Geomorphology最新文献

{"title":"Monsoon control on evolution of the western Indian aeolian landscape: Insights from U-Pb detrital zircon geochronology and Sr-Nd-Hf isotope studies of the Thar Desert sand dunes","authors":"","doi":"10.1016/j.geomorph.2024.109429","DOIUrl":"10.1016/j.geomorph.2024.109429","url":null,"abstract":"<div><p>Evolution of landscape is linked to the interplay of tectonics, lithology, and climate. To better understand the evolution of aeolian landscape of the western Indian subcontinent and its major driver/s, we carried out a quantitative provenance analysis of the sand dunes of Thar Desert and desert river Luni using whole rock Sr-Nd-Hf isotopes and detrital zircon U-Pb geochronology. Our findings show Himalayan origin for the Thar sands. River Indus consistently contributed about 30–40 % of the total dune sand across the desert. The sand dunes in the north and the west of the desert are dominated by sediments derived from the source rocks drained by Sutlej river and its tributary Beas river whereas the dunes of central Thar are dominated by sediments supplied by rocks drained by Jhelum, Ravi and Chenab rivers. Analysis of detrital zircon U-Pb age spectra of sediments from desert river Luni reveal that dune sand of southern Thar Desert forms nearly 80 % of its present-day sediment load. Notably, the Thar dune sands show remarkable compositional similarity to the early to middle Holocene Indus delta sediments suggesting shared source/s. Existing paleolimnological and climatic records suggest a wetter environment in the Thar during early to middle Holocene. This evidence coupled with compositional similarities between the Thar dunes and the Indus delta sediments from the same period, indicate a probable extension of the Indus-Sutlej floodplain into southeast Thar during that time. Subsequent aridification of the region in the late Holocene likely led to seasonal winds recycling this fluvial sand to form the present-day Thar dunes, and shaping the current aeolian landscape in western India.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243724","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":"A model-based characterization of confined meandering rivers","authors":"","doi":"10.1016/j.geomorph.2024.109427","DOIUrl":"10.1016/j.geomorph.2024.109427","url":null,"abstract":"<div><p>In this paper we analyze the dynamics of meandering rivers that flow in geologically confined floodplains. We use a state of art meander morphodynamic model in which the floodplain erodibility can be spatially variable, and can thus be highly reduced where nearly unerodible lateral walls are simulated. We propose a hybrid empirical and model-based indicator to estimate the degree of confinement relative to the potential, unconfined meander belt. Together with commonly used meander morphometric indicators, we propose two novel planform metrics to represent the observed tendency of confined meanders (i) to develop long reaches attached to the geological boundaries, and (ii) to develop more frequent crossing of the floodplain central axis. Results reproduce realistic planforms of confined meanders, quantitatively support previously suggested qualitative classifications of confined meandering rivers, and provide a rational framework to compare meandering rivers having different degree of confinement (strong, moderate, unconfined), as well as different hydro-morphological conditions. Good agreement between model predictions and the few existing field observations support the proposed approach.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243723","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":"Shore ice control on coastal geomorphic evolution in cold regions","authors":"","doi":"10.1016/j.geomorph.2024.109409","DOIUrl":"10.1016/j.geomorph.2024.109409","url":null,"abstract":"<div><p>Shore ice is a common feature on cold climate coasts, which are abundant in mid- and high-latitude regions, however it is understudied. Previous research has reported both beach protection and erosion as potential impacts from shore ice presence. Altered ice dynamics resulting from a changing climate are likely to intensify these impacts. To address this discrepancy and improve future coastal change predictions we conducted the first combined field, laboratory and modeling study of shore-ice processes and impacts. Beach and nearshore morphology mapping, experiments with a novel cryogenic wave tank, and 3D coastal evolution modeling revealed that shore ice protected the beach from storms, but scoured the nearshore at the ice edge and transported sediment offshore, likely past the depth of closure. This resulted in enhanced beach erosion during the ice-free and non-storm season, countering the protective benefit from the ice. This study indicates that shore ice plays an important and likely evolving role in geomorphic evolution along cold climate coasts.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172749","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":"Multi-millennia surface dynamics: Novel investigation approach unveils climate relation to mountain erosion (Serra da Estrela, Portugal)","authors":"","doi":"10.1016/j.geomorph.2024.109416","DOIUrl":"10.1016/j.geomorph.2024.109416","url":null,"abstract":"<div><p>Multi-millennia data logs on surface denudation variation in alpine landscapes are scarce, yet they are needed to understand the impacts of environmental changes on denudation. On the example of the Serra da Estrela plateau in Portugal, we explored a new archive, vertical bedrock outcrops (tors), and the capability of the Tor Exhumation/Exposure Approach (TEA) to capture surface denudation variations even in formerly glaciated landscapes. Therefore, we used vertical in-situ ¹⁰Be to date surface exposure of tor slopes in formerly glaciated and non-glaciated parts of the plateau during the last glacial period.</p><p>Based on the surface exposure ages, surface denudation variations covering the last ∼200 ka could be derived that revealed glacial retreat dynamics in greater detail. Higher isotope contents and, thus, surface exposure ages were found in the non-glaciated area. At the formerly glaciated sites, the ice margin retreat is reflected in the isotope signature of the tors. The younger rock surfaces had a higher chemical weathering degree than older surfaces at the non-glaciated site as a result of a higher water availability. Highest-elevation tors have experienced (subglacial/hydrothermal) chemical weathering, mass wasting and stripping (∼6 ± 0.5 ka) during the transition from a cool moist, to an oceanic-Mediterranean climate.</p><p>Yet, tors in the non-glaciated area yielded lower surface denudation rates with a maximum of 0.53 [mm yr⁻¹] compared to the glaciated area (reaching values of up to 18.29 [mm yr⁻¹]). Since the LGM and the concomitant increase in air temperature, surface denudation also distinctly changed. Temperature trends and surface denudation developed analogously for the last ∼150 ka. Vegetation change or human activity's impact on surface denudation cannot be discerned due to the too low chronological resolution. Overall, we demonstrated that multi-millennia tor records of variation in surface denudation can be obtained using the TEA, even in formerly glaciated areas. Thus, this study contributes to revealing the sensitivity of mountain erosion rates to past environmental changes.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172748","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":"Non-uniform dune development in the presence of standalone beach buildings","authors":"","doi":"10.1016/j.geomorph.2024.109402","DOIUrl":"10.1016/j.geomorph.2024.109402","url":null,"abstract":"<div><p>Shoreward sand transport and dune development are increasingly influenced by the urbanization of beach-dune systems in the Netherlands. Three topographic datasets, on various spatio-temporal scales, are used to study the effect of standalone buildings on long term local dune development. On the smallest scale, terrestrial laser scans are used to study the geomorphological effects of two sea containers on the beach. On the intermediate scale, the geomorphological effects of a beach pavilion on the local dune development are studied with a 2-year topographic dataset of (bi) monthly permanent laser scans. Finally, 15 yearly airborne lidar scans of the beach-dune system in Noordwijk are used to evaluate the effect of multiple beach pavilions on dune growth variations. The small-scale experiment shows that horseshoe-shaped deposition patterns developed on the leeside of the containers. These depositions follow daily wind changes and leave deposits corresponding to the residual wind direction over the whole measuring period. Similar patterns are found around the larger beach pavilion, but anthropogenic activities like bulldozing and beach shaping make the determination of the effect on dune development harder to discern. Evaluation of the longer-term dataset reveals large variations in dune height and volume around beach pavilions. Dune height/volume increases vary between 1 and 8 m in height and 0–200 m3 in volume. A variability analysis shows that the length scale of alongshore variability in dune height/volume of urbanized dunes can be 10 times smaller than for natural dunes. For about half the beach pavilions, variations in dune height and volume are significantly correlated to the location of beach pavilions but correlation to particular beach pavilion properties is yet inconclusive.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169055","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":"Travertine and calcareous tufa occurrences as an indicator of the ongoing tectonic activity of the Central Slovak Fault System inferred from airborne laser scanning data, geomorphometric, and structural analysis (Northern Slovakia)","authors":"","doi":"10.1016/j.geomorph.2024.109420","DOIUrl":"10.1016/j.geomorph.2024.109420","url":null,"abstract":"<div><p>The travertine formation process, active over the Quaternary, has enabled the origin of one of the largest travertine accumulations in the Western Carpathians. Travertines and calcareous tufas are associated with the tectonic activity of the Central Slovak Fault System, a 45 km wide and 140 km long N-S oriented fault zone. As the geological mapping, structural analysis, geomorphometric and isobase surface analysis revealed, the development of faults was polyphase and the travertine/tufa precipitation was not a continuous process. In addition, numerous travertine/tufa morphofacial varieties have been recognized within the study area, such as travertine/tufa terraces and tufa cascades, hillslope paludal tufa crust, phytoherm framework tufa barrages, lacustrine microdetrital tufas, bryophyte-dominated self-built channel, and fluvial tufa crust, reflecting its local geomorphology and precipitation factors. In the Revúcka dolina Valley, the travertine/tufa geobodies thus represent a reliable indicator of the tectonic activity over the Neogene up to Quaternary. The structural data provided relevant evidence confirming the character of orogen-parallel extension for the current tectonic/neotectonic regime in the Inner Western Carpathians. High-resolution topography derived from airborne laser scanning and the subsequent application of various geomorphometry techniques allowed quick identification of the edges of the terrace cascade systems and morpholineaments. Based on our observations, in this zone, the significant vertical movements of normal faults took place with a maximum estimated offset of 800–1000 m. The achieved results also support the use of the presented multifaceted methodology to understand the interplay between geomorphogenesis, hydrology, and tectonics.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163032","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":"Outburst flood events since the Last Glacial Maximum in the Hutiao Gorge of Jinsha River: Geomorphological evidence from eddy gravel bars","authors":"","doi":"10.1016/j.geomorph.2024.109415","DOIUrl":"10.1016/j.geomorph.2024.109415","url":null,"abstract":"<div><p>Breaching of natural dams in the Hutiao Gorge of the Jinsha River across the Yulong-Haba Mountains is one of the major geomorphological events in the largest river of Asia. Catastrophic flood events have an important influence on the geomorphological evolution of the First Bend of the Yangtze River since the Last Glacial Maximum (LGM). However, detailed geomorphological evidence, ages, and depositional phases of outburst flooding remain unclear. In this paper, large-scale gravel bars overlying the river terraces and dammed lakes are analyzed within the Daju Basin. The macroscopic geomorphological characteristics of megaflood landforms with large thickness and uniform gravel bars are similar to those of Missoula and Altai megafloods. Morphological analysis shows that eddy gravel bars (EGBs) with rhythmic structure are characterized by a dome-shaped protrusion in the cross section and a gravel mound in the longitudinal section. Each bar with oblique, parallel and massive bedding was analyzed from the horizontal and vertical directions. Three dome-shaped bars clearly show at least three palaeoflood phases. Quartz grain surface macrotextures are mainly V-shaped pits and conchoidal fractures, which exhibits a high-energy environment during the flood. The stratigraphic sequence model of EGBs is dominated by coarse sand and fine gravel rhythmic bedding in high-energy eddy environments and suspended sand deposits in low-energy backwater environments. Such phenomenon reveals megaflood fluctuates, which is also confirmed by geochemical difference. The episode of natural dam break floods triggered by tectonic activity and glacier fluctuation was dated to 20–17 ka during the LGM. Sedimentary pattern of EGBs offers fresh insights into understanding the megaflood geomorphological characteristics of the upper Yangtze River and better identification similar high-energy palaeoflood landforms in the southeast Tibetan Plateau.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151193","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":"Catchment-scale network analysis of functional sediment connectivity during an extreme rainfall event in the Grastal catchment, Austrian Central Alps","authors":"","doi":"10.1016/j.geomorph.2024.109419","DOIUrl":"10.1016/j.geomorph.2024.109419","url":null,"abstract":"<div><p>Global warming significantly impacts sediment dynamics in glaciated catchments, affecting water resource operations, water quality, recreational activities, and ecological systems. The propagation of climate-change-induced geomorphic changes and the catchment's sediment yield are moderated by sediment connectivity, defined as the degree to which a geomorphic system facilitates sediment transfer. Quantifying functional sediment connectivity at the catchment scale remains a challenge. To address this, we propose a novel approach combining graph theory with the morphological method. This approach is exemplified through a detailed case study of a 2022 thunderstorm event in the Grastal valley, Tyrol, Austria. First, a graph of potential sediment cascades is constructed using a geomorphological map, a digital elevation model and a flow routing algorithm. A short-term Digital Elevation Model of Difference (DoD) from consecutive ALS surveys is then used to infer sediment fluxes and calculate the Sediment Delivery Ratio (SDR) for each landform. The primary sediment mobilising processes were debris flows and fluvial erosion, with a significant proportion of debris flow material being deposited on slopes, not reaching the fluvial corridor. Strong fluvial erosion was observed in the proglacial area, but the propagation of these geomorphic changes is halted by an alluvial fan and a lake. Most landforms can be clearly categorised as connecting or disconnecting features based on their SDR. In total, a maximum of 12 % of mobilised sediments exited the catchment. Our findings demonstrate that (i) short-term, catchment-wide DoDs are valuable for assessing functional connectivity at an event temporal scale, (ii) using landforms as fundamental spatial units allows for the identification and in-depth analysis of critical sediment sinks and sources, and (iii) graph analysis facilitates the catchment-wide calculation of sediment delivery ratios between meaningful fundamental units and the delineation of significant sediment cascades.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169555X24003696/pdfft?md5=c14a9eba1d3b06b8a5f9cc3a7322ecc2&pid=1-s2.0-S0169555X24003696-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142150958","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":"Diverse fluvial aggradation and incision response to interglacial—Glacial transitions in the headwaters of the Yangtze River, SE Tibetan Plateau","authors":"","doi":"10.1016/j.geomorph.2024.109418","DOIUrl":"10.1016/j.geomorph.2024.109418","url":null,"abstract":"<div><p>As a key geomorphic archive, staircase sequences of terraces and sediments record the history of fluvial aggradation and incision, which are related to tectonic activities, climatic fluctuations, and varying base levels. While numerous studies have investigated their influence on the formation of fluvial terraces, the manner in which rivers adapt to diverse climatic transitions (specifically, the shifts from warm to cold and from cold to warm) remains a subject of ongoing debate, particularly when considered within varying tectonic and climatic contexts. Here, we address this issue by reconstructing terrace distributions and identifying sedimentary features with OSL dating in the headwaters of the Yangtze River in the southeastern Tibetan Plateau. We discovered two distinct sets of thick valley-filling sequences at different elevations indicating two phases of aggradation during the penultimate and last glacial periods, when the Yangtze River was in a transport-limited condition. During the warmer interglacial and deglacial periods, increased monsoon precipitation led to higher discharge, causing the river to incise into these valley fills. In addition, superimposed tectonic activities produced diverse river response to the climatic transition from interglacial to glacial between the upstream shallow valley and the downstream deeply incised gorge. In the upper valley, stable tectonic conditions resulted in minimal incision, with younger deposits overlying older ones. Conversely, in the downstream gorge, with more intense tectonic activities, sediments only partially covered the riverbed. These sediments acted as abrasion tools, facilitating rapid incision during the warm-to-cold transition, thereby creating two separated valley fills. This finding enhances our understanding of how tectonic forces influence river responses to interglacial—glacial cycles.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151192","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":"Dune Pattern interrupted by ephemeral drainages and human activities, on the northern Ordos Plateau in China","authors":"","doi":"10.1016/j.geomorph.2024.109413","DOIUrl":"10.1016/j.geomorph.2024.109413","url":null,"abstract":"<div><p>Dune patterns are considered a representation of the desert landscape, and their formation and evolution are affected by climatic conditions and regional differences in the sedimentary environment. High-resolution satellite images from 2007 to 2021 were used to quantitatively analyze the spatiotemporal variation of pattern parameters on the northern Ordos Plateau in China by using the dune pattern analysis method. Combined with meteorological factors and land use changes, this analysis provides insight into the dynamic change of dune patterns and the main controlling factors of dunes evolution. The results show that ephemeral drainages and roads developed in the plateau interrupt dune agglomeration downwind without significant changes in the pattern parameters from west to east and without obvious spatial variation trend of parameters in each area separated by linear obstacles. In the past 14 years, the crestlines of the sampled dunes have always been NE-SW and NNE-SSW, with a counterclockwise deflection that gradually occurred with time. The crestline length and dune height showed a decreasing trend, while the dune spacing and defect density showed an increasing trend. After 2012, a significant rise in precipitation and a drop in wind speed contributed to vegetation recovery, promoting the transformation of barchan dunes to parabolic dunes and breaking the original self-organization evolution of dunes. Therefore, the spatiotemporal evolution of dune pattern in the northern Ordos plateau is driven by natural and human factors and differs from that in the hinterland of mobile deserts.</p></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163033","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}