Geomorphology最新文献_第10页

New insights into the timing of the Yellow River flowing into the North China Plain: Evidence from detrital zircon UPb geochronology and heavy mineral assemblages of sediments

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-15 DOI: 10.1016/j.geomorph.2024.109570

Jilong Yang , Chaoyu Zhang , JingYou Wang , Guoqiao Xiao , Qinmian Xu , Ruisheng Chen , Haifan Yuan

Identifying the timing of the Yellow River flowing into the North China Plain (also referred to as the integration of the middle and lower reaches of the Yellow River or the integration of the Yellow River) is essential for understanding the evolutionary processes of the Yellow River and the North China Plain, as well as the interplay between tectonic deformations and climatic change in this region. This study investigated sediments from borehole S005, drilled in the Yellow River alluvial fan within the Kaifeng sag, Henan Province, using detailed magnetostratigraphic analysis, detrital zircon UPb geochronology, and heavy mineral assemblage analysis. The magnetostratigraphic and optically stimulated luminescence results reveal that sediments in borehole S005 span about 3.33 Ma. Of these sediments, those deposited after about 1.32 Ma exhibit similar detrital zircon UPb age spectra and heavy mineral assemblages to the sediments in the middle and upper reaches of the Yellow River, suggesting that the Yellow River has cut through the Sanmen Gorge and supplied sediments to the North China Plain since about 1.32 Ma. This study excludes the far-field effect of the Late Pliocene uplift of the northeastern Qinghai-Tibet Plateau on the integration of the Yellow River. Additionally, this study proposes that the integration of the Yellow River was triggered by the fluvial incision and headwater erosion associated with the drastic climatic change during the Pleistocene.

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引用次数: 0

Analysis of wave-cut notch formation using digital photogrammetry

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-14 DOI: 10.1016/j.geomorph.2024.109580

John Barlow

Sea cliffs form more than half of the world's coasts. In wave-dominated environments, recession is driven by abrasion and quarrying at the base of coastal slopes and the formation of a wave-cut notch. Although widely acknowledged, this process has rarely been quantified in the field and relationships with marine boundary conditions have not been established. This study demonstrates the use of digital photogrammetry to monitor the development of a wave-cut notch in Newhaven Chalk, located on the Sussex coast of England, over four years. Results indicate that the base of the notch is aligned to the elevation of peak wave energy. Analysis of the cumulative rate of notch erosion indicates an almost perfect positive correlation (r² = 0.976) with accumulated excess wave energy at the site. Efforts to remove the influence of mass wasting and burial improves this relationship (r² = 0.998). Although this study is site specific, these results offer the potential to improve our understanding of the process response of coastal cliff systems to changes in sea level and wave climate.

引用次数: 0

Discrepancies in dating the expansion of European glaciers during the Last Glacial Cycle

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-12 DOI: 10.1016/j.geomorph.2024.109566

Juan Ignacio López-Moreno, José M. García-Ruiz

One of the most important problems in glacial geomorphology is the disagreement regarding the dates of glacial advances. During the Last Glacial Maximum (LGM, ~29 to 19 ka), the generalised advance of mountain glaciers coincided with the greatest extent of ice in the large ice sheets of northern Europe and North America and with the lowest sea level during the Last Glacial Cycle (∼110 to 11.7 ka). The significant number of studies dealing with glacial chronologies during recent decades and improvements in dating techniques have provided a wide range of information about the evolution of European glaciers and the timing of major glacial advances that deposited different types of moraines, proglacial sediment (especially fluvioglacial and kame terraces, and sandar), and glaciolacustrine sediment. Several publications have synthesized data on the evolution of European glaciers as a starting point for analysis of synchronous or asynchronous patterns regarding the dates of glacial advances in European ice sheets and mountain glaciers. Thus, studies of the significant glacial advances during MIS 5, MIS 4, and MIS 3 have reported disparate dates, so available information only provides an incomplete understanding of the expansion of European glaciers. Some of these discrepancies were significant, such as the occurrence of advances at the end of MIS 3 in some mountains of southern Europe while the ice sheet occupied a very small area in the Scandinavian Peninsula. Other dating discrepancies, such as events during the LGM and the Oldest Dryas (Heinrich Stadial 1), are smaller but still relevant. The possible causes of these discrepancies include climatic differences between northern and southern Europe, the importance of local topographic factors, and the variety of dating techniques. This review does not include the Younger Dryas Stadial, because the short duration of this cold period does not reflect the occurrence of large disparities in the timing of glacier advances, and also because of the uncertainty ranges of the datings overlap with the onset of the Holocene and the end of the Bølling-Allerød.

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引用次数: 0

Geomorphosites and geomorphological maps applied to public use, tourism and natural heritage management in the Rio Lobos Natural Park (Spain)

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-12 DOI: 10.1016/j.geomorph.2024.109573

Enrique Serrano , María José González-Amuchastegui , Rosa María Ruiz-Pedrosa

Managing geotourism in natural protected areas is challenging, especially in rural areas facing depopulation and economic decline, as well as overcrowding in specific locations. Geotourism assessments of geomorphosites, previously inventoried and evaluated, is crucial for understanding potential public use and has been implemented worldwide. In this work conducted in Río Lobos Natural Park in Castilla y León, Spain, a geotourism assessment of geomorphosites was applied, and a geomorphological map was created to identify areas with geomorphological and landscape values while addressing overcrowding. The objective was to identify and evaluate geomorphosites using the geomorphological map as a tool for spatial management of Natural Protected Areas (NPAs) in crowded areas, integrating geomorphosites with tourism potential into the park's attractions. The geomorphological map facilitated the analysis of the territory, selection of key geomorphosites and areas of interest, and assessment of their tourism potential. Information from geomorphology and geomorphosites was used to develop a map highlighting areas with significant geomorphological and landscape values, useful for park managers and visitors.

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引用次数: 0

Morphologic and sedimentological signatures resulting from Hurricane Ian, southwest Florida, USA: Insight into intra-storm bidirectional sediment transport processes

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-12 DOI: 10.1016/j.geomorph.2024.109563

W. Mathew McCormick , Tiffany Roberts Briggs , Leanne Hauptman , Ping Wang

The extreme conditions associated with Hurricane Ian, a large Category 4 hurricane, led to unprecedented damage to the barrier islands of southwest Florida. This study investigates the morphologic changes and sedimentological signatures of deposits resulting from Hurricane Ian along both developed and undeveloped barrier islands through a combination of sediment cores and pre- and post-storm digital elevation models. Laterally extensive washover deposits, measured up to 74 cm thick, were formed during the intensification phase of the storm surge and were primarily controlled by the degree of development and vegetation density along barrier-island interiors. Storm deposit sedimentology was influenced by the degree of development and position relative to the dune crest, with a large inclusion of anthropogenic debris along developed barrier-island interiors. During the subsiding phase of the storm surge, short, straight channels and longer, dendritic ebb-scour channels, measuring up to 2.4 m in depth, were cut into newly formed storm deposits and antecedent washover deposits from previous storms, reflecting time-dependent bidirectional sediment transport processes during Hurricane Ian. The results of this study demonstrate how bidirectional processes throughout a single large storm event have significant implications for the preservation potential of new and existing washover deposits, presenting a potential setback for long-term barrier-island migration.

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引用次数: 0

Assessing environmental effects on yardang development in the Qaidam Basin: Findings based on large-scale mapping of yardangs

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-12 DOI: 10.1016/j.geomorph.2024.109575

Bowen Gao , Ninghua Chen , Deguo Zhang , Yaochen Xu , Xuhua Weng , Wenqi Gao , Xinhao Jiang

Yardangs are streamlined ridges that form in arid environments mainly driven by the aeolian process. However, the development and evolution of yardangs could also involve feedback among other factors like the substrate, underlying topography, and rainfall. Currently, there is limited consensus on how these factors affect yardang development at the landscape scale. In this work, based on very high spatial resolution remotely sensed imagery and deep learning techniques, we conducted a comprehensive mapping of yardangs across the immense yardang fields in the Qaidam Basin, NW China. Then we used the yardang coverage that is the percentage of yardang areas per gridded zone, to estimate the yardang abundance and its spatial distribution across the study site. Then the partial least squares-structural equation modeling (PLS-SEM) was employed to quantitatively analyze the relationships among yardang coverage and wind force (Wind), substrate weakness (Substrate), underlying topography complexity (Topography), and rainfall force (Rainfall). The results indicated that Rainfall had a significant constraining effect on yardang development, accounting for 34 % of the total effect in the model. In contrast, Substrate, Wind, and Topography exhibited positive effects on yardang development, contributing 31 %, 20 %, and 15 % of the total effect, respectively. A spatial clustering of yardang fields was then carried out using the response-based unit segmentation (REBUS) algorithm, demonstrating the spatial heterogeneity of how these factors contribute to yardang development in different regions. This study improved our understanding of the mechanisms of yardang formation and evolution under the control of multiple factors.

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引用次数: 0

Gypsum cave notches and their palaeoenvironmental significance: A combined morphometric study using terrestrial laser scanning, traditional cave mapping, and geomorphological observations

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-12 DOI: 10.1016/j.geomorph.2024.109576

Jorge Sevil-Aguareles , Luca Pisani , Veronica Chiarini , Tommaso Santagata , Jo De Waele

Terrestrial laser scanning has shown to be a very powerful method for the study and monitoring of caves. The high density of acquired points allows geostatistical methods to be used in the elaboration of large datasets on different depositional and erosional morphologies on cave walls, roof and floor. Here we describe a multidisciplinary morphometric study on cave wall morphologies and sediments in a multi-level gypsum cave system in the northern Apennines (Italy) with the objective of finding the direction of water flow that created these passages over hundred thousand years ago. The analysis of the traditional cave map (in long profile) suggests an overall, albeit very low, north-west inclination of the cave passages. However, other definitive indicators of flow direction, such as scallops, are absent which restricts the verification of this interpretation. The laser scanner-derived 3D point clouds of the cave wall notches of the main level have been analysed using different methods to verify the paleocurrent direction. However, statistical analyses of the point cloud data have yielded inconclusive results, even if most flow-related morphologies appear to be gently sloping towards north-west, where the present main cave entrance is found. Imbrication of fluvial sediments prevalently indicates the same direction. While no single method provided conclusive results on its own, the collective evidence strongly suggests an ESE to WNW paleocurrent flow, confirming the ancient resurgence nature of the cave gallery.

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引用次数: 0

Geomorphologic mapping and analysis of fault activities along the northern margin of the Yanfan Basin, China

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-10 DOI: 10.1016/j.geomorph.2024.109568

Jiajun Sun , Honglin He , Takashi Oguchi , Zhanyu Wei , Shuai Zhao , Yueren Xu , Yongqi Meng , Xiaodi Tan

The proximity of Beijing to active faults at the northeastern end of the Shanxi Rift System has heightened seismic concerns since the 1976 Tangshan M 7.8 earthquake. This study examines the 105-km-long northern margin fault of the Yanfan Basin in the rift system. Previous studies indicated that the alluvial fans and terraces along the fault have been displaced due to large earthquakes over the past ~30 ka. Analysis of 0.5 m resolution terrain data enabled the identification of six surface levels of alluvial fans and five river terraces. We measured 373 vertical displacements across these geomorphic features and grouped the distribution of these values into five categories based on their probability density. These groups correspond to repeated faulting events since ~14 ka, with data from prior paleoseismological studies aiding in dating these offsets. The most recent displacements are potentially linked to the 1484 M 6.8 Juyongguan and 1337 M 6.5 Huailai earthquakes. The ~2 m difference between the offset sets suggests that similar multiple seismic events could have caused each set. The empirical relationship between surface rupture length and earthquake magnitude for the recorded events indicates that the fault's complex geometry likely contributed to segmented ruptures during these events. This study highlights the need to scrutinize fault activity near densely populated regions.

{"title":"Geomorphologic mapping and analysis of fault activities along the northern margin of the Yanfan Basin, China","authors":"Jiajun Sun , Honglin He , Takashi Oguchi , Zhanyu Wei , Shuai Zhao , Yueren Xu , Yongqi Meng , Xiaodi Tan","doi":"10.1016/j.geomorph.2024.109568","DOIUrl":"10.1016/j.geomorph.2024.109568","url":null,"abstract":"<div><div>The proximity of Beijing to active faults at the northeastern end of the Shanxi Rift System has heightened seismic concerns since the 1976 Tangshan <em>M</em> 7.8 earthquake. This study examines the 105-km-long northern margin fault of the Yanfan Basin in the rift system. Previous studies indicated that the alluvial fans and terraces along the fault have been displaced due to large earthquakes over the past ~30 ka. Analysis of 0.5 m resolution terrain data enabled the identification of six surface levels of alluvial fans and five river terraces. We measured 373 vertical displacements across these geomorphic features and grouped the distribution of these values into five categories based on their probability density. These groups correspond to repeated faulting events since ~14 ka, with data from prior paleoseismological studies aiding in dating these offsets. The most recent displacements are potentially linked to the 1484 <em>M</em> 6.8 Juyongguan and 1337 <em>M</em> 6.5 Huailai earthquakes. The ~2 m difference between the offset sets suggests that similar multiple seismic events could have caused each set. The empirical relationship between surface rupture length and earthquake magnitude for the recorded events indicates that the fault's complex geometry likely contributed to segmented ruptures during these events. This study highlights the need to scrutinize fault activity near densely populated regions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109568"},"PeriodicalIF":3.1,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134103","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

Ephemeral geomorphodiversity: Conceptual debate, valuation, and heritage management

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-10 DOI: 10.1016/j.geomorph.2024.109569

Juan López Bedoya , Raúl A. Mikkan , Marcos Valcárcel Díaz

This work engages in a discussion on the concept of the ephemeral and the active in Geomorphology, serving as the foundation to explore the potentiality of its heritage aspect. Commencing with conceptual aspects to reach a well-considered definition, an attempt is made to classify ephemeral phenomena from three perspectives: the chronological, based on the duration of landforms; that related to geomorphological dynamics; and the recurrence of the phenomena that modify them. The proposed objective is for this classification to define and differentiate various types of ephemeral geomorphological heritage, enabling their proper assessment and management from an original and specific perspective.

Subsequently, the article directs its attention to the keys that allow for the comprehension and organization of ephemeral geomorphological heritage resources. It advocates for focusing on the scientific significance of these phenomena rather than their formal appearance. Emphasis is placed on their role as indicators of environmental and climatic changes, in addition to their value for education and raising awareness about current and future environmental challenges.

The conclusion is reached that the treatment of these resources requires a strategy tailored to their essence, as their changing and mobile nature hinders the use of management plans successfully applied to other types of heritage. The key lies in understanding that the evolution of landforms and their dismantling are not synonymous with degradation but represent another facet of heritage value to be enhanced through innovative techniques. A final compendium establishes the foundations underpinning this specific strategy, seeking to elevate this heritage to a status on par with other well-established heritage categories within the realm of Geomorphology.

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引用次数: 0

Analog modeling of landslide dynamics: Case study from the Andean Mesón Alto deposit, Central Chile (∼33°40′S)

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-12-10 DOI: 10.1016/j.geomorph.2024.109564

L. Pinto , S.A. Sepúlveda , C. Lefeuvre , C. Albornoz , J. Rhodes , P. Jara , P. Muñoz , K. Deckart

The Mesón Alto deposit in the Central Chilean Andes (∼33°40′S) is a large-volume rock avalanche deposit (∼4.5 km³) formed in a glacial valley, presenting four distinct lithological bands whose origin is uncertain. This study employs analog modeling to investigate the influence of different kinematic variables on the deposit characteristics of landslides inspired in the Mesón Alto deposit. Field mapping has identified two primary lithological groups in the Mesón Alto deposit: andesitic fragments from the Oligo-Miocene formation and Miocene granodioritic rocks. The deposit displays a complex distribution of materials, including areas with well-sorted and poorly sorted deposits and varying grain sizes, from very large blocks to a locally significant presence of fine sediments. We developed analog models using a custom device that simulates the fluvial and glacial valley topography, varying factors such as valley geometry (U- or V-valley), opposite slope angles, and the number and proportion of landslide events. The measured parameters for comparisons included the deposit's width, length, and vertical and horizontal distances from the landslide crown to the toe. Our results highlight that variations in valley geometry and the number of events significantly influence the observed deposit structure. The study's findings provide insights into the dynamics of large-volume landslides and contribute to understanding the Mesón Alto deposit's formation. Results suggest that its complexity is primarily driven by a combination of geomorphological factors and the number of rock avalanche events: U-valley in confined conditions and two events, with the first larger than the second (70 %–30 %). Our results shed light on the processes shaping the Mesón Alto deposit and offer a framework for interpreting similar deposits in other glacial valleys worldwide, enhancing our understanding of variables that potentially influence the distribution and characteristics of landslide deposits in diverse settings.

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引用次数: 0