Pub Date : 2025-02-24DOI: 10.1016/j.geomorph.2025.109689
Sebastián Granados-Bolaños, Nicola Surian
Active volcanic landscapes are among the most energetic sedimentary systems on Earth. Rivers that flow through these terrains are extremely dynamic and experience rapid changes in their channel morphology. Channel morphology classification in humid tropical contexts near to active volcanoes has received little attention within geomorphological science. We applied diverse remote sensing techniques and carried out field observations to characterize with high-spatial resolution the channel morphology of four rivers that drain from the Irazú-Turrialba Volcanic Complex located in Costa Rica. This particular environment has extreme precipitation events, frequent high-magnitude earthquakes, dense vegetation, and active volcanic activity. We found that this highly energetic landscape contains unusual single-thread and multithread channels with steep-slopes, high-confinement, and coarse sediments, mainly composed of boulders. We therefore review the applicability of existing channel morphology classification schemes to this particular environment. Our findings provide novel insights into fluvial geomorphology around active volcanoes with tropical humid climates.
{"title":"Channel morphology in an active volcanic complex under humid tropical conditions","authors":"Sebastián Granados-Bolaños, Nicola Surian","doi":"10.1016/j.geomorph.2025.109689","DOIUrl":"10.1016/j.geomorph.2025.109689","url":null,"abstract":"<div><div>Active volcanic landscapes are among the most energetic sedimentary systems on Earth. Rivers that flow through these terrains are extremely dynamic and experience rapid changes in their channel morphology. Channel morphology classification in humid tropical contexts near to active volcanoes has received little attention within geomorphological science. We applied diverse remote sensing techniques and carried out field observations to characterize with high-spatial resolution the channel morphology of four rivers that drain from the Irazú-Turrialba Volcanic Complex located in Costa Rica. This particular environment has extreme precipitation events, frequent high-magnitude earthquakes, dense vegetation, and active volcanic activity. We found that this highly energetic landscape contains unusual single-thread and multithread channels with steep-slopes, high-confinement, and coarse sediments, mainly composed of boulders. We therefore review the applicability of existing channel morphology classification schemes to this particular environment. Our findings provide novel insights into fluvial geomorphology around active volcanoes with tropical humid climates.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"477 ","pages":"Article 109689"},"PeriodicalIF":3.1,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512676","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}
Pub Date : 2025-02-21DOI: 10.1016/j.geomorph.2025.109679
Matthieu Herpoel , Charles Bielders , Pierre Baert , Adrien Michez , Jeroen Meersmans , Aurore Degré
In Northwestern Europe, sediment transport from agricultural fields to rivers has significant off-site impacts, influenced by connectivity between landscape elements. Sediment connectivity, assessed using the index of connectivity (IC) developed by Borselli et al. (2008), is shaped by landscape configuration, including features like field boundaries that divide land parcels. Effective management requires understanding these interactions to mitigate soil erosion. IC depends on factors enhancing (upstream area and slope) or impeding (downstream distance and impedance) connectivity, with impedance estimation being particularly challenging to quantify due to vegetation effects. This study proposes to refine the IC weighting factor by incorporating parcel connectivity, better reflecting agricultural landscape fragmentation's impact. Focusing on the Dyle sub-catchment in Belgium, we applied the Revised IC using high-resolution data (1 m × 1 m). Fragmented landscapes yield lower connectivity values, indicating greater sediment disconnection. This is especially pronounced along concentrated flow paths, where up to 49 % of the least connected flow paths are disconnected compared to non-fragmented setups. Isoline-based parcel fragmentation emerged as highly effective, promoting larger parcel sizes and better disconnection on concentrated flow paths. These results emphasize the opportunities for improved management of agricultural landscapes in order to reduce sediment connectivity through appropriate land use practices and parcel configurations. Furthermore, by identifying potential vegetation barriers at the intersection of concentrated flow paths and field boundaries, our analysis shows that around 40 % of these barriers consist of adjacent fields with the same crop. It highlights opportunities for more effective crop rotations strategies.
{"title":"Field patterns as game changers of the sediment connectivity","authors":"Matthieu Herpoel , Charles Bielders , Pierre Baert , Adrien Michez , Jeroen Meersmans , Aurore Degré","doi":"10.1016/j.geomorph.2025.109679","DOIUrl":"10.1016/j.geomorph.2025.109679","url":null,"abstract":"<div><div>In Northwestern Europe, sediment transport from agricultural fields to rivers has significant off-site impacts, influenced by connectivity between landscape elements. Sediment connectivity, assessed using the index of connectivity (IC) developed by Borselli et al. (2008), is shaped by landscape configuration, including features like field boundaries that divide land parcels. Effective management requires understanding these interactions to mitigate soil erosion. IC depends on factors enhancing (upstream area and slope) or impeding (downstream distance and impedance) connectivity, with impedance estimation being particularly challenging to quantify due to vegetation effects. This study proposes to refine the IC weighting factor by incorporating parcel connectivity, better reflecting agricultural landscape fragmentation's impact. Focusing on the Dyle sub-catchment in Belgium, we applied the Revised IC using high-resolution data (1 m × 1 m). Fragmented landscapes yield lower connectivity values, indicating greater sediment disconnection. This is especially pronounced along concentrated flow paths, where up to 49 % of the least connected flow paths are disconnected compared to non-fragmented setups. Isoline-based parcel fragmentation emerged as highly effective, promoting larger parcel sizes and better disconnection on concentrated flow paths. These results emphasize the opportunities for improved management of agricultural landscapes in order to reduce sediment connectivity through appropriate land use practices and parcel configurations. Furthermore, by identifying potential vegetation barriers at the intersection of concentrated flow paths and field boundaries, our analysis shows that around 40 % of these barriers consist of adjacent fields with the same crop. It highlights opportunities for more effective crop rotations strategies.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"477 ","pages":"Article 109679"},"PeriodicalIF":3.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512686","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}
Pub Date : 2025-02-21DOI: 10.1016/j.geomorph.2025.109677
Yanan Zhang , Xiaofei Hu , Xilin Cao , Zihao Yi , Qixin Ren , Xuan Deng
The East Kunlun Shan offers key insights into plateau growth on the northeastern Tibetan Plateau. However, the uplift history of this region over the past several million years remains poorly understood. To address this, we combined cosmogenic nuclide burial dating and K-feldspar pIRIR dating with geomorphic indices and valley morphology analyses to reconstruct the Quaternary uplift and sedimentary history along the Golmud and Kaimuqi Rivers. Our results show that river sediments began accumulating before 1.41 Ma, and their elevation, similar to or lower than the present Golmud River bed, indicates that the river reached its current level by this time. Cycles of sediment fill and downcutting since 1.41 Ma were primarily driven by climatic changes, as no bedrock incision was observed. Erosion rates (20–83 mm/ka), channel steepness indices, valley width, and valley floor width-valley height ratios consistently suggest minimal or no tectonic uplift over the past several million years. These findings confirm the inactivity of the North Kunlun Fault since the Quaternary and highlight the dominant role of long-term aridification and episodic wetting events in shaping the region's geomorphic evolution. This study provides crucial insights into the interplay between tectonic stability and climate, advancing our understanding of landscape evolution in tectonically stable regions of the Tibetan Plateau.
{"title":"Tectonic uplift recorded by the river terraces in the northern flank of East Kunlun Shan","authors":"Yanan Zhang , Xiaofei Hu , Xilin Cao , Zihao Yi , Qixin Ren , Xuan Deng","doi":"10.1016/j.geomorph.2025.109677","DOIUrl":"10.1016/j.geomorph.2025.109677","url":null,"abstract":"<div><div>The East Kunlun Shan offers key insights into plateau growth on the northeastern Tibetan Plateau. However, the uplift history of this region over the past several million years remains poorly understood. To address this, we combined cosmogenic nuclide burial dating and K-feldspar pIRIR dating with geomorphic indices and valley morphology analyses to reconstruct the Quaternary uplift and sedimentary history along the Golmud and Kaimuqi Rivers. Our results show that river sediments began accumulating before 1.41 Ma, and their elevation, similar to or lower than the present Golmud River bed, indicates that the river reached its current level by this time. Cycles of sediment fill and downcutting since 1.41 Ma were primarily driven by climatic changes, as no bedrock incision was observed. Erosion rates (20–83 mm/ka), channel steepness indices, valley width, and valley floor width-valley height ratios consistently suggest minimal or no tectonic uplift over the past several million years. These findings confirm the inactivity of the North Kunlun Fault since the Quaternary and highlight the dominant role of long-term aridification and episodic wetting events in shaping the region's geomorphic evolution. This study provides crucial insights into the interplay between tectonic stability and climate, advancing our understanding of landscape evolution in tectonically stable regions of the Tibetan Plateau.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"476 ","pages":"Article 109677"},"PeriodicalIF":3.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474606","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}
Pub Date : 2025-02-20DOI: 10.1016/j.geomorph.2025.109680
Andrew Green , Liam Meltzer , Andrew Cooper , Herman Labuschagne , Tamera Heeralal
The stratigraphic architecture and evolution of a bypass alluvial valley system on the wide and deep Namibian shelf is investigated using a dense, pseudo-3D grid of ultra high-resolution sub-bottom profiler data, high-resolution multibeam and backscatter data, and >4900 cores. The channel morphology is defined by changes in terrain slope, with steeper slopes hosting more sinuous and narrower channels. Nine seismic units were identified in the <10 m-thick fill. Acoustic basement of the area comprises Precambrian gneisses and schists of the Namaqua Metamorphic province, and schists, phyllites and quartzites of the Gariep belt. These crop out on the shelf and form the framework within which the valley is located. A subaerial unconformity developed during an episode of Late Campanian hinterland uplift during which the channel system was initiated.
The basal fills of the channels (Units B and C) comprise weathered and reworked derivatives of Unit A, namely saprolites and balls of mudrock that were reworked by tidal and wave processes. These represent a long-term hiatus (weathering episode and landscape exposure of the Lower Palaeocene), followed by the transgressive flooding and filling of the channels during surfzone migration. After a subsequent hiatus shallow marine sandstones were deposited during the Early Eocene. The remaining valley fill comprises unconsolidated sediment of varying size classes. A gravel body (granules to boulders) dominates this fill, and represents initial fluvial deposition, followed by reworking during multiple phases of transgression and regression up to and including the Holocene. The capping succession of sands and muds represents the modern sediments of the shoreface and shelf; however, these are constrained to the original valley form and reflect strong geological control and lack of accommodation on the valley interfluves.
The fill succession and architecture of this shelf bypass valley contrast markedly with incised valley fills, where multiple regressive transgressive cycles form compound valleys. It developed over a much longer period of geologic time, is dominated by transgressive sediments and stratigraphic surfaces, is exceptionally thin and lacks multiple incisions. The lack of connection to a terrestrial drainage system for at least the past million years has contributed to the lack of incision and scour of accumulated sediment during lowstands. Such a sequence in the geologic record could easily be misinterpreted if the overall valley depositional setting was not recognised. Given the occurrence of many contemporary low gradient and deep shelves along passive margins globally, as well as in the geologic record, such systems are certainly more common than presently thought.
{"title":"Anatomy and stratigraphic evolution of a shelf bypass valley system: Lessons from the Namibian continental shelf","authors":"Andrew Green , Liam Meltzer , Andrew Cooper , Herman Labuschagne , Tamera Heeralal","doi":"10.1016/j.geomorph.2025.109680","DOIUrl":"10.1016/j.geomorph.2025.109680","url":null,"abstract":"<div><div>The stratigraphic architecture and evolution of a bypass alluvial valley system on the wide and deep Namibian shelf is investigated using a dense, pseudo-3D grid of ultra high-resolution sub-bottom profiler data, high-resolution multibeam and backscatter data, and >4900 cores. The channel morphology is defined by changes in terrain slope, with steeper slopes hosting more sinuous and narrower channels. Nine seismic units were identified in the <10 m-thick fill. Acoustic basement of the area comprises Precambrian gneisses and schists of the Namaqua Metamorphic province, and schists, phyllites and quartzites of the Gariep belt. These crop out on the shelf and form the framework within which the valley is located. A subaerial unconformity developed during an episode of Late Campanian hinterland uplift during which the channel system was initiated.</div><div>The basal fills of the channels (Units B and C) comprise weathered and reworked derivatives of Unit A, namely saprolites and balls of mudrock that were reworked by tidal and wave processes. These represent a long-term hiatus (weathering episode and landscape exposure of the Lower Palaeocene), followed by the transgressive flooding and filling of the channels during surfzone migration. After a subsequent hiatus shallow marine sandstones were deposited during the Early Eocene. The remaining valley fill comprises unconsolidated sediment of varying size classes. A gravel body (granules to boulders) dominates this fill, and represents initial fluvial deposition, followed by reworking during multiple phases of transgression and regression up to and including the Holocene. The capping succession of sands and muds represents the modern sediments of the shoreface and shelf; however, these are constrained to the original valley form and reflect strong geological control and lack of accommodation on the valley interfluves.</div><div>The fill succession and architecture of this shelf bypass valley contrast markedly with incised valley fills, where multiple regressive transgressive cycles form compound valleys. It developed over a much longer period of geologic time, is dominated by transgressive sediments and stratigraphic surfaces, is exceptionally thin and lacks multiple incisions. The lack of connection to a terrestrial drainage system for at least the past million years has contributed to the lack of incision and scour of accumulated sediment during lowstands. Such a sequence in the geologic record could easily be misinterpreted if the overall valley depositional setting was not recognised. Given the occurrence of many contemporary low gradient and deep shelves along passive margins globally, as well as in the geologic record, such systems are certainly more common than presently thought.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"476 ","pages":"Article 109680"},"PeriodicalIF":3.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464455","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}
Pub Date : 2025-02-19DOI: 10.1016/j.geomorph.2025.109676
Lisa L. Ely , Alyssa D. DeMott , Bryon J. Free , Andrew C. Ritchie
The removal of Glines Canyon Dam on the Elwha River in western Washington, USA, from 2011 to 2014 introduced a 20-Mt pulse of stored sediment and logs into the downstream channel. We used terrestrial laser scanning, high-resolution orthoimages, and surveys of large wood (LW) and sediment grain-size distribution to quantify changes to the channel and LW in four different geomorphic settings spanning a 16-year period before, during, and after dam removal. The results provide insights into the role of site-specific geomorphology on the interplay among sediment size and supply, wood, and channel form in the aftermath of a dam removal. Sediment-size distribution, braiding index, and number of log jams rapidly reached new steady states. Other factors, such as channel sinuosity and log jam area, were still evolving six years after the dam was removed. The rate and type of river response was partially dictated by the geomorphic setting and the accumulation of LW. Complex reaches trapped more sediment and LW, initiating immediate changes in the channel count, position and lateral migration that continued to evolve through positive feedbacks. Single-channel sites experienced less initial erosion and deposition, but channel migration continued for years once it was underway. The post-dam sediment composition progressively shifted to a mixed size distribution midway between the armored cobbles when the dam was in place and the influx of primarily sand and fine gravel during dam removal. Reworking of sediment was most rapid in the first year after dam removal, especially at the site with the greatest channel complexity. The relation between log jams and channel divisions fundamentally changed. There were 11 log jams in the middle reach of the Elwha River downstream of Glines Canyon Dam, and all log jams associated with channel divisions occurred at the heads of stable, vegetated islands. During dam removal, the number of log jams rapidly increased to 86 and stabilized near that level in the post-dam period. While log jams on stable islands persisted, more were added at divisions around transient sediment bars, scattered across gravel bars, or outside of the active channel. Following a brief spike during dam removal, there was a net long-term increase of ∼10 % in the number of channel divisions associated with log jams. The sediment deposits, LW, vegetation, channel morphology and river discharge continued to cause adjustments within the fluvial system a decade after the start of dam removal. This state of greater variability could be the new equilibrium for years to come.
{"title":"Decadal-scale effects of a dam removal on channel geomorphology, sediment and large wood on the Elwha River, Washington, USA","authors":"Lisa L. Ely , Alyssa D. DeMott , Bryon J. Free , Andrew C. Ritchie","doi":"10.1016/j.geomorph.2025.109676","DOIUrl":"10.1016/j.geomorph.2025.109676","url":null,"abstract":"<div><div>The removal of Glines Canyon Dam on the Elwha River in western Washington, USA, from 2011 to 2014 introduced a 20-Mt pulse of stored sediment and logs into the downstream channel. We used terrestrial laser scanning, high-resolution orthoimages, and surveys of large wood (LW) and sediment grain-size distribution to quantify changes to the channel and LW in four different geomorphic settings spanning a 16-year period before, during, and after dam removal. The results provide insights into the role of site-specific geomorphology on the interplay among sediment size and supply, wood, and channel form in the aftermath of a dam removal. Sediment-size distribution, braiding index, and number of log jams rapidly reached new steady states. Other factors, such as channel sinuosity and log jam area, were still evolving six years after the dam was removed. The rate and type of river response was partially dictated by the geomorphic setting and the accumulation of LW. Complex reaches trapped more sediment and LW, initiating immediate changes in the channel count, position and lateral migration that continued to evolve through positive feedbacks. Single-channel sites experienced less initial erosion and deposition, but channel migration continued for years once it was underway. The post-dam sediment composition progressively shifted to a mixed size distribution midway between the armored cobbles when the dam was in place and the influx of primarily sand and fine gravel during dam removal. Reworking of sediment was most rapid in the first year after dam removal, especially at the site with the greatest channel complexity. The relation between log jams and channel divisions fundamentally changed. There were 11 log jams in the middle reach of the Elwha River downstream of Glines Canyon Dam, and all log jams associated with channel divisions occurred at the heads of stable, vegetated islands. During dam removal, the number of log jams rapidly increased to 86 and stabilized near that level in the post-dam period. While log jams on stable islands persisted, more were added at divisions around transient sediment bars, scattered across gravel bars, or outside of the active channel. Following a brief spike during dam removal, there was a net long-term increase of ∼10 % in the number of channel divisions associated with log jams. The sediment deposits, LW, vegetation, channel morphology and river discharge continued to cause adjustments within the fluvial system a decade after the start of dam removal. This state of greater variability could be the new equilibrium for years to come.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"478 ","pages":"Article 109676"},"PeriodicalIF":3.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578798","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}
Pub Date : 2025-02-18DOI: 10.1016/j.geomorph.2025.109656
Giorgi Boichenko , Eric Cowgill , Tea Godoladze , Timothy A. Stahl , Salome Gogoladze , Giorgi Merebashvili , Avtandil Okrostsvaridze , Raymond Torres , Steven Binnie , Benedikt Ritter
Near Tbilisi, Georgia, the Kura (Mtkvari) River flows across the junction between seismically active thrust belts in the Greater and Lesser Caucasus Mountains, near the locus of modern contractional strain within this sector of the Arabia-Eurasia collision. Here we describe and use a suite of fluvial terraces to explore the regional paleogeography, landscape evolution, and neotectonic development of the east end of the Adjara-Trialeti fold-thrust within the Lesser Caucasus. Specifically, we identified and mapped a suite of fluvial terraces within and around Tbilisi by integrating analyses of airborne LiDAR data with provenance observations from clast compositions and paleoflow directions from clast imbrication data. These data reveal three distinct types of fluvial strath terraces in the region: a main set from the Kura River and two secondary sets sourced from tributaries on its western (right) and eastern (left) banks. There are seventeen different elevation levels, with heights ranging from 10 to 690 m above the current river level of the Kura River. We infer that the Kura terraces are formed by local surface uplift above actively growing folds because they mainly occur in areas underlain by anticlines, therefore we find evidence of localized folding and faulting of terrace deposits. However, we are unable to determine if individual generations of terraces are folded, as this requires detailed terrace correlations that go beyond the initial mapping and dating, we report here. Based on our regional mapping and paleocurrent data, we conclude that the Kura River migrated over time from the northeast to the southwest. This migration is inferred to result from differential uplift in this part of the Adjara-Trialeti fold-thrust belt, with active collision between the Greater and Lesser Caucasus in the northeast causing enhanced surface uplift, pushing the river towards the southwest.
{"title":"Kura (Mtkvari) River terraces record fluvial response to the collision of the Greater and Lesser Caucasus thrust belts, Georgia","authors":"Giorgi Boichenko , Eric Cowgill , Tea Godoladze , Timothy A. Stahl , Salome Gogoladze , Giorgi Merebashvili , Avtandil Okrostsvaridze , Raymond Torres , Steven Binnie , Benedikt Ritter","doi":"10.1016/j.geomorph.2025.109656","DOIUrl":"10.1016/j.geomorph.2025.109656","url":null,"abstract":"<div><div>Near Tbilisi, Georgia, the Kura (Mtkvari) River flows across the junction between seismically active thrust belts in the Greater and Lesser Caucasus Mountains, near the locus of modern contractional strain within this sector of the Arabia-Eurasia collision. Here we describe and use a suite of fluvial terraces to explore the regional paleogeography, landscape evolution, and neotectonic development of the east end of the Adjara-Trialeti fold-thrust within the Lesser Caucasus. Specifically, we identified and mapped a suite of fluvial terraces within and around Tbilisi by integrating analyses of airborne LiDAR data with provenance observations from clast compositions and paleoflow directions from clast imbrication data. These data reveal three distinct types of fluvial strath terraces in the region: a main set from the Kura River and two secondary sets sourced from tributaries on its western (right) and eastern (left) banks. There are seventeen different elevation levels, with heights ranging from 10 to 690 m above the current river level of the Kura River. We infer that the Kura terraces are formed by local surface uplift above actively growing folds because they mainly occur in areas underlain by anticlines, therefore we find evidence of localized folding and faulting of terrace deposits. However, we are unable to determine if individual generations of terraces are folded, as this requires detailed terrace correlations that go beyond the initial mapping and dating, we report here. Based on our regional mapping and paleocurrent data, we conclude that the Kura River migrated over time from the northeast to the southwest. This migration is inferred to result from differential uplift in this part of the Adjara-Trialeti fold-thrust belt, with active collision between the Greater and Lesser Caucasus in the northeast causing enhanced surface uplift, pushing the river towards the southwest.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"476 ","pages":"Article 109656"},"PeriodicalIF":3.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445272","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}
Pub Date : 2025-02-18DOI: 10.1016/j.geomorph.2025.109678
Yuexin Liu , Ziyuan Wu , Gui Long , Xinqi Feng , Ping Lai , Zibin Fang , Wenwen Wu , Jiewen Xu , Guanjun Xu , Hua Tu , Hongwei Li , Wen Wang , Zhongping Lai
The North coastal South China Sea (SCS) contains densely populated deltaic and non-deltaic plains. While recent dating has advanced knowledge on land-sea interactions in deltaic areas, chronological data for non-deltaic plains remain lacking, hindering a full understanding of coastal evolution. This study establishes the first chronological framework since late-Pleistocene for Longjiang plain, a non-deltaic coastal plain shaped by wind, ocean and fluvial forces. Using quartz Optically Stimulated Luminescence (OSL) and radiocarbon (14C) dating on two cores, combined with Bayesian age-depth modeling, we identified depositional hiatuses between >123 ± 8 ka and ka and between >72 ± 4 ka and ~ ka, respectively. These hiatuses were attributed to intensive erosion during last glacial sea-level fall/low stands. Below the hiatuses are strongly weathered sediments. Post-hiatus aeolian deposition during ka– ka is linked to post-glacial sea-level rise. By contrast, aeolian deposition after ka successive to tidal deposition is likely triggered by local regression caused by increased sediment supply, favored by human activity since ~2.5 ka. Erosion during last glacial sea-level fall/low stands and aeolian deposition during the latest interglacial (Holocene) sea-level high stands, support the view that aeolian dunes preserved in modern coastal areas are mainly formed at sea-level high stands, rather than low stands. They also indicate that coastal erosion-accumulation cycles, controlled by eustatic sea-level fluctuation are not limited to deltas but may prevail in non-delta coasts. Quartz OSL sensitivity variations are observed in both cores and linked to provenance change, rework/redeposition by wind or Long-term chemical weathering.
{"title":"Response to sea-level change in a non-deltaic coastal plain: Insights from cores chronologies","authors":"Yuexin Liu , Ziyuan Wu , Gui Long , Xinqi Feng , Ping Lai , Zibin Fang , Wenwen Wu , Jiewen Xu , Guanjun Xu , Hua Tu , Hongwei Li , Wen Wang , Zhongping Lai","doi":"10.1016/j.geomorph.2025.109678","DOIUrl":"10.1016/j.geomorph.2025.109678","url":null,"abstract":"<div><div>The North coastal South China Sea (SCS) contains densely populated deltaic and non-deltaic plains. While recent dating has advanced knowledge on land-sea interactions in deltaic areas, chronological data for non-deltaic plains remain lacking, hindering a full understanding of coastal evolution. This study establishes the first chronological framework since late-Pleistocene for Longjiang plain, a non-deltaic coastal plain shaped by wind, ocean and fluvial forces. Using quartz Optically Stimulated Luminescence (OSL) and radiocarbon (<sup>14</sup>C) dating on two cores, combined with Bayesian age-depth modeling, we identified depositional hiatuses between >123 ± 8 ka and <span><math><msubsup><mn>7.6</mn><mrow><mo>−</mo><mn>0.6</mn></mrow><mrow><mo>+</mo><mn>0.7</mn></mrow></msubsup></math></span> ka and between >72 ± 4 ka and ~<span><math><msubsup><mn>5.1</mn><mrow><mo>−</mo><mn>0.9</mn></mrow><mrow><mo>+</mo><mn>1.2</mn></mrow></msubsup></math></span> ka, respectively. These hiatuses were attributed to intensive erosion during last glacial sea-level fall/low stands. Below the hiatuses are strongly weathered sediments. Post-hiatus aeolian deposition during <span><math><msubsup><mn>7.6</mn><mrow><mo>−</mo><mn>0.6</mn></mrow><mrow><mo>+</mo><mn>0.7</mn></mrow></msubsup></math></span> ka–<span><math><msubsup><mn>6.5</mn><mrow><mo>−</mo><mn>0.5</mn></mrow><mrow><mo>+</mo><mn>0.7</mn></mrow></msubsup></math></span> ka is linked to post-glacial sea-level rise. By contrast, aeolian deposition after <span><math><msubsup><mn>2.14</mn><mrow><mo>−</mo><mn>0.48</mn></mrow><mrow><mo>+</mo><mn>0.69</mn></mrow></msubsup></math></span> ka successive to tidal deposition is likely triggered by local regression caused by increased sediment supply, favored by human activity since ~2.5 ka. Erosion during last glacial sea-level fall/low stands and aeolian deposition during the latest interglacial (Holocene) sea-level high stands, support the view that aeolian dunes preserved in modern coastal areas are mainly formed at sea-level high stands, rather than low stands. They also indicate that coastal erosion-accumulation cycles, controlled by eustatic sea-level fluctuation are not limited to deltas but may prevail in non-delta coasts. Quartz OSL sensitivity variations are observed in both cores and linked to provenance change, rework/redeposition by wind or Long-term chemical weathering.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"476 ","pages":"Article 109678"},"PeriodicalIF":3.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438094","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}
Pub Date : 2025-02-14DOI: 10.1016/j.geomorph.2025.109663
Hanzhi Zhang, Yang Chen, Mengying Wu, Huayu Lu, Yao Gu, Jiang Wu
Reconstructing the spatial evolution of deserts is crucial to understand the forcing mechanisms of environment change in arid region and predicting the future behavior of deserts under global warming. The eolian deposits in the Chinese Loess Plateau (CLP) provide an unrivaled archive for reconstructing the evolutionary history of deserts. While the grain size of loess is traditionally employed as an indicator of desert expansion and contraction, it primarily reflects the dust source-to-sink distance. Since the dust source of the CLP includes multiple arid regions, it remains challenging to distinguish the specific processes of an individual desert based solely on grain size. In this work, we proposed a novel provenance-based model, which can quantitatively distinguish evolutionary process of a specific desert. This model is derived from a comprehensive analysis of the Last Glacial Maximum (LGM) across transects in the CLP, which reveals that the relative contributions from the Mu Us sand fields decreased exponentially with increasing distance from the desert. We demonstrate the robustness of this model through a test on grain-size and provenance data in Luochuan, middle CLP. Finally, we apply this model to reconstruct the temporal evolution at the desert margin (Zhenbeitai, ZBT) since ca. 110 ka, which demonstrates that the boundary of the Mu Us sand fields was located approximately 20–60 km away from the ZBT site at 110–80 ka, expanded to its modern boundary at around 60–16 ka, and retreated by roughly 20 km during the Holocene. The migration of the Mu Us sand fields were primarily controlled by regional precipitation changes. This suggests that adequate regional precipitation may stabilize sand fields under future climate scenarios.
{"title":"Spatial provenance distributions in the Chinese Loess Plateau and implication for reconstruction of desert margin","authors":"Hanzhi Zhang, Yang Chen, Mengying Wu, Huayu Lu, Yao Gu, Jiang Wu","doi":"10.1016/j.geomorph.2025.109663","DOIUrl":"10.1016/j.geomorph.2025.109663","url":null,"abstract":"<div><div>Reconstructing the spatial evolution of deserts is crucial to understand the forcing mechanisms of environment change in arid region and predicting the future behavior of deserts under global warming. The eolian deposits in the Chinese Loess Plateau (CLP) provide an unrivaled archive for reconstructing the evolutionary history of deserts. While the grain size of loess is traditionally employed as an indicator of desert expansion and contraction, it primarily reflects the dust source-to-sink distance. Since the dust source of the CLP includes multiple arid regions, it remains challenging to distinguish the specific processes of an individual desert based solely on grain size. In this work, we proposed a novel provenance-based model, which can quantitatively distinguish evolutionary process of a specific desert. This model is derived from a comprehensive analysis of the Last Glacial Maximum (LGM) across transects in the CLP, which reveals that the relative contributions from the Mu Us sand fields decreased exponentially with increasing distance from the desert. We demonstrate the robustness of this model through a test on grain-size and provenance data in Luochuan, middle CLP. Finally, we apply this model to reconstruct the temporal evolution at the desert margin (Zhenbeitai, ZBT) since ca. 110 ka, which demonstrates that the boundary of the Mu Us sand fields was located approximately 20–60 km away from the ZBT site at 110–80 ka, expanded to its modern boundary at around 60–16 ka, and retreated by roughly 20 km during the Holocene. The migration of the Mu Us sand fields were primarily controlled by regional precipitation changes. This suggests that adequate regional precipitation may stabilize sand fields under future climate scenarios.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"475 ","pages":"Article 109663"},"PeriodicalIF":3.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418922","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}
Pub Date : 2025-02-13DOI: 10.1016/j.geomorph.2025.109665
Hang Wu , Mark A. Trigg , William Murphy , Raul Fuentes
Dam-forming landslides are of significant interest to researchers, as only about 1 % of landslides block rivers, yet these dams can cause extreme flooding when they collapse, with flood flows up to ten times larger than extreme fluvial floods. While regional studies have noted differences in the dimensional characteristics and formation indices between dam-forming and non-dam-forming landslides, a global quantitative comparison has not yet been made. Using open-access global datasets, we conducted a statistical analysis of their morphometric and spatial characteristics, including volume, height/length ratio, and geomorphological factors. Spatial clustering analysis was also performed to determine whether certain landslides are more likely to form dams. The results indicate that dam-forming landslides are a distinct subset: (i) they occur in more upstream areas with higher stream power index values; (ii) they have lower mobility, confined by steeper slopes and shorter hillslope lengths; (iii) shallower landslides with larger surface area and sufficient volume are more likely to form dams; and (iv) they exhibit different spatial clustering patterns compared to general landslides. Despite some data limitations, this global study provides a foundation for quantifying a landslide dam formation index and identifying areas prone to dam formation.
{"title":"Analysis of the fundamental differences between dam-forming landslides and all landslides","authors":"Hang Wu , Mark A. Trigg , William Murphy , Raul Fuentes","doi":"10.1016/j.geomorph.2025.109665","DOIUrl":"10.1016/j.geomorph.2025.109665","url":null,"abstract":"<div><div>Dam-forming landslides are of significant interest to researchers, as only about 1 % of landslides block rivers, yet these dams can cause extreme flooding when they collapse, with flood flows up to ten times larger than extreme fluvial floods. While regional studies have noted differences in the dimensional characteristics and formation indices between dam-forming and non-dam-forming landslides, a global quantitative comparison has not yet been made. Using open-access global datasets, we conducted a statistical analysis of their morphometric and spatial characteristics, including volume, height/length ratio, and geomorphological factors. Spatial clustering analysis was also performed to determine whether certain landslides are more likely to form dams. The results indicate that dam-forming landslides are a distinct subset: (i) they occur in more upstream areas with higher stream power index values; (ii) they have lower mobility, confined by steeper slopes and shorter hillslope lengths; (iii) shallower landslides with larger surface area and sufficient volume are more likely to form dams; and (iv) they exhibit different spatial clustering patterns compared to general landslides. Despite some data limitations, this global study provides a foundation for quantifying a landslide dam formation index and identifying areas prone to dam formation.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"475 ","pages":"Article 109665"},"PeriodicalIF":3.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429883","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}
Pub Date : 2025-02-13DOI: 10.1016/j.geomorph.2025.109669
John J. Clague , Brendan Miller
River terraces are ubiquitous in the formerly glaciated valleys of British Columbia, where they are commonly interpreted as products of Holocene incision of paraglacial valley fills. In this paper, we describe and interpret terrace sequences on the former floor of glacial Lake Fraser, the largest Late Pleistocene glacier-dammed lake in British Columbia. Postglacial terraces up to 120 m above the present lower Nechako and Fraser River valley floors are the dominant landforms within the former lake basin. In this paper, we focus on the Nechako River terraces between Stuart River and Prince George, a distance of about 85 km. Our reconstruction and analysis are based on high-resolution lidar imagery and field investigation of sediments exposed beneath the terraces. The highest, unpaired terraces are mainly erosional landforms developed on glacial Lake Fraser glaciolacustrine sediments, but are ornamented with low biconvex flood bars and linear erosional channels. As water drained rapidly eastward out of the lake, thin flows of fluidized lacustrine silt and sand derived from adjacent valley walls were deposited on the highest terraces and flood dunes formed below the lowest paleo-lake shorelines. At the same time, huge amounts of sediment were stripped from the emergent valley walls by landslides and gullying. This large and rapid flux of sediment provided thick gravel and sand that underlie lower Nechako Valley terraces. The lowest terraces have meandering channel forms that are markedly different from the streamlined high terrace surfaces. About 200 kettles in six clusters on mid- and low-level terraces in Nechako Valley mark locations of ice blocks that calved from the stagnating front of the remnant Cordilleran Ice Sheet to the west and became stranded on the floor of glacial Lake Fraser. The distribution of the kettles shows that Nechako and, by inference, Fraser rivers were flowing within a few metres of their present levels within years to several decades after glacial Lake Fraser drained, which challenges the common assumption implicit in the paraglacial model that the terraces developed more slowly throughout the Holocene.
{"title":"Rapid and large-scale landscape modification caused by the draining of a glacier-dammed lake in British Columbia, Canada","authors":"John J. Clague , Brendan Miller","doi":"10.1016/j.geomorph.2025.109669","DOIUrl":"10.1016/j.geomorph.2025.109669","url":null,"abstract":"<div><div>River terraces are ubiquitous in the formerly glaciated valleys of British Columbia, where they are commonly interpreted as products of Holocene incision of paraglacial valley fills. In this paper, we describe and interpret terrace sequences on the former floor of glacial Lake Fraser, the largest Late Pleistocene glacier-dammed lake in British Columbia. Postglacial terraces up to 120 m above the present lower Nechako and Fraser River valley floors are the dominant landforms within the former lake basin. In this paper, we focus on the Nechako River terraces between Stuart River and Prince George, a distance of about 85 km. Our reconstruction and analysis are based on high-resolution lidar imagery and field investigation of sediments exposed beneath the terraces. The highest, unpaired terraces are mainly erosional landforms developed on glacial Lake Fraser glaciolacustrine sediments, but are ornamented with low biconvex flood bars and linear erosional channels. As water drained rapidly eastward out of the lake, thin flows of fluidized lacustrine silt and sand derived from adjacent valley walls were deposited on the highest terraces and flood dunes formed below the lowest paleo-lake shorelines. At the same time, huge amounts of sediment were stripped from the emergent valley walls by landslides and gullying. This large and rapid flux of sediment provided thick gravel and sand that underlie lower Nechako Valley terraces. The lowest terraces have meandering channel forms that are markedly different from the streamlined high terrace surfaces. About 200 kettles in six clusters on mid- and low-level terraces in Nechako Valley mark locations of ice blocks that calved from the stagnating front of the remnant Cordilleran Ice Sheet to the west and became stranded on the floor of glacial Lake Fraser. The distribution of the kettles shows that Nechako and, by inference, Fraser rivers were flowing within a few metres of their present levels within years to several decades after glacial Lake Fraser drained, which challenges the common assumption implicit in the paraglacial model that the terraces developed more slowly throughout the Holocene.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"475 ","pages":"Article 109669"},"PeriodicalIF":3.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418805","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}
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