black Top Hat (BTH) method to identify river captures. By using freshwater fish distribution and evolution data, we performer biogeographical analyses to assess the fish dispersal patterns. Our results show that in the past the upper Paraná River (known locally as the Grande River) once flowed into what is now the São Francisco River Basin. Biogeographical analysis corroborates this past connection between Grande and São Fracisco rivers This analysis reveals also that between 6 and 5 and 2 million years ago, a significant drainage rearrangement occurred, when the Paraná River Basin captured the Grande River and its tributary (the Sapucaí River). In this process the São Francisco Basin losing 50,000 km² of its area to the Paraná River Basin.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"468 ","pages":"Article 109457"},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk assessment of a glacial lake with abruptly slowing expansion, Jiongpu, Southeastern Tibet","authors":"Taixin Peng ,&nbsp;Ningsheng Chen ,&nbsp;Shiva P. Pudasaini ,&nbsp;Martin Mergili ,&nbsp;Tao Wang ,&nbsp;Mei Liu ,&nbsp;Donghui Shangguan","doi":"10.1016/j.geomorph.2024.109471","DOIUrl":"10.1016/j.geomorph.2024.109471","url":null,"abstract":"<div><div>The expansion of potentially hazardous glacial lakes is a symptom of global warming during this interglacial period. A pertinent example is the Jiongpu glacial lake in southeastern Tibet, the area of which has expanded approximately fivefold in the last half-century. However, recently, the glacier tongue has retreated to a high steep slope, and the rate of retreat of the glacier and expansion of the lake have temporarily slowed. The risk of a glacier tongue landslide after glacier detachment and subsequent glacial lake outburst flood (GLOF) needs to be assessed. In this study, we employed a combination of unmanned aerial vehicle (UAV), sonar, geological radar, remote sensing, field investigation, sampling, drilling, and dating techniques to determine the critical parameters of potential GLOFs, including glacier tongue geometry, lake bathymetry, and moraine dam geometry and composition. Utilizing empirical models and multiphase flow models, we identified the most hazardous triggers and simulated the processes of a glacier tongue landslide into the lake, moraine dam overtopping by a displacement wave, and subsequent flood evolution. The results showed that the most hazardous trigger in volume is a glacier tongue landslide, accounting for 58.29 % of all triggers associated with potential GLOFs. Lapped by the largest glacier tongue landslide impulse wave, the moraine dam would not fail because the minimum safety factor is approximately 1.66 ± 0.7 according to empirical methods and geological slope simulation. However, overtopping would occur, resulting in a peak discharge of approximately 9740 ± 4137 m³/s at the moraine dam based on r.avaflow calculations. The flood would reach the densely populated Jinling township and inundate approximately 46 ± 4.55 % of the houses according to HEC-RAS. Reducing the water level of the glacial lake represents an effective strategy for mitigating potential losses. This concise, physics-based method effectively assesses GLOF triggers and processes and can be applied to risk assessments of other expanding glacial lakes.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"468 ","pages":"Article 109471"},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scale-dependent interactions in coastal biogeomorphic landscapes: Pioneer both inhibits and facilitates primary foredune builder across spatial scales","authors":"Carlijn Lammers ,&nbsp;Valérie C. Reijers ,&nbsp;Tjisse van der Heide","doi":"10.1016/j.geomorph.2024.109486","DOIUrl":"10.1016/j.geomorph.2024.109486","url":null,"abstract":"<div><div>Ecosystem engineers often drive landscape formation and vegetation succession by modifying environmental conditions. Along the Northwestern European coast, dune formation is classically believed to be pioneered by sand couch (<em>Elytrigia juncea</em>), followed by the primary foredune builder marram grass (<em>Calamagrostis arenaria</em>, formerly <em>Ammophila arenaria</em>) once sufficiently large dunes have formed. However, these ideas lack experimental validation, leaving the specific relationship between sand couch, the landscape they form, and marram grass establishment unknown. Here, we experimentally investigated this relationship by planting 975 young marram grass plants in two sand couch dominated, embryonic dune systems. Using structural equation models, we examined the effect of sand couch and the landscape attributes (i.e., elevation, distance to sea and elevation change) on marram grass establishment. Results reveal indirect local inhibition by sand couch via landscape modifications on survival of establishing marram grass. Specifically, sand couch elevated the environment. In turn, elevated areas eroded (i.e., changed in elevation) more in winter, which was the key factor reducing marram grass survival. At the landscape scale, however, we observed the highest survival in relatively stable and sheltered microsites formed because of sand couch induced dune building. While the indirect local inhibition by sand couch for marram grass survival was found at both locations, the direct effect of sand couch on marram grass survival and shoot formation were location and thus context dependent. For marram grass survival, the relation with sand couch was neutral in exposed and positive in sheltered conditions and for shoot formation it was negative in exposed and neutral in sheltered conditions. Similar to scale-dependent interactions found in other biogeomorphic landscapes (e.g., salt marshes, seagrass, mussel beds), we suggest that interspecific facilitation acts on larger spatial scales rather than the commonly suggested small-scale facilitation through created elevation. More specifically, we suggest that dune formation by pioneer species leads to the creation of stable and sheltered microsites beneficial for establishment of later successional species at the landscape-scale.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"467 ","pages":"Article 109486"},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphometric characteristics of glacial cirques and former glaciers in the Geyik Mountains, Western Taurus, Türkiye","authors":"Zeynel Çılğın ,&nbsp;Ian S. Evans ,&nbsp;Ferhat Keserci ,&nbsp;Ergin Canpolat ,&nbsp;Cihan Bayrakdar","doi":"10.1016/j.geomorph.2024.109474","DOIUrl":"10.1016/j.geomorph.2024.109474","url":null,"abstract":"<div><div>Using the Glacier reconstruction (GlaRe) toolbox, reconstructions of former glaciers in the Geyik Mountains, part of the Taurus Mountain system in southern Türkiye, show that an area of 132.5 km² was glaciated in the last major glaciation, which left clear terminal and hummocky moraines. Glaciers were 1.4 to 12 km long and those from 49 cirques merged to form a broad 75 km² piedmont glacier in the Namaras Valley, up to 400 m thick. A thorough analysis of morphometry of the 98 Geyik cirques, using the revised Automated Cirque Metric Extraction version 2 (ACME2) toolbox, shows that they are relatively small, with limited widths: the median length/width ratio of 1.29 is unusually high. With size, length and width increase faster than depth, demonstrating strong static allometry. Maximum slope averages 59°, minimum 3.3° and axial 25°. A combination of low hypsometric integral, high axial profile closure and high axial height-length integral is proposed as a measure of cirque development.</div><div>The main summits are on sharp ridges on cirque crests, showing that they have been lowered by glacial erosion (by cirque development). Glaciation was strongly asymmetric, with cirque vector mean aspect between northeast and north-northeast. This shows the dominance of solar radiation effects, with some modification from westerly winds. Glacier palaeo- Equilibrium Line Altitudes (pELAs) rise northeastwards and cirque floor minimum altitudes (CFAs) rise toward east-northeast, both showing the importance of moist air from the Mediterranean, 38–55 km to the southwest. pELA averages 2208 m above sea level (a.s.l.) (2277 m area-weighted); CFA averages 2234 m. CFA varies mainly with summit altitudes; where related palaeoglaciers are short CFA is somewhat below pELA, but for longer ones it is above. The most likely palaeoclimate to form these glaciers involves a precipitation increase of 53–72 % with a temperature fall of 8 °C compared with present-day. The cirques formed under similar or less severe conditions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"467 ","pages":"Article 109474"},"PeriodicalIF":3.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}