Geomorphology最新文献

Numerical study on morphology and material spatial distribution of landslide dams in different shaped valleys

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-18 DOI: 10.1016/j.geomorph.2025.109727

Yuanyuan Zhou , Zhenming Shi , Hongchao Zheng , Chengzhi Xia

The characteristics of a landslide dam, including morphology and material spatial distribution, are dependent on its formation conditions and directly affect the dam stability. In this study, a series of numerical modeling tests were performed to reveal the importance of six accessible factors (landslide material, volume, height, slope gradient, width of sliding path, and valley shape) on dam characteristics. Two deposition modes were observed during dam formation: “collisional spreading” mode in U-shaped valleys and “pushing and climbing” mode in V-shaped valleys. The dam height was strongly related to the valley shape and landslide volume, whilst the dam width was highly sensitive to the slope gradient and width of sliding path. The crest surface frontal angle and up/downstream slopes were mainly influenced by slope gradient and landslide material. Due to the different deposition modes, the main factors regulating the material distribution of the dam in the U-shaped valley were the width-to-depth ratio of the valley and landslide height, while in the V-shaped valley, the slope gradient and valley bank slope were the primary parameters. The prediction models considering significant influencing factors were established for evaluating the geometrical and material distribution parameters of a landslide dam. Two case studies (Attabad and Baige landslide dams) are presented to test the prediction models. This study provides a rapid prediction of landslide dam characteristics, which can be used to assess the dam stability.

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引用次数: 0

Seismic response and run-out process of the Shiguchuan landslide: Insights from geological investigations and numerical simulation

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-14 DOI: 10.1016/j.geomorph.2025.109725

Ping Sun , Haojie Wang , Chaoying Ke , Kangyun Sang , Shuai Han , Shuai Zhang

Tianshui City is located in the transitional zone between the Western Qinling Mountains and the Loess Plateau, an area significantly affected by strong earthquakes. Historical seismic events have induced numerous landslides in this region. Through an integrated methodology combining field investigations, drilling, and numerical simulation, the seismic response and failure mechanisms of the loess-bedrock slope are revealed, and the run-out process of Shiguchuan landslide under basic and rare seismic conditions is examined. The key findings are as follows: The seismic response of the loess-bedrock slope is primarily controlled by the thickness of the loess layer, topographic features, and the loess-bedrock interface, which exhibits significant elevation amplification, surface amplification, and loess layer amplification effects. Below the mid-slope elevation, horizontal acceleration amplification factors (AAFs) dominate over vertical components, whereas this relationship reverses above the mid-slope elevation. Spectral analysis reveals that the seismic amplification in loess-bedrock slopes exhibits pronounced frequency-dependent characteristics. Significant amplification of horizontal components (2.2–2.5 Hz) and vertical components (5–6 Hz) is observed in the upper-middle slope section. The failure mechanism of the Shiguchuan landslide is characterized by high-level shear sliding of the mid-upper slope loess along the bedrock interface. Under rare seismic conditions, the run-out and accumulation behaviors of the landslide, as determined by numerical simulations, are generally consistent with the post-failure characteristics observed through field investigations, suggesting that the Shiguchuan landslide was likely triggered by seismic ground motions with a PGA (peak ground motion acceleration) of ≥0.6 g. These results have significant implications for understanding the dynamic behavior of such landslides and the potential triggering seismic intensities.

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引用次数: 0

Comment to “Geomorphology of subaerial mud volcanoes in Azerbaijan: Issues about edifice construction and degradation”. Insights from 10Be dates for the Ayazakhtarma mud volcano

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-12 DOI: 10.1016/j.geomorph.2025.109710

Vincent Regard , Francis Odonne , Patrice Imbert , Sébastien Carretier , Sandrine Choy

In their article, Komatsu and Feyzullayev (2024) present a typology of mud volcanoes in Azebaijan, and discuss the temporal evolution of these volcanoes on a scale of a few years. We are adding new quantitative data, consisting in cosmonuclide ¹⁰Be data on Ayazakhtarma mud volcano (48.98°E, 40.37°N). Such analyses show the evolution of the volcano on the scale of 100 years and reveal two important points. (i) The central part of the volcano is built via significant vertical mobility, which leads to a homogeneous cosmogenic signal. (ii) The medial/external parts record the enlargement of the edifice, which takes at least 800 years. This age could correspond to the last major eruption or a continuous expansion at a maximum growing rate of 87 cm/yr.

引用次数: 0

Dynamic friction behaviors of slip surfaces in granite and implications for large rapid rockslides with long runouts on the southeastern Tibetan Plateau: Constraints from an experimental investigation

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-07 DOI: 10.1016/j.geomorph.2025.109712

Baoping Wen, Lichun Guan, Lian Zhang

Large rapid rockslides with long runouts are the most destructive type of landslide in nature. The dynamic friction behavior of the slip surface of this type of landslide controls its initial acceleration during motion in the source section. To explore the dynamic friction behaviors of the slip surfaces in granite rockslides, a series of high-velocity friction experiments were conducted on simulated slip surfaces in granite. The samples were collected from two rockslides on the southeastern Tibetan Plateau. The experimental results revealed that the dynamic friction behaviors of the slip surfaces were slip-weakening, i.e., decreases in their dynamic friction coefficients with increasing displacement, at velocities ≧0.01 m/s. The pattern of the slip-weakening was single-stage weakening at velocities <0.1 m/s, and multi-stage weakening at velocities ≧0.1 m/s. The weakening was velocity-dependent when gouge was produced at velocities ≤0.1 m/s, and complex slip-weakening once partial melting occurred at velocities ≥0.5 m/s. The dynamic friction behaviors of the slip surfaces had no certain correlation with the normal stress at velocities ≧0.01 m/s. Variable dynamic friction behaviors of slip surfaces in granites clarify that the application of the Coulomb friction model to rapid rockslides is questionable, and that the volume-dependent effect of their friction coefficients in the source sections is uncertain. The dynamic friction behaviors of the slip surfaces in the granites from the two rockslides in this study imply that extreme reductions in their slip surfaces' friction coefficients could have occurred in the source sections and led to significant initial accelerations before entering the transition sections. Their slip-weakening was likely velocity-dependent at a velocity range from 0.1 to 0.1 m/s.

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引用次数: 0

Characterizing spatial patterns and regionalization of anthropogenic landforms using multi-source geospatial data: Insights from Loess Plateau of China

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-07 DOI: 10.1016/j.geomorph.2025.109708

Yang Chen, Xin Yang, Huangjunxi Fu, Chenrui Li, Guoan Tang

Anthropogenic forces have become a significant factor in the development of geomorphology, influencing landform morphology and usage in diverse ways across natural and societal environments. Despite their growing impact, few studies have quantified the morphology and distribution of anthropogenic landforms at large scales to reveal the spatial patterns of human modification on the surface. To address them, we propose a framework that includes three classical anthropogenic landforms, i.e., terraces, check dams, and impervious surfaces, on the Chinese Loess Plateau (CLP) to measure the morphology differences at the basin level. Using 10-meter resolution geospatial datasets, we conducted a quantitative analysis of spatial patterns across four landscape dimensions. We developed a scoring system based on the entropy-weight method to measure the intensity of anthropogenic landforms. Additionally, a data-driven clustering algorithm incorporating spatial dependence was applied to regionalize anthropogenic landforms. Our findings reveal significant spatial variations in the distribution of anthropogenic landforms. The east-central and west-central areas of the Loess Plateau exhibit clear signs of human modification, with high-intensity anthropogenic landforms concentrated near densely populated areas. The clustering effect of these landforms is particularly prominent in the central-eastern zones of the CLP due to the population and many soil and water conservation measures. By regionalizing anthropogenic landforms into eight distinct regions, each characterized by unique morphological features. Four regions are dominated by terraces; two regions are settlement-dominated and the others are mixed. Moreover, the study classifies these regions into three types by their topography features and demonstrates that natural topographic conditions strongly influence the spatial patterns of anthropogenic landforms, underscoring the interplay between human modifications and the physical environment. This research provides a new perspective and robust methodological framework for analyzing the morphology pattern of anthropogenic landforms. It could be a data foundation for future studies exploring the interactions between human activities and geomorphological processes.

{"title":"Characterizing spatial patterns and regionalization of anthropogenic landforms using multi-source geospatial data: Insights from Loess Plateau of China","authors":"Yang Chen, Xin Yang, Huangjunxi Fu, Chenrui Li, Guoan Tang","doi":"10.1016/j.geomorph.2025.109708","DOIUrl":"10.1016/j.geomorph.2025.109708","url":null,"abstract":"<div><div>Anthropogenic forces have become a significant factor in the development of geomorphology, influencing landform morphology and usage in diverse ways across natural and societal environments. Despite their growing impact, few studies have quantified the morphology and distribution of anthropogenic landforms at large scales to reveal the spatial patterns of human modification on the surface. To address them, we propose a framework that includes three classical anthropogenic landforms, i.e., terraces, check dams, and impervious surfaces, on the Chinese Loess Plateau (CLP) to measure the morphology differences at the basin level. Using 10-meter resolution geospatial datasets, we conducted a quantitative analysis of spatial patterns across four landscape dimensions. We developed a scoring system based on the entropy-weight method to measure the intensity of anthropogenic landforms. Additionally, a data-driven clustering algorithm incorporating spatial dependence was applied to regionalize anthropogenic landforms. Our findings reveal significant spatial variations in the distribution of anthropogenic landforms. The east-central and west-central areas of the Loess Plateau exhibit clear signs of human modification, with high-intensity anthropogenic landforms concentrated near densely populated areas. The clustering effect of these landforms is particularly prominent in the central-eastern zones of the CLP due to the population and many soil and water conservation measures. By regionalizing anthropogenic landforms into eight distinct regions, each characterized by unique morphological features. Four regions are dominated by terraces; two regions are settlement-dominated and the others are mixed. Moreover, the study classifies these regions into three types by their topography features and demonstrates that natural topographic conditions strongly influence the spatial patterns of anthropogenic landforms, underscoring the interplay between human modifications and the physical environment. This research provides a new perspective and robust methodological framework for analyzing the morphology pattern of anthropogenic landforms. It could be a data foundation for future studies exploring the interactions between human activities and geomorphological processes.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"478 ","pages":"Article 109708"},"PeriodicalIF":3.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578800","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}

引用次数: 0

Cryokarst–induced dynamics of the Gangotri glacier, central Himalaya

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-07 DOI: 10.1016/j.geomorph.2025.109711

Bisma Yousuf , Aparna Shukla , Siddhi Garg , Shabir Ahmad Bangroo

The heterogenic debris-covered glacier surfaces are subject to differential ablation, favouring the formation of cryokarst features (such as supraglacial ponds and ice-cliffs). These features are investigated to explain the comparable and accelerated mass loss patterns for the Himalayan debris-covered and clean glaciers and can also exacerbate glacial hazards. This study provides the first cryokarst inventory (at 2.5–15 m spatial resolutions) for the extensively debris-covered Gangotri glacier, central Himalaya, with the focus on assessing their dynamics and contribution to the glacier mass loss. The inventory reveals that ponds cover about 7 % of the glacier ablation zone between 2000 and 2018, with a 43 % increase in both their count and area. However, ice-cliff coverage is relatively low (1 %), exhibiting 33 % reduction in their count and about 21 % reduction in their area between 2006 and 2018. Only few ice-cliffs are pond-associated and show 7 % reduction from 2006 to 2018. The frequency and coverage of these cryokarst features follow a similar decreasing pattern with increasing surface elevation, surface slope and feature size. These features are more frequent in lower ablation zone (LAZ: 4060–4700 m) and on gentle (4–8°) to moderate (8–16°) slopes as compared to upper ablation zone (UAZ: 4700–5100 m) and on gentler slopes. Tiny (<0.001 km²) to small (0.001–0.002 km²) cryokarst features are more frequent than larger (>0.0243 km²) ones, but area contribution is more from semi-medium (0.002–0.004 km²) to medium-sized (0.004–0.008 km²) features. Significant pond growth observed at higher elevations from previous to recent decades are associated with rising air and surface temperatures. Overall, supraglacial ponds and ice-cliffs contribute to about 21 % and 16 % of net ablation, respectively, in the debris-covered Gangotri glacier surface during 2000–2018. The observed higher mean mass loss of LAZ (showing maximal mean debris thickness of 0.32 m) than that of UAZ (with minimal mean debris thickness of 0.09 m) is further explained by higher prevalence of cryokarst features in LAZ than in UAZ.

{"title":"Cryokarst–induced dynamics of the Gangotri glacier, central Himalaya","authors":"Bisma Yousuf , Aparna Shukla , Siddhi Garg , Shabir Ahmad Bangroo","doi":"10.1016/j.geomorph.2025.109711","DOIUrl":"10.1016/j.geomorph.2025.109711","url":null,"abstract":"<div><div>The heterogenic debris-covered glacier surfaces are subject to differential ablation, favouring the formation of cryokarst features (such as supraglacial ponds and ice-cliffs). These features are investigated to explain the comparable and accelerated mass loss patterns for the Himalayan debris-covered and clean glaciers and can also exacerbate glacial hazards. This study provides the first cryokarst inventory (at 2.5–15 m spatial resolutions) for the extensively debris-covered Gangotri glacier, central Himalaya, with the focus on assessing their dynamics and contribution to the glacier mass loss. The inventory reveals that ponds cover about 7 % of the glacier ablation zone between 2000 and 2018, with a 43 % increase in both their count and area. However, ice-cliff coverage is relatively low (1 %), exhibiting 33 % reduction in their count and about 21 % reduction in their area between 2006 and 2018. Only few ice-cliffs are pond-associated and show 7 % reduction from 2006 to 2018. The frequency and coverage of these cryokarst features follow a similar decreasing pattern with increasing surface elevation, surface slope and feature size. These features are more frequent in lower ablation zone (LAZ: 4060–4700 m) and on gentle (4–8°) to moderate (8–16°) slopes as compared to upper ablation zone (UAZ: 4700–5100 m) and on gentler slopes. Tiny (<0.001 km<sup>2</sup>) to small (0.001–0.002 km<sup>2</sup>) cryokarst features are more frequent than larger (>0.0243 km<sup>2</sup>) ones, but area contribution is more from semi-medium (0.002–0.004 km<sup>2</sup>) to medium-sized (0.004–0.008 km<sup>2</sup>) features. Significant pond growth observed at higher elevations from previous to recent decades are associated with rising air and surface temperatures. Overall, supraglacial ponds and ice-cliffs contribute to about 21 % and 16 % of net ablation, respectively, in the debris-covered Gangotri glacier surface during 2000–2018. The observed higher mean mass loss of LAZ (showing maximal mean debris thickness of 0.32 m) than that of UAZ (with minimal mean debris thickness of 0.09 m) is further explained by higher prevalence of cryokarst features in LAZ than in UAZ.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"478 ","pages":"Article 109711"},"PeriodicalIF":3.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578801","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}

引用次数: 0

Sediment characteristics and provenance of riverine dunes on the lower Tora River in Qaidam Basin, China

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-05 DOI: 10.1016/j.geomorph.2025.109709

Xiao Zhang , Ping Yan , Xiaokang Liu , Miao Dong , Wenjie Yuan , Xiaoxu Wang , Caixia Zhang

A thorough understanding of the physicochemical characteristics and source materials of riverine dunes and their relationship with rivers provides deeper insights into desert evolution. Riverine dunes are widespread along the southern edge of the Qaidam Basin, China. However, accessing relevant regions poses challenges, and available data remain limited. This study analyzed the grain size, major elements, and trace elements of surface sediments in various riverbanks, dune types, and geomorphic units in the lower Tora River. The results indicated a significant correlation between the physicochemical properties of dune sediments in the study area and the surface sediments of adjacent regions, primarily comprising materials from nearby sources.

However, caution is required when interpreting weathering intensity using the Chemical Index of Alteration (CIA) at a given deposition site, particularly if the geochemical background is unknown or strongly affected by hydrological processes. The variations in surface sedimentary characteristics on either side of the river can be attributed to factors such as parent rock composition, fresh material input, vegetation, wind sorting, evaporation, and the obstruction of flowing water. Fluvial dominance, particularly during seasonal river activity within dune fields, restricted the upwind sediment transport. Furthermore, high surface salinity contributed to dune stabilization, ultimately altering the types of riverine dunes near the channel and downwind.

{"title":"Sediment characteristics and provenance of riverine dunes on the lower Tora River in Qaidam Basin, China","authors":"Xiao Zhang , Ping Yan , Xiaokang Liu , Miao Dong , Wenjie Yuan , Xiaoxu Wang , Caixia Zhang","doi":"10.1016/j.geomorph.2025.109709","DOIUrl":"10.1016/j.geomorph.2025.109709","url":null,"abstract":"<div><div>A thorough understanding of the physicochemical characteristics and source materials of riverine dunes and their relationship with rivers provides deeper insights into desert evolution. Riverine dunes are widespread along the southern edge of the Qaidam Basin, China. However, accessing relevant regions poses challenges, and available data remain limited. This study analyzed the grain size, major elements, and trace elements of surface sediments in various riverbanks, dune types, and geomorphic units in the lower Tora River. The results indicated a significant correlation between the physicochemical properties of dune sediments in the study area and the surface sediments of adjacent regions, primarily comprising materials from nearby sources.</div><div>However, caution is required when interpreting weathering intensity using the Chemical Index of Alteration (CIA) at a given deposition site, particularly if the geochemical background is unknown or strongly affected by hydrological processes. The variations in surface sedimentary characteristics on either side of the river can be attributed to factors such as parent rock composition, fresh material input, vegetation, wind sorting, evaporation, and the obstruction of flowing water. Fluvial dominance, particularly during seasonal river activity within dune fields, restricted the upwind sediment transport. Furthermore, high surface salinity contributed to dune stabilization, ultimately altering the types of riverine dunes near the channel and downwind.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"478 ","pages":"Article 109709"},"PeriodicalIF":3.1,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563153","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}

引用次数: 0

Mechanisms of sidewall collapse in fine gullies due to water erosion

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-05 DOI: 10.1016/j.geomorph.2025.109705

Wenbin Huang , Yongtao Wang , Caixia Fan , Xiangtian Xu , Yong Liu

The collapse of fine gully sidewalls significantly exacerbates soil erosion; however, the processes and mechanisms driving these collapses remain insufficiently studied. In this study, we developed a specialized slope erosion test system to examine fine gully sidewall collapses across varying slope angles, water head heights, and sidewall heights. Using 3D reconstruction, fixed grid coordinates, polyethylene trajectory tracing, and direct shear testing, we systematically captured and analyzed the collapse dynamics of fine gully sidewalls. Key findings indicate that capillary action and scouring contribute distinctly to the varied collapse morphology of fine gully sidewalls. Based on collapse test results, we derived an expression to characterize the soil moisture field, and using direct shear test data, we formulated an expression for the soil friction angle under varying moisture conditions. Further theoretical derivation yielded a method for accurately calculating the top crack location and critical collapse state. The findings presented herein establish a theoretical foundation essential for advancing erosion control strategies and preventive measures.

{"title":"Mechanisms of sidewall collapse in fine gullies due to water erosion","authors":"Wenbin Huang , Yongtao Wang , Caixia Fan , Xiangtian Xu , Yong Liu","doi":"10.1016/j.geomorph.2025.109705","DOIUrl":"10.1016/j.geomorph.2025.109705","url":null,"abstract":"<div><div>The collapse of fine gully sidewalls significantly exacerbates soil erosion; however, the processes and mechanisms driving these collapses remain insufficiently studied. In this study, we developed a specialized slope erosion test system to examine fine gully sidewall collapses across varying slope angles, water head heights, and sidewall heights. Using 3D reconstruction, fixed grid coordinates, polyethylene trajectory tracing, and direct shear testing, we systematically captured and analyzed the collapse dynamics of fine gully sidewalls. Key findings indicate that capillary action and scouring contribute distinctly to the varied collapse morphology of fine gully sidewalls. Based on collapse test results, we derived an expression to characterize the soil moisture field, and using direct shear test data, we formulated an expression for the soil friction angle under varying moisture conditions. Further theoretical derivation yielded a method for accurately calculating the top crack location and critical collapse state. The findings presented herein establish a theoretical foundation essential for advancing erosion control strategies and preventive measures.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"477 ","pages":"Article 109705"},"PeriodicalIF":3.1,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561789","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}

引用次数: 0

Hydraulic conditions for the propagation of pre-existing fracture in river bedrock and implication for landscape evolution

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-05 DOI: 10.1016/j.geomorph.2025.109707

Xi Zhang , Diansen Yang , Robert G. Jeffrey , Qifang Yin , Jin Luo

The growth of pre-existing bedrock fractures in running water plays an important role in landscape evolution. How fractures, formed by other geological processes, can be extended further by moderate water pressure to create blocks that can then be plucked by the flowing water is an open question. In this paper, the effect of hydrodynamic forcing on fracture growth that results in bedrock erosion is studied quantitatively to address this question. The fracturing process depends on the pre-existing fracture geometry, bedrock surface topology, local stresses, water flow rates and rock properties. A fracture-mechanics model coupling rock deformation and fluid flow is used to investigate the hydraulic conditions for propagation of a single pre-existing bedrock fracture. The numerical results show that fracture growth can occur and create fragments under the pressure levels for flow velocity of a few meters per second, which are comparable to those predicted by an empirical formula generated from the experiments of turbulent flow along a rough surface. The non-planar eroded blocks can be generated in the bedforms that have a reduced rock stiffness from weathering and are of an undulating morphology. The eroded block shapes are insensitive to slope angle, but depend on pre-existing fracture length and orientation, and rock fracture toughness. Under some conditions, the model predicts the fracture paths that extend deeply into massive rock. The fracture behaviors presented are useful for quantitative estimates of water-driven bedrock erosion rates.

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引用次数: 0

Reconstructing aeolian activities and borders shifts of the Gonghe Sandy Lands since the last Glacial Maximum

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2025-03-04 DOI: 10.1016/j.geomorph.2025.109706

Yunkun Shi , Chongyi E , Chunxia Xu , Wenting Yan , Yongjuan Sun , Zhaokang Zhang , Jing Zhang , Qiang Peng

Desert dune systems are vital components of Earth's surface landscapes. Understanding historical activities and delineating desert dune field boundaries under different climatic conditions are important for identifying both paleoenvironmental drivers and the likelihood of future reactivation. The Gonghe Sandy Lands (GSLs), situated in the northeastern Qinghai-Tibet Plateau, are at the convergence zone between the Westerlies and Asian monsoon, which are sensitive to climatic change. Consequently, GSLs are ideal regions for studying the response of the Earth's surface to environmental factors. A regional stratigraphic statistical model was developed using 30 aeolian profiles with 194 ages (including seven new profiles with 38 new optically stimulated luminescence ages) in the Gonghe Basin. Aeolian activities, climatic changes, and borders shifts in GSLs since the last Glacial Maximum (LGM) were reconstructed using the model together with other records. The results demonstrate that (1) Since the LGM, the Gonghe Basin has experienced a climatic transition from cold and dry to warm and humid, and then to mild and subhumid. Aeolian activity weakened then strengthened over the changing climatic conditions since 22 ka. (2) The spatial configurations of GSLs changed markedly throughout different periods. The area reached 3490 km² during the LGM, contracted to 903 km² during the Middle Holocene, and expanded again at 5.5 ka. (3) Climatic changes, human activities, and topographical constraints shaped the spatial patterns of the GSLs. Before the Middle Holocene, the dynamics were influenced by the monsoon system. In the late Holocene, human activity became an important factor affecting the spatial patterns of GSLs. Nevertheless, the influence of topographical constraints on the sand dune distribition in GSLs cannot be overlooked. The model outputs reflect the frequency of aeolian activities, independent of age errors, and are particularly suitable for sandy land regions that lack LGM ages.

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引用次数: 0