18,495 results on '"Landforms"'
Search Results
2. Site U1595.
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Druitt, H., Kutterolf, S., Ronge, T. A., Beethe, S., Bernard, A., Berthod, C., Chen, H., Chiyonobu, S., Clark, A., DeBari, S., Fernandez Perez, T. I., Gertisser, R., Hübscher, C., Johnston, R. M., Jones, C., Joshi, K. B., Kletetschka, G., Koukousioura, O., Li, X., and Manga, M.
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SEA level ,VOLCANOES ,LANDFORMS - Published
- 2024
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3. Occupation patterns during the Shangshan in the upper Qiantang River Basin, eastern China: A geomorphic study based on GIS.
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Zhang, Wenjia, Lin, Zhou, Jiang, Leping, Ding, Chao, Chen, Meiling, Zhou, Shengchao, and Zhao, Xiang
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FLOOD risk , *LANDFORMS , *TERRACES (Geology) , *SETTLING basins , *FARMS , *WATERSHEDS - Abstract
Shangshan is the earliest Neolithic culture discovered in the lower Yangtze region and is significant as one of the origins of rice agriculture worldwide. During the Early Holocene, the Shangshan human groups settled in the river basins of the upper Qiantang region and transitioned from hunter-gatherers to farmers. Little is known about the dominant factors motivating them to settle down and their occupation patterns for adapting to local environments. To address these issues, we applied an ad hoc method by coupling landform classification, geomorphic fieldwork, accessibility analysis, and flood risk assessment. The results of geomorphic and accessibility analyses show that the ancient residents preferred to occupy the edges of the Middle Pleistocene terraces along second- and third-order streams. These locations are mainly situated in the centers of river basins and have height differences of 5–15 m, less than approximately 15-min walking distance from streams, providing them with stable residential spaces and accessible water resources. Within the 10-min territorial scope, there are always some fluvial plains near the terrace edges, indicating that the plain is another critical landform utilized by the residents. The wide plains and a plain-terrace-upland geomorphic assemblage, within 1-h and 2-h scopes, respectively, imply that the residents started to develop agricultural land while they also exploited diverse environments to ensure a plentiful food supply. Furthermore, the hydrologic analysis and assessment reveal that the residents were aware of the potential flood risks: their settlements are located at 30-min walking distance or greater from the high-order streams; most sites are exposed to low flood risks, with average percentages of unflooded territory greater than 67% and 43% in the minor and large flood scenarios, respectively; and each site has sufficient arable land with areas of 5–23 km2 within a 1-h scope, even under the large flood scenario. Overall, these results reveal that the river basins provided favorable living environments, and the residents could flexibly manage the landscapes to ensure stable settlements and food production, thus enabling the appearance and development of a sedentary society and rice agriculture during the early Holocene. Ultimately, the methods used in this study provide an effective approach to exploring the occupation patterns of prehistoric residents in the river basins. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Integrating terrain structure characteristics into generative adversarial nets for hillshade generation.
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Yan, Lingrui, Ai, Tinghua, and Gao, Aji
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GENERATIVE adversarial networks , *CONVOLUTIONAL neural networks , *MOTOR ability , *LANDFORMS , *MILLENNIALS - Abstract
AbstractA hillshade is a visualization technique that represents three-dimensional terrain in a two-dimensional plane by illumination mapping. The digital relief shading promotes the visualization of the terrain efficiently using DEM data. However, compared with manual shading, the digital algorithm-based method still has a gap in the visual effect of illumination strategy and terrain generalization. The typical landform characteristics and micro-geomorphic properties usually are destroyed. The reason is that the complexity of illumination rules is hard to summarize for different terrain phenomena. In this study, namely the data-driven artificial intelligent method, an alternative strategy based on generative adversarial networks (GANs) is proposed rather than the rule-based method. The DEM and the terrain skeleton lines are input to the model and part of the manual relief shading of Swisstopo is used for the training samples. Through the GAN training and learning, the manual skill imbedded in the hillshade is discovered in the generation model. The results show that the proposed model performs better than the digital relief shading on various landforms in aesthetic visualization and geo-scientific representation. Compared to other models, including other convolution neural network (CNN) based methods, terrain structure is maintained more significantly through the proposed model. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Accuracy and hydrographic realism of an under-forest DEM derived from airborne P-band radar interferometry over a wide area in the Brazilian amazon.
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Caldeira, Carlos Rodrigo Tanajura, El Hage, Mhamad, da Silva Rosa, Rafael Antonio, and Polidori, Laurent
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RADAR interferometry , *AIRBORNE-based remote sensing , *RADAR in aeronautics , *LIDAR , *DIGITAL elevation models , *STANDARD deviations , *OPTICAL radar , *SPACE-based radar - Abstract
P-band radar interferometry is a promising tool for digital terrain modelling in forested areas such as the Amazon due to the ability of P-band to penetrate densely forested areas. The quality of Digital Terrain Models (DTMs) is a primary requirement for many geoscience applications because DTM accuracy is an essential variable for characterizing landform shapes. This article presents a multicriteria evaluation of the overall quality of a digital terrain model produced using P-band SAR interferometric processing. The evaluation considers behaviours related to elevation and slope and analyses the impact of landscape properties such as slope and aspect. The multicriteria accuracy of the study showed promising results about the realism of landforms, according to applied geomorphological criteria, and also in the visual comparison between the produced DTM and the reference. The study provided an estimate of the accuracy of P-band radar DTM in terms of elevation with a standard deviation of 2.36 m and in terms of slope with a mean error of approximately −4°, a standard deviation of 4.74°, and a RMSE (Root Mean Square Error) slope error of 6.14°, using a reference DTM derived from an airborne LiDAR (Light Detection and Ranging) survey. The spatial behaviour of these errors and their sensitivity to slope and aspect were analysed. The investigation of hydrographic inconsistencies in the DTM was conducted based on various criteria, including identifying depressions along watercourses and adhering to Horton's law. Finally, the effects of the acquisition, processing, and resampling processes are revealed through indicators such as the rose histogram. This multicriteria study demonstrates the suitability of airborne P-band radar interferometry for digital elevation modelling in tropical rainforest environments. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Quaternary Activity Characteristics and Regional Tectonic Significance of the Jiulong Fault in Jiujiang, Jiangxi Province, China.
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Qi, Xin, Jiao, Yuyong, Li, Qinghua, and Li, Bin
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GEOLOGICAL surveys , *EARTHQUAKE magnitude , *OPTICALLY stimulated luminescence dating , *ACTIVE aging , *LANDFORMS , *ELECTRON spin resonance dating , *FAULT zones - Abstract
Obtaining geological and landform dislocation features, as well as the measured stratigraphic activity age, provides direct evidence to evaluate fault activity, which is more difficult to do in areas with low tectonic activity, such as eastern and central China. A detailed investigation of the fault activity, trenching, drilling joint geological profile, geological survey, and chronological analysis were used to obtain the spatial geometry, fault kinematics, and activity chronology of the Jiulong fault. The conclusions are as follows: (1) The Jiulong fault was a fracture zone composed of four branch faults, with a width of around 30–40 m and good extendibility, while the maximum surface rupture length was 373 m. (2) The Jiulong fault has many strata dislocations, and the dislocation distance decreased from bottom to top, demonstrating synsedimentary structure characteristics, with a maximum stratigraphic dislocation distance of 18.2 m. (3) Preliminary analysis suggested the Jiulong fault as a secondary fracture of the Xiangfan-Guangji fault zone and provided evidence of the southeastward extension of the Xiangfan-Guangji fault. A preliminary hypothesis purported the Xiangfan-Guangji fault as the seismogenic fault of the Ms 5.0 magnitude earthquake in 1911. (4) According to OSL and ESR dating analyses, the upper breakpoint of the Jiulong fault cuts into the Late Pleistocene Xingang Formation (Qp3x) strata, and the latest active age of the Jiulong fault was 57.6 ka. The chronology analysis confirmed an active fault from the Late Pleistocene and identified a weak tectonic in Jiujiang Province, which represents the largest active fault outcrop uncovered in the area so far. This study provides evidence and research materials for the evaluation of fault activity and seismic stability in this region. [ABSTRACT FROM AUTHOR]
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- 2024
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7. A Comparison of Landforms and Processes Detection Using Multisource Remote Sensing Data: The Case Study of the Palinuro Pine Grove (Cilento, Vallo di Diano and Alburni National Park, Southern Italy).
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Valiante, Mario, Di Benedetto, Alessandro, and Aloia, Aniello
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GEOMORPHOLOGICAL mapping , *DIGITAL elevation models , *REMOTE sensing , *DIGITAL mapping , *LANDFORMS - Abstract
The automated recognition of landforms holds significant importance within the framework of digital geomorphological mapping, serving as a pivotal focal point for research and practical applications alike. Over the last decade, various methods have been developed to achieve this goal, ranging from grid-based to object-based approaches, covering a range from supervised to completely unsupervised techniques. Furthermore, the vast majority of the methods mentioned depend on Digital Elevation Models (DEMs) as their primary input, highlighting the crucial significance of meticulous preparation and rigorous quality assessment of these datasets. In this study, we compare the outcomes of grid-based methods for landforms extraction and surficial process type assessment, leveraging various DEMs as input data. Initially, we employed a photogrammetric Digital Terrain Model (DTM) generated at a regional scale, along with two LiDAR datasets. The first dataset originates from an airborne survey conducted by the national government approximately a decade ago, while the second dataset was acquired by UAV as part of this study's framework. The results highlight how the higher resolution and level of detail of the LiDAR datasets allow the recognition of a higher number of features at higher scales; but, in contrast, generally, a high level of detail corresponds with a higher risk of noise within the dataset, mostly due to unwanted natural features or anthropogenic disturbance. Utilizing these datasets for generating geomorphological maps harbors significant potential in the framework of natural hazard assessment, particularly concerning phenomena associated with geo-hydrological processes. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Exploring the Composition of Europa with the Upcoming Europa Clipper Mission.
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Becker, T. M., Zolotov, M. Y., Gudipati, M. S., Soderblom, J. M., McGrath, M. A., Henderson, B. L., Hedman, M. M., Choukroun, M., Clark, R. N., Chivers, C., Wolfenbarger, N. S., Glein, C. R., Castillo-Rogez, J. C., Mousis, O., Scanlan, K. M., Diniega, S., Seelos, F. P., Goode, W., Postberg, F., and Grima, C.
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SPACE environment , *SEAWATER , *REMOTE sensing , *LANDFORMS , *JUPITER (Planet) - Abstract
Jupiter's icy moon, Europa, harbors a subsurface liquid water ocean; the prospect of this ocean being habitable motivates further exploration of the moon with the upcoming NASA Europa Clipper mission. Key among the mission goals is a comprehensive assessment of the moon's composition, which is essential for assessing Europa's habitability. Through powerful remote sensing and in situ investigations, the Europa Clipper mission will explore the composition of Europa's surface and subsurface, its tenuous atmosphere, and the local space environment surrounding the moon. Clues on the interior composition of Europa will be gathered through these assessments, especially in regions that may expose subsurface materials, including compelling geologic landforms or locations indicative of recent or current activity such as potential plumes. The planned reconnaissance of the icy world will constrain models that simulate the ongoing external and internal processes that act to alter its composition. This paper presents the composition-themed goals for the Europa Clipper mission, the synergistic, composition-focused investigations that will be conducted, and how the anticipated scientific return will advance our understanding of the origin, evolution, and current state of Europa. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Viola fuscopurpurea (Violaceae), a new species from Chongqing, China.
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Dai, Jingmin, Yi, Si‐Rong, Huang, Yanshuang, Zhang, Hong‐Jing, and Fan, Qiang
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LANDFORMS , *NECTARIES , *VIOLACEAE , *VIOLA , *PHYLOGENY - Abstract
Viola fuscopurpurea (Violaceae), a new species from Karst landform of Chongqing in China, is described and illustrated. The new species is most similar toV. fukienensis , but can be distinguished by nearly glabrous, shiny, adaxially purple blades (vs pubescent, adaxially green blades), brown seeds with conspicuous tubercles (versus yellow seeds with smooth surface), and hook‐like nectaries (versus triangular nectaries), as well as by general habit. Our phylogenetic analysis, based on ITS sequences, confirms that the new species belongs toV . subsect.Rostratae , and is most closely related toV. fukienensis in the phylogeny. [ABSTRACT FROM AUTHOR]- Published
- 2024
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10. Circular genetic structure of the Abies nephrolepis species complex shaped by the circular landform of Northeast Asia.
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Kwak, Myounghai, Nakamura, Koh, Xiang, Qiaoping, Wen, Jun, Lee, Eun Sil, Hong, Jaram, Kovtonyuk, Nataliya, Kryukova, Maria, Korchagina, Olga, Koo, Kyung Ah, Iwaizumi, Masakazu G., Lee, Byoung Yoon, Kokubugata, Goro, Zhang, Xianchun, and Lebedev, Dmitry
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MICROSATELLITE repeats , *CHLOROPLAST DNA , *LANDFORMS , *FIR , *SPECIES , *SINGLE nucleotide polymorphisms , *GENETIC distance , *GENE flow ,REPRODUCTIVE isolation - Abstract
Aim: Pinaceae have been noted for their tendency towards reticulation as a result of interspecific hybridization. Here, we demonstrated the phylogeographic dynamics of the native Northeast Asian sub‐alpine conifer, Abies nephrolepis species complex (ANSC), evolving in circular overlaps along the Northeast Asian landform, which functions as a corridor with the sea, thus acting as a geographic barrier. Location: Northeast Asia: the Korean Peninsula, Japanese Archipelago, Russian Far East and northeastern China. Taxon: Abies nephrolepis species complex (Family Pinaceae, Genus Abies, Section Balsamea, Abies nephrolepis, A. koreana, A. veitchii and A. sachalinensis). Methods: A total of 728 individuals from 38 ANSC populations were analysed using multiplexed inter‐simple sequence repeat genotyping by sequencing to capture variations in biparental nuclear genomes. Eight mitochondrial regions and eight chloroplast regions of each individual were sequenced using the MiSeq platform and Sanger sequencing. Species distribution models were generated. Results: Bayesian clustering with 507 nuclear single nucleotide polymorphisms and the discrepancy between cytoplasmic and nuclear genome lineages implied contemporary and ancient connections between neighbouring species in the form of circular overlap. This genetic connectivity was supported by principal component analysis. Strong correlations between genetic distance and geographic distance were observed, suggesting that gene flow occurs through a continuous chain around the sea. We also found that gene flow direction and intensity changed over time, with support from palaeodistribution modelling. Conclusion: Past hybridization events were captured in cytoplasmic genomes, generating heterogeneity across maternal ancestries. This intensive phylogeographic study demonstrates speciation with incomplete reproductive isolation (continuous gene flow) among neighbouring species with an alteration of the direction and intensity of gene flow due to climate change. The divergence of ANSC due to repeated isolation and reconnection caused by heterogenous physiological environments and climate fluctuation provides a model to solve evolutionary scenarios for reticulate evolution in Pinaceae and other plants. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Potential for Events Similar to the Deadly West Salt Creek Landslide, Grand Mesa Area, Colorado.
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ARABNIA, OMID, SANTI, PAUL, EMMONS, BENNETT, and SPARKS, EMILY
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DEBRIS avalanches ,LANDFORMS ,CANYONS ,SALT ,MORPHOLOGY ,LANDSLIDES - Abstract
The deadly West Salt Creek Landslide of 2014, one of the largest landslides to occur in the United States in historical time, was surprising in its suddenness and length of runout. Its source area, the edge of Grand Mesa in western Colorado, was potentially the source of other similar landslides in the past, based on previous mapping in the region. The purpose of this research was to evaluate the potential for similar events by detailed mapping of several canyons flanking West Salt Creek, using aerial imagery and age-dating techniques not available to previous mappers. We conclude that, while the West Salt Creek Landslide has the potential to reactivate in a similar manner to the 2014 movement, the potential for a similar event in the flanking canyons is low. Mapping and semi-quantitative geomorphic methods suggest that the deposits present in several canyons on either side of West Salt Creek are glacial or stream deposits, with one canyon containing debris-flow deposits. Our interpretations are based on the morphology of deposits in the canyons, the presence of specific landform features, measurements of mobility index and longitudinal profiles, and comparison with regional analogs. Furthermore, other mass movements in the region that are of similar magnitude had either slower movement or much shorter runout. The large block at the head of West Salt Creek and the earlier block that shattered and mobilized in 2014 are also unique features locally, distinguishing this setting from others, but also indicating the potential for a future similar event. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Particle size characterization and sources of sediments in the Uzhumqin sand dunes.
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Zhang, Hao, Liu, Yang, Dang, Xiaohong, Meng, Zhongju, Li, Shuangli, and Gao, Yong
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LAKE sediments ,RIVER sediments ,FRACTAL dimensions ,LANDFORMS ,SOIL particles ,SAND dunes - Abstract
Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology. The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain, making their study critical to understanding aeolian geomorphology and sand control. In this study, we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this region. In addition, we used an end-member analysis to identify the potential sources of the sediments. The results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial distributions. Medium and coarse grain sands dominated the sediments in the dunes, and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction, with high values in individual areas related to factors such as material sources and vegetation cover. Skewness was strongly influenced by factors such as landform change and human activity, and spatial variability became more complex. Kurtosis and the soil fractal dimension showed generally decreasing trends along the prevailing wind direction. With dune fixation, the contents of clay and powder particles in the soil increased; the mean particle size, the sorting coefficient, and the fractal dimension of the soil gradually increased, and the skewness and kurtosis gradually decreased. The end-member analysis results indicated the existence of five end-members (EM) in the dune sediments. EM 1 was a mixed component of wind-deposited fine sands and nearby fluvial sediments. EM 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local topography. EM 3 may be a product of river flood deposition. EM 4 and EM 5 had coarser grain sizes. EM 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors, and EM 5 was primarily a river and lake sediment product modified by weathering. The sediment particle size results from the study area indicate that the sediment in the sandy region is generally coarse due to multiple factors, including topography, climate, hydrology, and human activity. Sandy material in the study area originated from nearby, with very little sand being transported from long distances. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Evolution of tectonic landscapes and deformation in the southeast Kumaun and western Nepal Himalaya.
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Luirei, Khayingshing, Kothyari, Girish Ch., Gautam, Param K., Solanki, Ambar, Patidar, Atul Kumar, Jamir, Sentisenla, Datta, Anirudh, and Choudhury, Tanupriya
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TECTONIC landforms ,SYNTHETIC aperture radar ,TERRACES (Geology) ,EARTHQUAKES ,LANDFORMS - Abstract
The area of the present investigation's expanse constitutes the southernmost extent of the southeast Kumaun Himalaya and western Nepal Himalaya. Multidisciplinary approaches have been employed to understand the landforms associated with tectonic deformation, through detailed field investigation supplemented by the geodetic, chronological, and morphometric database. The morphogenic expressions of the Main Boundary Thrust (MBT) are reflected in the form of ~25 km long E-W trending north dipping fault scarp. The deformation along the strike length of the Himalayan Frontal Thrust (HFT) is noticed in the form of uplifted and incised fill terraces, and strath terraces. The deformation within the fluvial sequences in the study area can be visualized in the form of sheared boulders and pebbles, tilted and faulted terrace deposits. Furthermore, the chronological data of fluvial landforms in the study area suggests two major phases of tectonic deformations that have occurred around 58.7±10.8 ka and 3.88±0.4 ka. The chronology of late-Quaternary landforms advocates that the initial stage of aggradations in the Himalayan foothills commenced around 75.1±0.58 ka. The aggradational landforms resulted from the diverse depositional regime as evident from the nature of the sediment sequences from clasts dominated to thick mud sequences. The rate of deformation in the southeastern Kumaun and western Nepal Himalaya is ± 7 mm/yr, as per the data obtained from the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR). The landform deformation pattern, phase of incision and aggradation, frequent occurrence of landslides, and recent past earthquake activity within the wide zone of the HFT, the MBT, and Ramgarh Thrust suggests that the southernmost front of the Kumaun Himalaya is active and has potential for future geohazard. The foothill zone of Himalayan towns are actively growing in terms of population and infrastructural development. Therefore, such intradisciplinary studies for tectonically active regions are needed for future infrastructural development. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Tidal dynamic response to riverbed evolution in the Yangtze River Estuary.
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Han, Yufang, Dai, Bingke, and Ding, Hongwei
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RIVER channels , *ESTUARIES , *LANDFORMS , *TIDE-waters , *ESTUARY management , *FLOOD control - Abstract
Since 1958, there have been significant changes in the Yangtze River estuary. Due to extensive reclamation and construction of ports and channels, the water area has drastically decreased, resulting in corresponding changes in hydrodynamics and riverbeds at the mouth of the river. According to the analysis of measured topographic data and Delft3D-FLOW model for seven typical historical periods since 1958 at the Yangtze River Estuary, this study investigates the characteristics of riverbed evolution and tidal flow dynamics. From 1958 to 2019, driven by strong human activities, the total area of the Yangtze River Estuary decreased from 2084 km2 to 1403 km2, with a decrease of 32.7%, while the total volume of the corresponding river channel changed slightly and remained stable. Compared with 1958, the volume of the Yangtze River Estuary in 2019 only increased by 345 million m3, with an increase of about 4.1%. The tidal dynamic change of the Yangtze Estuary is closely related to the riverbed evolution of each reach, which not only shapes the estuary landform, but also is affected by the riverbed evolution. Tidal level, tidal range and water area change are closely related. With the decrease of water area in the Yangtze River Estuary, tidal range tends to increase. Tidal prism change is closely related to channel volume. In the past 60 years, the tidal volume at the mouth of the Yangtze River has decreased by 8%. The research findings will provide technical support for enhancing flood control and tide resistance measures at the Yangtze River Estuary, as well as formulating comprehensive management plans for estuaries, contributing to the protection and sustainable development of the Yangtze River Estuary. [ABSTRACT FROM AUTHOR]
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- 2024
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15. The Feedback from a Beach Berm during Post-Storm Recovery and How to Improve the Berm's Restorative Efficiency.
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Zhu, Yu, Zhou, Yingtao, Zeng, Weite, Feng, Weibing, and Jiang, Yuanshu
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STORM surges ,LANDFORMS ,EROSION ,SEDIMENTS ,FORUMS ,BEACH erosion - Abstract
The efficiency of beach recovery during a time of moderate waves following storm waves is closely related to the interaction between dynamics, sediment, and the landform. The existing studies mainly focus on the description of erosion and accretion characteristics, while the response and feedback mechanism of beach berm sediment have not been elucidated. The main controlling factors of recovery efficiency are not clear. In this paper, field observation and the XBeach numerical model are utilized on the sandy beach in Puqian Bay, China, to capture high-frequency cross-shore data during the post-storm recovery period. The variation characteristics and rules of berm elements, including berm ridge height and slope on two sides of the berm ridge, are analyzed. It is observed that the berm constantly changes to adapt to dynamic conditions. Additionally, a correlation between volume change and certain landform parameters is proposed, leading to the identification of a new relationship in wave run-up. The new forum reflects berm influence and considers the berm ridge and berm width. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Macro- and micro-anatomical investigation of the oropharyngeal roof of landform greek tortoise (Testudo graeca graeca) and semi-aquatic red-eared slider turtle (Trachemys scripta elegans).
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Alsafy, Mohamed A.M., El-Sharnobey, Nermin K.A., El-Gendy, Samir A.A., Abumandour, Mohamed A., Elarab, Samar M. Ez, and Hanafy, Basma G.
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LANDFORMS , *ALVEOLAR process , *TESTUDINIDAE , *TURTLES , *MASTICATION , *MICROSCOPES - Abstract
The present investigation examined the oropharyngeal roof of two turtles having different feeding behaviors: the landform Greek tortoise (Testudo graeca graeca) primarily herbivores and the semi-aquatic red-eared slider turtle (Trachemys scripta elegans) lives in freshwater that opportunistic omnivorous grossly and by scanning and light microscopes. Grossly, the Greek tortoise had a V-shaped roof consisting of the upper rhamphotheca, peri-palatine region, upper alveolar ridge, peripheral palatine ridge, median palatine ridge, vomer, choanae, caudal palatine part, and pharynx. At the same time, the red-eared slider had a semilunar roof consisting of upper rhamphotheca, two peripheral palatine ridges, core of palatine ridges, upper alveolar band, vomer, choanae, caudal palatine part, and pharynx. SEM revealed that the red-eared slider roof appeared more straightforward. The upper rhamphotheca is sharp, with a median premaxillary notch in the red-eared slider that gives a powerful bite for cutting to compensate absence of the teeth. Additionally, the red-eared slider's upper alveolar band is interrupted by a single upper alveolar ridge that appears spiky, pointed, and longer as it needs powerful chewing of prey and there are two types of teeth-like projections at its peri-palatine area for food-crushing and chewing. The Greek tortoise palatine region had numerous ridges and folds to provide roughness for food processing. Greek tortoises had small-sized choanae with two choanal folds to minimize choanal openings when eating dusty grasses. Histologically, Greek tortoise palate was rostrally thicker and more keratinized than caudally, and the caudal palatine region was characterized by a single pair of circumvallate-like papilla with multiple mucous openings and secretions, while red-eared slider palate was slightly keratinized at the peri-choanal region, and the rest of the palate was non-keratinized with few mucous openings. The current investigation found various structural oropharyngeal roof adaptations to feeding behavior in the omnivore red-eared slide compared to the herbivorous Greek turtle. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Digital Geomorphological Mapping of Sabkhas in the Western Gulf of Suez, Egypt.
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Mohamed, Mohamed El-Raei
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GEOMORPHOLOGICAL mapping , *GEOGRAPHIC boundaries , *LANDFORMS , *REMOTE-sensing images - Published
- 2024
18. Analyzing the sensitivity of a blowing snow model (SnowPappus) to precipitation forcing, blowing snow, and spatial resolution.
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Haddjeri, Ange, Baron, Matthieu, Lafaysse, Matthieu, Le Toumelin, Louis, Deschamps-Berger, César, Vionnet, Vincent, Gascoin, Simon, Vernay, Matthieu, and Dumont, Marie
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REMOTE-sensing images , *LANDSAT satellites , *LANDFORMS , *WIND pressure , *SPATIAL resolution , *SNOW cover - Abstract
Accurate snow cover modeling is a high-stakes issue for mountain regions. Alpine snow evolution and spatial variability result from a multitude of complex processes including interactions between wind and snow. The SnowPappus blowing snow model was designed to add blowing snow modeling capabilities to the SURFEX/Crocus simulation system for applications across large spatial and temporal extents. This paper presents the first spatialized evaluation of this simulation system over a 902 km 2 domain in the French Alps. Here we compare snow cover simulations to the spatial distribution of snow height obtained from Pléiades satellites stereo imagery and to snow melt-out dates from Sentinel-2 and Landsat 8 time series over three snow seasons. We analyzed the sensitivity of the simulations to three different precipitation datasets and two horizontal resolutions. The evaluations are presented as a function of elevation and landform types. The results show that the SnowPappus model forced with high-resolution wind fields enhances the snow cover spatial variability at high elevations allowing a better agreement between observed and simulated spatial distributions above 2500 m and near peaks and ridges. Model improvements are not obvious at low to medium altitudes where precipitation errors are the prevailing uncertainty. Our study illustrates the necessity to consider error contributions from blowing snow, precipitation forcings, and unresolved subgrid variability for robust evaluations of spatialized snow simulations. Despite the significant effect of the unresolved spatial scales of snow transport, 250 m horizontal-resolution snow simulations using SnowPappus are found to be a promising avenue for large-scale modeling of alpine snowpacks. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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19. Distribution, habitat associations and status of the Carpentarian Pseudantechinus (Pseudantechinus mimulus, Dasyuridae).
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Barnes, Jarrad C., Clemente, Christofer J., Brunton, Elizabeth A., Sanders, Mark G., and Burnett, Scott E.
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ENDANGERED species , *HABITATS , *SPECIES distribution , *DATABASES , *LANDFORMS - Abstract
The Carpentarian Pseudantechinus (Pseudantechinus mimulus, Dasyuridae) is a little‐known, saxicolous dasyurid marsupial from the Mount Isa Inlier bioregion in Queensland (QLD) and the Gulf Coastal bioregion in the Northern Territory (NT), Australia. A paucity of targeted survey effort across broad swathes of potentially suitable habitat means that the species' distribution and habitat associations are uncertain. This study aimed to (1) refine the contemporary distribution of P. mimulus, (2) determine the landscape and floristic variables that may predict P. mimulus presence, and (3) assess the current conservation status of P. mimulus. We conducted camera trap surveys covering 631 camera stations at 227 independent sites over 4 years for a total of 28 767 trap‐nights throughout QLD and NT in known and predicted suitable habitat. Stepwise generalized linear models were used to test the effect of landscape and floristic predictors on P. mimulus presence. The species' contemporary distribution was assessed using a MAXENT species distribution model. We collated a database of 292 records of P. mimulus, including 111 recorded during this study, extending the species' known range in QLD. The proposed holotype location of the Mittiebah Range was surveyed twice during this study but P. mimulus was not recorded. Pseudantechinus mimulus had the highest probability of presence on most non‐northerly aspects on metamorphic landforms. Eleven plant taxa had a significant effect on P. mimulus presence. This study provides new evidence for landscape and floristic factors that help predict the presence of P. mimulus. Our results indicate the possibility of two disjunct populations, but large swathes of potential habitat still require additional effort to determine the species' true distribution. Our estimate for area of occupancy partially satisfies a threatened species listing; however, more focused research on population dynamics, trends in habitat quality, and landscape‐scale threats is necessary. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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20. Younger Dryas and Early Holocene ice‐margin dynamics in northwest Russia.
- Author
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Boyes, Benjamin M., Pearce, Danni M., Linch, Lorna D., and Nash, David J.
- Subjects
- *
YOUNGER Dryas , *HOLOCENE Epoch , *ICE sheets , *LANDFORMS , *CLIMATE change , *MELTWATER , *SUBGLACIAL lakes - Abstract
The dynamics of the last Fennoscandian Ice Sheet (FIS) are relatively well constrained in the Nordic countries. Ice‐sheet dynamics in NW Russia, however, are comparatively less well understood owing to the scale and resolution of existing studies. New large‐scale glacial geomorphological datasets from NW Russia based on high‐resolution remotely sensed imagery allow for an independent reassessment of the extent and dynamics of the FIS during the Younger Dryas and Early Holocene (c. 12.9–10 ka) in NW Russia. The reconstruction provides a more detailed link between geomorphological expressions of palaeoglaciation than previous proposals. Rather than a continuous Younger Dryas ice marginal zone (IMZ) stretching from Finland to northern Norway, the geomorphological signature of NW Russia reveals 14 IMZs that document discrete stationary ice‐margin positions (possibly standstill and/or readvance events) during the overall retreat. The relative age sequence of the IMZs, supported by an updated numerical age database, suggests that they formed time‐transgressively during the Younger Dryas and Early Holocene rather than contemporaneously. Moreover, specific landform assemblages reveal contrasting glacial landsystems in NW Russia: (i) a northern subpolar glacial landsystem; and (ii) a southern temperate glacial landsystem. The model presented herein provides robust empirical constraints for testing and validating numerical ice‐sheet models and understanding ice‐sheet responses to rapid climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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21. Okanogan lobe tunnel channels and subglacial floods into Moses Coulee, Channeled Scabland, northwestern United States.
- Author
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Gombiner, Joel and Lesemann, Jerome-Etienne
- Subjects
- *
FLOOD routing , *GLACIAL lakes , *FLOODS , *SUBMARINE fans , *LANDFORMS , *MORAINES - Abstract
Outburst floods from glacial Lake Missoula largely explain erosion of the Channeled Scabland, a system of overfit, basaltic channels in Washington, northwestern United States. However, it is challenging to explain Missoula flood routing into Moses Coulee due to its topographic isolation from flood routes. To clarify flood pathways into Moses Coulee, we mapped channels that delineate a radial-anastomosing network connecting to Moses Coulee. Channels consist of coulee-like features eroded mainly in basalt. Channels climb adverse slopes and cross divides, and the network is draped with eskers and recessional moraines. These channel geometries and glacial landform associations suggest a tunnel channel network. Large channel dimensions and network anastomosis indicate formation in subglacial floods. The network connects to Moses Coulee with sufficient cross-sectional area to convey megafloods, hinting that subglacial floods may have been a significant source of Moses Coulee meltwater, in addition to possible diverted Missoula floods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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22. Relative improvements between roads and railways and economic performance: A panel data analysis.
- Author
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Zheng, Qing Yuan, Law, Teik Hua, Wong, Shaw Voon, and Ng, Choy Peng
- Subjects
- *
ECONOMIC indicators , *INFRASTRUCTURE (Economics) , *LOCAL transit access , *DATA analysis , *LANDFORMS , *ECONOMIC expansion - Abstract
Prior studies indicate that expanding the length of roadways and railways has a beneficial effect on economic performance. Nevertheless, the requirement for land transport infrastructure, which offers different degrees of accessibility and mobility, to facilitate economic expansion differs based on a country's stage of development. The present study has two objectives. Firstly, it is essential to ascertain the required investment for different types of land transport infrastructure to facilitate different stages of economic performance. Secondly, the objective is to examine the impact of different forms of land transportation infrastructure on economic performance by means of urbanization and exports. To highlight these concerns, a fixed-effects panel linear regression analysis was conducted on a panel consisting of 50 countries spanning the years 1980–2018. In countries with lower levels of urbanization and exports, improvements to road infrastructure, especially roads with high accessibility, are of greater importance for economic performance compared to the improvement of railways. Nevertheless, as urbanization and exports rise, the comparative impact of improvements in road infrastructure on economic performance in relation to improvements in railway infrastructure diminishes. Railway improvements have a more significant effect on economic performance compared to road improvements, owing to increased urbanization and export rates. During these stages of development, high-mobility roads are more crucial for economic performance compared to high-accessibility roads. The conclusion of the research examined a variety of policy recommendations derived from our findings, which are applicable to different levels of urbanization and exports. • Evaluate the economic benefits of various land transportation infrastructure. • Assess the capital needed for various transport infrastructure to help the economy. • Low urbanization and export require high-access roads to boost economy. • High urbanization and export require railways to boost economy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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23. Geoforms and Biogeography Defining Mangrove Primary Productivity: A Meta-Analysis for the American Pacific.
- Author
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Velázquez-Pérez, Carolina, Romero-Berny, Emilio I., Miceli-Méndez, Clara Luz, Moreno-Casasola, Patricia, and López, Sergio
- Subjects
IMAGE analysis ,REMOTE-sensing images ,LANDFORMS ,CLIMATE change ,MANGROVE plants ,MANGROVE forests - Abstract
We present a meta-analysis of mangrove litterfall across 58 sites in the American Pacific, exploring its variability among geoforms, ecoregions, and provinces. This study contributes to filling the information gap on litter-based primary productivity in American mangroves at the ecoregional level and directly examines the effects of geomorphological and biogeographic factors on mangrove productivity. The objective was to evaluate how geoform, ecoregion, and province factors, along with eight environmental variables, influence litterfall-based primary productivity. Each site was categorized according to its landform through the analysis of satellite images obtained from various sensors on the Google Earth Pro v. 7.3.6 platform. Additionally, it was categorized according to its ecoregion and province by analyzing the occurrence of the sites on biogeographic unit coverage in ArcMap 10.4.1. We then analyzed the effect of each factor and the efficiency of categorization using multivariate methods. Our results showed significant differences in litterfall among the geoforms, with estuaries exhibiting higher litterfall production (11.90 Mg ha
−1 year−1 ) compared to lagoons (7.49 ± 4.13 Mg ha−1 year−1 ). Differences were also observed among provinces, with the highest average in the Tropical Eastern Pacific (11.19 ± 3.63 Mg ha−1 year−1 ) and the lowest in the Warm Temperate Northeast Pacific (7.34 ± 4.28 Mg ha−1 year−1 ). Allocation success analyses indicated that sites classified by dominant species and province were more predictable (>60.34%) for litterfall production. Additionally, the maximum temperature and the precipitation of the wettest month and the driest month explained 34.13% of the variability in mangrove litter-based primary productivity. We conclude that mangrove litterfall production is influenced by coastal geomorphic characteristics and biogeography, which are, in turn, affected by latitude-induced climate variation. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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24. Spatiotemporal Variations in Co-Occurrence Patterns of Planktonic Prokaryotic Microorganisms along the Yangtze River.
- Author
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Du, Wenran, Li, Jiacheng, Zhang, Guohua, Yu, Ke, and Liu, Shufeng
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MOLECULAR biology ,COEXISTENCE of species ,BIOGEOCHEMICAL cycles ,FRESHWATER ecology ,ECOSYSTEM dynamics - Abstract
Bacteria and archaea are foundational life forms on Earth and play crucial roles in the development of our planet's biological hierarchy. Their interactions influence various aspects of life, including eukaryotic cell biology, molecular biology, and ecological dynamics. However, the coexistence network patterns of these microorganisms within natural river ecosystems, vital for nutrient cycling and environmental health, are not well understood. To address this knowledge gap, we systematically explored the non-random coexistence patterns of planktonic bacteria and archaea in the 6000-km stretch of the Yangtze River by using high-throughput sequencing technology. By analyzing the O/R ratio, representing the divergence between observed (O%) and random (R%) co-existence incidences, and the module composition, we found a preference of both bacteria and archaea for intradomain associations over interdomain associations. Seasons notably influenced the co-existence of bacteria and archaea, and archaea played a more crucial role in spring as evidenced by their predominant presence of interphyla co-existence and more species as keystone ones. The autumn network was characterized by a higher node or edge number, greater graph density, node degree, degree centralization, and nearest neighbor degree, indicating a more complex and interconnected structure. Landforms markedly affected microbial associations, with more complex networks and more core species found in plain and non-source areas. Distance-decay analysis suggested the importance of geographical distance in shaping bacteria and archaea co-existence patterns (more pronounced in spring). Natural, nutrient, and metal factors, including water temperature, NH
4 + -N, Fe, Al, and Ni were identified as crucial determinants shaping the co-occurrence patterns. Overall, these findings revealed the dynamics of prokaryotic taxa coexistence patterns in response to varying environmental conditions and further contributed to a broader understanding of microbial ecology in freshwater biogeochemical cycling. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
25. Landslide Distribution and Development Characteristics in the Beiluo River Basin.
- Author
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Liu, Fan, Deng, Yahong, Zhang, Tianyu, Qian, Faqiao, Yang, Nan, Teng, Hongquan, Shi, Wei, and Han, Xue
- Subjects
LANDSLIDES ,LANDFORMS ,LANDSLIDE hazard analysis ,WATERSHEDS ,GEOLOGICAL maps ,REMOTE-sensing images - Abstract
The Beiluo River Basin, situated in the central region of the Loess Plateau, frequently experiences landslide geological disasters, posing a severe threat to local lives and property. Thus, establishing a detailed database of historical landslides and analyzing and revealing their development characteristics are of paramount importance for providing a foundation for geological hazard risk assessment. First, in this study, landslides in the Beiluo River Basin are interpreted using Google Earth and ZY-3 high-resolution satellite imagery. Combined with a historical landslide inventory and field investigations, a landslide database for the Beiluo River Basin is compiled, containing a total of 1781 landslides. Based on this, the geometric and spatial characteristics of the landslides are analyzed, and the relationships between the different types of landslides and landslide scale, stream order, and geomorphological types are further explored. The results show that 50.05% of the landslides have a slope aspect between 225° and 360°, 68.78% have a slope gradient of 16–25°, and 38.97% are primarily linear in profile morphology. Areas with a high landslide density within a 10 km radius are mainly concentrated in the loess ridge and hillock landform region between Wuqi and Zhidan Counties and in the loess tableland region between Fu and Luochuan Counties, with a significant clustering effect observed in the Fu County area. Loess–bedrock interface landslides are relatively numerous in the northern loess ridge and hillock landform region due to riverbed incision and the smaller thickness of loess in this area. Intra-loess landslides are primarily found in the southern loess tableland region due to headward erosion and the greater thickness of loess in this area. Loess–clay interface landslides, influenced by riverbed incision and the limited exposure of red clay, are mainly distributed in the northern part of the southern loess tableland region and on both sides of the Beiluo River Valley in Ganquan County. These results will aid in further understanding the development and spatial distribution of landslides in the Beiluo River Basin and provide crucial support for subsequent landslide susceptibility mapping and geological hazard assessment in the region. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Spring erosional processes and small sapping valleys in southwestern lower Michigan, USA.
- Author
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Colgan, Patrick M., Larson, Eleanore A., Riemersma, Peter E., Szydlowski, Hanna V., and Baker, Tyler
- Subjects
VALLEYS ,WATER temperature ,LANDFORMS ,WATER table ,BED load ,GRAIN size - Abstract
Tributary valleys along the Pigeon River in southwestern Michigan USA possess many previously defined criteria for sapping valleys. Direct observations of seasonal variations in groundwater levels, hydraulic gradients and water temperatures confirm that perennial springs and their streams are present in these small valleys. Estimated spring‐fed stream discharges are low and variable, but continuous. Direct observations, grain‐size distributions and bedload transport estimates indicate that significant transport of fine to medium sand occurs in all seasons. We present a process‐form model for small‐scale sapping processes. Stream terraces and paleo‐meander scarps are being modified by sapping, and elongated valleys are likely being lengthened headward by groundwater sapping. Sapping processes have been occurring for at least the past ~4,500 years after Pigeon River adjusted to a fall in base level from the Nipissing high stand to the modern level of Lake Michigan. Sapping processes are currently producing a variety of small‐scale landforms dependent on four main factors: 1) hydraulic gradients and spring discharges, 2) available grain size of material being eroded, 3) transport rate of sand bedload by spring‐fed streams and finally 4) time available for groundwater sapping process to occur. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Sustainable Agriculture as Influenced by Landform in Qena Governorate, Egypt.
- Author
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Elsaid Saeed, Mohamed Ahmed, El-Desoky, Ahmed Ibrahim, and Sayed, Yasser Abdel-Aal
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SUSTAINABLE agriculture ,LANDFORMS ,NATURAL resources ,TERRACES (Geology) ,SOCIAL acceptance - Abstract
Ensuring sustainability of agricultural is imperative for Egypt's modest national income, with a focus on improving land production and conserving natural resources. The urgency arises due to population growth and new land reclamation, posing sustainability challenges such as soil characteristics, alkalinity, salinity limitations, socio-economic factors, and environmental hazards. This study evaluates the sustainability of agricultural status of some soils in Qena Governorate, integrating biophysical, economic viability, and social acceptability aspects, and examining their correlation with landform types. The sustainability framework encompasses five factors: productivity, security, protection, economic viability, and social acceptability. The productivity index ranges from 0.29 to 0.43, protection factors exhibit values from 0.49 to 0.90, security factors range between 0.56 and 0.90, economic viability index spans from 0.45 to 0.80, and social acceptability varies from 0.47 to 1.00. The study classifies the investigated area into two classes (S3 and S4) based on the sustainable agricultural framework. The region faces challenges in local infrastructure, health facilities, and education. The results underscore a distinct correlation between sustainability indices and geomorphological units, with the Plain Valley consistently displaying the highest values, followed by the Low River terraces, Moderate River terraces, and High River terraces, while the Overflow basin consistently exhibits the lowest values. The findings emphasize that decision-makers can enhance land sustainability in the study area by focusing on two key factors: social and economic considerations, while also accounting for the impact of landform. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Towards biogeomorphic river restoration: Vegetation as a critical driver of physical habitat.
- Author
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O'Briain, Rossa, Corenblit, Dov, Garófano‐Gómez, Virginia, and O'Leary, Ciara
- Subjects
RIPARIAN plants ,STREAM restoration ,HABITATS ,WATERSHEDS ,STREAMFLOW ,LANDFORMS ,PLANT communities - Abstract
The current focus of river restoration on flow and sediment transfer without proper consideration of vegetation as a key structuring agent, beyond its stabilising effect, is too simplistic. We contend that vegetation has an essential role in shaping the physical fluvial environment and should be considered equally alongside hydrogeomorphic processes in restoration projects. In support, we introduce engineer plants as important controls, along with flowing water and transported sediments, on the morphodynamics of river systems and associated physical habitat development. The effect of vegetation on channel planform is then summarised, the influence of vegetation on hydrogeomorphic connectivity is outlined, and then the role of vegetation in landform development and habitat provision, as encapsulated in the fluvial biogeomorphic succession model, is described. We then present examples demonstrating how vegetation has contributed to the recovery of degraded rivers through biogeomorphic processes. Finally, we advance the concept of biogeomorphic river restoration by proposing principles to support a closer synthesis of the component sciences and list key areas for practitioners to focus on. Vegetation succession has a significance that goes beyond its physical structure or influence on sediment stability. In many river settings, it is central to channel evolution. The coupled assembly of plant communities and fluvial landforms affect the development of spatially and temporally dynamic habitat through biogeomorphic interactions. Restoration approaches that do not fully consider this dynamic may fail to anticipate river behaviour and recovery trajectories. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Illicit crops in the frontier margins: Amazonian indigenous livelihoods and the expansion of coca in Peru.
- Author
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Paredes, Maritza and Pastor, Alvaro
- Subjects
INDIGENOUS peoples of South America ,RISK of violence ,LANDFORMS ,POWER (Social sciences) ,CROPS ,FOOD security ,SOCIOHISTORICAL analysis - Abstract
This paper explores illegal coca crop expansion in indigenous Amazonian communities in Peru. The ethnographic study sheds light on the historical development of these areas as frontier spaces, where the growth of illicit crops intertwines with socio-ecological transformations and gives rise to conflicts over new forms of land control, opportunities for capital accumulation, and political power dynamics. The paper argues that this expansion is shaped by dual processes: from 'below,' involving small-scale migrant farmers from the Andes, and from 'above,' primarily driven by state-led agrarian interventions. Consequently, communities experience significant tensions, as they adapt to the forces of market expansion to secure their livelihoods, while simultaneously facing risks of violence and insecurity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. The applicability of automated marine clay gully delineation using deep learning in Norway.
- Author
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Ganerød, Alexandra Jarna, van Boeckel, Mikis, and Solberg, Inger‐Lise
- Subjects
DEEP learning ,CLAY ,CONVOLUTIONAL neural networks ,MARINE sediments ,GEOMORPHOLOGICAL mapping ,SOIL erosion - Abstract
Gullies and ravines are common landforms in raised marine fine‐grained deposits in Norway. Gullies in marine clay are significant landforms indicative of soil erosion and natural hazards and are of high conservation value. As a result of the substantial impact of human intervention over the past century, marine clay gullies are now red‐listed. To monitor the condition of these landforms, we need to improve our understanding of their spatial extent, complexity and morphology. We explore the applicability of automated approaches that use a methodology of combining deep learning (DL), fully convolutional neural networks (FCNNs) and an unmodified U‐Net model with ArcPy libraries and ground truth data to derive a high‐resolution map of gullies in raised marine fine‐grained deposits. Predictors used comprise solely terrain derivatives to broaden the usage of the pre‐trained model to other regions. Our best model achieved a precision score of 0.82 and a recall of 0.75. We find that our pre‐trained model can successfully predict gullies, also in blind‐test areas. The model performs better in regions with similar geological settings, scoring a length‐weighted overlap of >70% with reference datasets. The novelty of this study is that we demonstrate that the model's applicability for mapping routines increases when we post‐process the predictions by eliminating noise, especially by using the predictions derived from ensembled models. We, therefore, conclude that the pre‐trained models can effectively be used to supplement the geomorphological mapping of marine clay gullies in Norway. The outcome of this research contributes towards mapping the spatial extent and condition of red‐listed landforms in Norway, as well as the development of monitoring systems for future landscape change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Landform and lithospheric development contribute to the assembly of mountain floras in China.
- Author
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Zhao, Wan-Yi, Liu, Zhong-Cheng, Shi, Shi, Li, Jie-Lan, Xu, Ke-Wang, Huang, Kang-You, Chen, Zhi-Hui, Wang, Ya-Rong, Huang, Cui-Ying, Wang, Yan, Chen, Jing-Rui, Sun, Xian-Ling, Liang, Wen-Xing, Guo, Wei, Wang, Long-Yuan, Meng, Kai-Kai, Li, Xu-Jie, Yin, Qian-Yi, Zhou, Ren-Chao, and Wang, Zhao-Dong
- Subjects
MOUNTAIN plants ,BEDROCK ,SPECIES diversity ,MOUNTAINS ,BOTANY ,LANDFORMS - Abstract
Although it is well documented that mountains tend to exhibit high biodiversity, how geological processes affect the assemblage of montane floras is a matter of ongoing research. Here, we explore landform-specific differences among montane floras based on a dataset comprising 17,576 angiosperm species representing 140 Chinese mountain floras, which we define as the collection of all angiosperm species growing on a specific mountain. Our results show that igneous bedrock (granitic and karst-granitic landforms) is correlated with higher species richness and phylogenetic overdispersion, while the opposite is true for sedimentary bedrock (karst, Danxia, and desert landforms), which is correlated with phylogenetic clustering. Furthermore, we show that landform type was the primary determinant of the assembly of evolutionarily older species within floras, while climate was a greater determinant for younger species. Our study indicates that landform type not only affects montane species richness, but also contributes to the composition of montane floras. To explain the assembly and differentiation of mountain floras, we propose the 'floristic geo-lithology hypothesis', which highlights the role of bedrock and landform processes in montane floristic assembly and provides insights for future research on speciation, migration, and biodiversity in montane regions. An analysis of 140 floras from China reveals that high species diversity exists in granite and mixed landforms, while low species diversity is found in karst, Danxia, and desert landforms. Based on these findings, the authors provide new clues for understanding the assembly and differentiation of mountain floras, highlighting the role of bedrock and landform processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Detection of terrain feature points from digital elevation models using contour context.
- Author
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Jiapei Hu, Xuejun Liu, and Bo Wu
- Subjects
- *
DIGITAL elevation models , *RELIEF models , *LANDFORMS , *MATHEMATICAL models , *SPACE-based radar - Abstract
Terrain feature points, such as peaks, pits, and saddles, represent the macro-structure of the landform. Conventional techniques for extracting these points from digital elevation models (DEMs) often grapple with issues of inaccuracy, omission and redundancy, largely due to the problematic necessity of setting threshold values. This paper proposes an innovative approach for the automatic detection of terrain feature points based on the topological relationships of contours and the inherent constraints of terrain shape characteristics. The study provides a robust mathematical model of terrain feature points and an effective algorithm for their extraction. Comparing with manually reference data, the accuracy metrics including completeness, correctness, and quality of our extracted results demonstrate a high level, significantly surpassing those obtained through existing algorithms. This proposed approach not only avoids the spurious feature points produced by the local window method, but also prevents the omission of valid points and the creation of redundant ones. Moreover, by utilizing the contour interval as its only variable, our approach eliminates the need for various threshold settings, streamlining the extraction process. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. A Type of Scale-Oriented Terrain Pattern Derived from Normalized Topographic Relief Layers and Its Interpretation.
- Author
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Nan, Xi, Li, Ainong, He, Zhengwei, and Bian, Jinhu
- Subjects
- *
LANDFORMS , *TOPOGRAPHY , *COLOR - Abstract
Topographic scale characteristics contain valuable information for interpreting landform structures, which is crucial for understanding the spatial differentiation of landforms across large areas. However, the absence of parameters that specifically describe the topographic scale characteristics hinders the quantitative representation of regional topography from the perspective of spatial scales. In this study, false-color composite images were generated using normalized topographic relief data, showing a type of scale-oriented terrain pattern. Subsequent analysis indicated a direct correlation between the luminance of the patterns and the normalized topographic relief. Additionally, a linear correlation exists between the color of the patterns and the change rate in normalized topographic relief. Based on the analysis results, the issue of characterizing topographic scale effects was transformed into a problem of interpreting terrain patterns. The introduction of two parameters, flux and curl of topographic field, allowed for the interpretation of the terrain patterns. The assessment indicated that the calculated values of topographic field flux are equivalent to the luminance of the terrain patterns and the variations in the topographic field curl correspond with the spatial differentiation of colors in the terrain patterns. This study introduced a new approach to analyzing topographic scale characteristics, providing a pathway for quantitatively describing scale effects and automatically classifying landforms at a regional scale. Through exploratory analysis on artificially constructed simple DEMs and verification in four typical geomorphological regions of real terrain, it was shown that the terrain pattern method has better intuitiveness than the scale signature approach. It can reflect the scale characteristics of terrain in continuous space. Compared to the MTPCC image, the terrain parameters derived from the terrain pattern method further quantitatively describe the scale effects of the terrain. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Dipping Tidal Notch (DTN): Exposed vs. Sheltered Morphometry.
- Author
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Furlani, Stefano, Agate, Mauro, de Sabata, Eleonora, Chemello, Renato, Vaccher, Valeria, Visconti, Giulia, and Antonioli, Fabrizio
- Subjects
- *
SEA level , *COASTS , *LANDFORMS , *PETROLOGY , *EROSION , *ARCHIPELAGOES , *MORPHOMETRICS - Abstract
Tidal notches, long regarded as reliable indicators of mean sea level, have been extensively studied along carbonate coasts in the central Mediterranean Sea. Previous studies revealed a correlation between the genesis of tidal notches and tidal range, lithology, cliff foot depth, and wave energy. In the 2020 Geoswim campaigns at Lampedusa, the southernmost island of the Pelagie archipelago (Italy), and in Gozo Island (Malta), 'anomalous' tidal notches were identified. Unlike normal notches observed elsewhere, those in Lampedusa's southern bays exhibited a particular behaviour—constantly deepening in the inner part of the bays, reaching a maximum depth of approximately 30 cm below sea level and narrowing inwards. Similar phenomena were previously observed near Marseille (France). As confirmed by the literature, all these areas are tectonically stable. Time-lapse images, alongside measurements of morphometric parameters, were collected during the survey. Our hypothesis indicates that a combination of marine factors influenced by local marine conditions driven by the local morphology of the small bays exposed to southern quadrants contribute to the formation of these unique landforms. The latter manifests higher lowering erosion rates slightly below the mean sea level in sheltered areas, challenging conventional notions about tidal notch formation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Geosites and Climate Change—A Review and Conceptual Framework.
- Author
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Migoń, Piotr
- Subjects
- *
EXTREME weather , *CONSCIOUSNESS raising , *ROCK properties , *LANDFORMS , *SOUND recordings - Abstract
Geosites are windows into the geological past, which may be recorded in rocks and their properties, the fossil content, and landform produced by processes no longer operating. Since the histories of sedimentation, life, and landscape evolution are to a certain extent controlled by climatic conditions, some geosites may be used as illustrations of various themes linked to the issue of climate change. In this paper, a coherent systematic framework is proposed for how to look at geosites through the lens of climate change. Four major aspects of relevance are recognized: (i) geosites providing evidence of changing climatic conditions in the past; (ii) geosites providing evidence of an environment different than that of today at the place; (iii) geosites providing evidence of extreme weather events; and (iv) dynamic geosites, subject to change as a response to ongoing climate change. The use of geosites to raise awareness and educate the public about climate change faces various interpretation challenges. In particular, linking with ongoing climate change requires caution and balanced presentation as most geosites record changes which occurred without any anthropogenic component. The preferred focus should be on environmental instability in general rather than on any specific reasons for change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Quantifying the spatial associations among terrain parameters from digital elevation models.
- Author
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Zhong, Yutao, Xiong, Liyang, Zhou, Yumeng, and Tang, Guoan
- Subjects
- *
DIGITAL elevation models , *CELL size , *LANDFORMS - Abstract
Terrain parameters describe the morphological characteristics of a surface and are an important part of the application of geoscience. At present, there is still a lack of scientific and systematic research on the associations among terrain parameters. In this article, 14 representative terrain parameters are selected to explore their spatial association relationships by using the quantification methods of linear correlation degree, distribution similarity and influence degree. Then, we discuss the effects of the digital elevation model (DEM) cell size and landform region on the associations among terrain parameters. Furthermore, the mechanism of the association relationships among terrain parameters is also analyzed to achieve a better understanding of terrain analysis. This study revealed that the similarity in calculation methods, the derivation of terrain parameters from other parameters, the geographic significance of representations, and the characteristics and appearances of landforms are significant factors contributing to the associations of terrain parameters. The terrain parameters with strong associations remained stable with changes in cell size and landform region. However, terrain parameters with weak associations significantly respond to this variety of factors. We quantify the associations among terrain parameters, provide a new perspective for examining the associations among terrain parameters, and provide guidance for the selection of terrain parameters in geoscience research. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Reconstructing of historical land cover based on contemporary cartographical materials.
- Author
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Sobala, Michał
- Subjects
- *
LAND cover , *HISTORICAL maps , *LANDFORMS , *LAND use , *CLIMATE change , *INFORMATION resources - Abstract
Historical land use reconstructions help to assess climate change, interactions between ecosystems and human and strengthen the knowledge about these interactions. They are conducted on the basis of historical maps that only cover certain areas. Hence, there is a need to seek other maps enabling historical land use to be reconstructed. The aim of study is to assess the suitability of contemporary maps for reconstructing a historical non-forest area range in the Western Carpathians. The content of contemporary maps was compared with that of historical maps, including the number of glades, their area and the length of their boundaries. Over 60% of glades were reconstructed, which is 90% of the glade area inventoried based on historical maps. Over 50% glades with an area of less than 1ha were not reconstructed. However, the area they occupy does not account for 2% of the total glade area. Thus, it has no significant impact on the total area of the reconstructed glades. As much as 90% of the boundaries' length was reconstructed. The study shows that contemporary maps may be useful in reconstructing the forest and glades range and may be an additional source of information to verify the content of historical maps. • Contemporary maps are useful to reconstruct the historical land cover. • Reconstructing the land cover forms area gives better results than their boundaries. • Invariability of the plot structure make it easier to reconstruct past land use. • Large land fragmentation make it easier to reconstruct past land use. • Spatial range of different plots indicates the maximal range of past deforestation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Multiple Uplift and Exhumation of the Southeastern Tibetan Plateau: Evidence from Low‐Temperature Thermochronology.
- Author
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WU, Limin, PENG, Touping, FAN, Weiming, ZHAO, Guochun, GAO, Jianfeng, DONG, Xiaohan, PENG, Shili, MIN, Kang, and MYINT, Tin Aung
- Subjects
- *
FISSION track dating , *ATMOSPHERIC carbon dioxide , *WEATHERING , *LANDFORMS , *BATHOLITHS - Abstract
Since the Cenozoic, the Tibetan Plateau has experienced large‐scale uplift and outgrowth due to the India–Asia collision. However, the mechanism and timing of these tectonic processes still remain debated. Here, using apatite fission track dating and inverse thermal modeling, we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau. In contrast to previous views, we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites, indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times. In addition, we also suggest that the 5–2 Ma mantle‐related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau, because it led to the increase in atmospheric CO2 level and a hotter upper crust than before, which are efficient for suddenly fast rock weathering and erosion. Finally, we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. A small landslide induced a large disaster prior to the heavy rainy season in Jinkouhe, Sichuan, China: characteristics, mechanism, and lessons.
- Author
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Hou, Runing, Li, Zhi, Ye, Weihao, Peng, Taixin, Tian, Shufeng, Chen, Ningsheng, Huang, Na, and Somos-Valenzuela, Marcelo
- Subjects
- *
LANDSLIDES , *WATER table , *WATER harvesting , *LANDFORMS , *GROUNDWATER flow , *NUMERICAL calculations - Abstract
Small-scale landslides that occur at unexpected locations and seasons can cause severe losses of life and property. Unusually, the Shidang landslide occurred prior to the rainy season in Jinkouhe County, Sichuan Province, China, resulting in 19 deaths and missing persons. In this paper, landslide characteristics and causes are revealed through a field investigation, laboratory experiments, and numerical calculations. The results show that the Shidang landslide was a small-scale landslide with a total volume of approximately 19500 m3, originating from hollow colluvial deposits. The geomorphological hollow above the landslide provided topographic conditions for the collection of subsurface runoff. Groundwater flow was transported downward along dolomite and accumulated in the area above shale, with a low conductivity. Groundwater table rise combined with the decrease in the soil strength led to landslide occurrence. Improper siting of residential areas and insufficient vigilance against post-rainfall landslides caused this tragedy. Considering the post-disaster lessons, it is strongly recommended that in the future, more attention should be given to the investigation of landslides triggered by groundwater, especially in determining landslide hydrological system boundaries. In mountainous areas where the developable space is limited, areas with hollow landforms are potentially at risk of geohazards. This paper could provide a reference for the prevention and management of similar landslides and new insights for updating landslide investigation systems and residential housing plans. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Numerical simulation analysis of wind field above pavement surface in different landforms by computational fluid dynamics approach.
- Author
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Jian Ouyang, Zhao Jiang, Leiyu Ye, Jing Li, and Peng Cao
- Subjects
PAVEMENTS ,COMPUTATIONAL fluid dynamics ,GEOGRAPHIC information systems ,WIND speed ,LANDFORMS - Abstract
The temperature and moisture of the pavement structure can be greatly influenced by the wind speed above pavement surface. The wind speed above pavement surface not only is dominated by the wind speed of atmosphere, but also it is highly related to the landform and buildings around road. However, currently there are no studies about the wind field above pavement surface in consideration of the effect of the landform and buildings. A simulation method, which is combined with geographic information system (GIS), wind data from meteorological observatory and computational fluid dynamics (CFD) software, is employed to study the effect of the landform and the wind speed of atmosphere on the wind field above pavement surface. Three cases are studied, including an urban road, a coastal road and a mountainous road. Furthermore, the wind field distribution above road surface in different wind directions was studied in our work. Results indicate that the wind field above pavement surface can be greatly affected by the landforms, buildings and wind direction. This simulation method can provide reliable results for the wind field above pavement surface. The maximum relative errors between simulated and measured wind speed can be less than 20% in the analysis of the three cases. It is recommended that the CFD simulation method is a good tool to accurately know the wind field above pavement surface. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Distinguishing glacial diamictons and landforms using till macrofabric and grain size analysis: Serra da Cabreira Mountains, NW Portugal.
- Author
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Santos, João Bessa and DeJarlais, Madison
- Subjects
GLACIAL landforms ,GRAIN size ,DEBRIS avalanches ,GLACIATION ,TILLAGE ,LANDFORMS - Abstract
Information on the nature of processes occurring in modern glaciers can be obtained through the study of diamictons and landforms that are the product of past glaciations. Macrofabric and grain size analysis of late Quaternary glacial diamictons and moraines present in several valleys of the Serra da Cabreira Mountains in northwest Portugal revealed the presence of two types of diamictons deposited in different stages and were used to re-construct the glacial paleo process history of this mountainous region. Supraglacial melt-out tills and paraglacially reworked tills by debris flows are dominant in this range. Supraglacial melt-out tills, representative of periods of glacial stability followed by recession, present girdle to transitional fabrics and coarser to medium, poorly sorted sediments. Paraglacially reworked tills by debris flows, representative of postglacial mass wasting activity, present girdle fabrics and coarser, poorly sorted sediments. These diamictons and landforms are of particular importance in the reconstruction of the glacial dynamics and history of the Serra da Cabreira Mountains due to a scarcity of chronological data based on absolute dating methods. These Atlantic mountains are also the lowest glaciated range in the Iberian Peninsula, which makes them a compelling area to investigate mountain glacial dynamics in low-elevation Atlantic ranges. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Characterization and Modernization of the Depositional System in Modern Ebinur Lake Basin, Northwest China.
- Author
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Xiang, Jianbo, Zhang, Xianghui, Liu, Jiale, Meng, Qinghao, Zhang, Yu, and Li, Xinglu
- Subjects
WATERSHEDS ,SAND dunes ,LANDFORMS ,SEDIMENTARY basins ,LAKE sediments ,SEDIMENT control - Abstract
The Ebinur Lake Basin is a typical terrestrial sedimentary Basin in Northwest China that has developed a piedmont distributive fluvial system (DFS) sedimentary environment, lake sedimentary environment, and desert sedimentary environment. The Ebinur Lake receives the sediments carried by the rivers in the basin and is the regional sedimentary center. In this study, a division scheme of modern sedimentary system tracts in the Ebinur Lake Basin was proposed. According to the landform, sedimentary environment, structure, and sedimentary system types, the Ebinur Lake Basin was divided into five system tracts. The area with high altitude and steep gradients mainly develops the rapid sedimentary system DFS, and the area with the lowest altitude in the region develops the lake sedimentary system. The main action area of climate drought and wind field is the dune sedimentary area. The wind field under the influence of hydrological climate and geomorphology has an important influence on the distribution of the sedimentary system tract. The structure determines the development of different types of sedimentary systems by controlling the topographic fluctuation and sedimentary space. Hydroclimate and geomorphology affect the development of sedimentary systems by controlling the sediment source rate in the sedimentary area. Based on the analysis of the characteristics and distribution of the modern sedimentary system in the Ebinur Lake Basin, a method for determining the level of the sedimentary system of the Ebinur Lake was established together with a plane model of the sedimentary system of the Ebinur Lake, which provides a reference for the study of the sedimentary system of continental basins. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Urban ground leases: a cross-country comparison.
- Author
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Pope, Alan R. and Young, Martin R.
- Subjects
LEASES ,LAND tenure ,BUILDING leases ,LANDFORMS ,PROPERTY rights - Abstract
The ground lease is a form of land tenure where the property rights are split between the lessor (landowner) and the lessee (land user). Additional ground lease features, such as the obligation to pay ground rent, depend on factors including the legal framework and lessor requirements. Ground lease features can lead to interpretation problems for ground leaseholders and even valuers, such as misunderstanding the extent of ground rent review. This paper examines location-based differences in order to highlight ground lease variability across countries. The term 'ground lease' is effectively a catch-all term for a tenure type that can display considerable differences depending on the location. Recognition of potential ground lease pitfalls and how ground leases differ across jurisdictions is necessary in an increasingly connected world. This paper advocates for uniform international ground lease terminology that more completely explains the extent of tenure rights of each ground lease. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Sedimentological evidence of climate-tectonic interaction in the upper Satluj catchment of NW Himalaya.
- Author
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Joshi, Moulishree and Jalal, Poonam
- Subjects
RAINFALL ,CLIMATIC zones ,LANDFORMS - Abstract
Quaternary valley fill deposits in the Upper Satluj Valley of NW Himalaya act as archives of changing climate-tectonic dynamics in a region. Quaternary landforms help in decoding the relationship between climate and tectonics. Kinnaur region is traversed by several active faults and thrusts such as the Kaurik-Chango Fault (KCF) and Sangla Detachment (SD), thereby making upper Satluj Valley tectonically active. Morphotectonic parameters such as width of valley floor (Vfw), Normalized Steepness Index (KSn) and geomorphological evidences such as the presence of huge strath terraces, narrowing of the river valley and palaeolake deposits point towards the tectonically active nature of the terrain. This arid, high elevation region is also climatically sensitive as it falls in a transient climatic zone which receives rainfall only during abnormal monsoon months. Excessive rainfall causes outburst floods, a common phenomenon in the area due to the blocking of headwater in the upper reaches of the Satluj valley. As a result, the Quaternary sequence is modified from time to time. The transition from hypo concentrated deposits to channel deposits and ponding events are prominent in the depositional sequence, resulting from a response to climate. The studied Quaternary sediments reveal that the Trans-Himalayan region of the upper Satluj valley is affected by tectonic-climate variability, making it vulnerable to geohazards. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Study of Temporal Dynamics of Urban Heat Island Surface in Padang West Sumatra, Indonesia.
- Author
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Novio, Rery, Mariya, Sri, Prarikeslan, Widya, and Ramon, Sophia Aulia
- Subjects
URBAN heat islands ,LAND surface temperature ,SURFACE temperature ,SURFACE phenomenon ,LANDFORMS - Abstract
Padang as the capital of the province, is a strategic area and also the center of the economy. Annual population growth affects changes in land use from vegetated land to built-up areas. An increase in barren land will trigger an increase in temperature. SUHI is a temperature phenomenon that occurs on the surface resulting from the increase in temperature. SUHI can be observed through surface temperature data or Land Surface Temperature. This study aims to identify changes in land surface temperature that are affected by changes in land use in the form of building density conditions. In analyzing this using Landsat 7 ETM+ imagery in 2001, 2006, 2011, 2016, and 2020. The building density measurement method LST transformations to measure surface temperature and helps the Surface Urban Heat Island phenomenon. The results of the analysis showed that there was an increase in the building density of the city of Padang over a period of 20 years. This phenomenon affects the surface temperature, indicating that the surface temperature has increased by around 0.47°C. The highest temperature from 2001-2020 occurred in 2016, with the highest temperature of 36°C. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Mass Density Variations of Landforms, Active Orogeny and Erosion in the Nepal Himalaya Derived from the Earth Gravity Model EIGEN 6C4
- Author
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Kostelecký, Jan, Kalvoda, Jan, Klokočník, Jaroslav, Bezděk, Aleš, Wang, Fawu, Series Editor, Vilimek, Vit, Series Editor, Kalvoda, Jan, editor, and Novotná, Eva, editor
- Published
- 2024
- Full Text
- View/download PDF
47. Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England.
- Author
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Davies, Neil S., McMahon, William J., and Berry, Christopher M.
- Subjects
- *
SEDIMENTARY structures , *FOSSIL trees , *SANDSTONE , *STANDING position , *LANDFORMS , *DEAD trees , *DEVONIAN Period , *FOSSIL plants - Abstract
The evolution of trees and forests through the Devonian Period fundamentally changed the Earth's land biosphere, as well as impacting physical environments and geomorphology by stabilizing sediments and interacting with flowing air and water. From the mid-Givetian Age onwards, lignophyte flora are known to have been key parts of the machinery in the so-called Devonian landscape factory, but the impact of earlier forests, dominated by less woody cladoxylopsids, are not as well understood. We report here evidence for a previously unrecognized cladoxylopsid forest landscape, archived within the Eifelian Hangman Sandstone Formation of Somerset and Devon, SW England. This unit has previously been considered palaeobotanically depauperate, but is here shown to contain the earliest fossil evidence for such trees in the British record, as well as the oldest known evidence globally for the relative position of standing trees: in common parlance, a fossil forest. In addition to abundant fossil material attributable to the cladoxylopsid tree Calamophyton, and other early Mid-Devonian flora, the sedimentary context of the plant remains sheds light on the biogeomorphic impacts of these earliest forests. The trees colonized a sizeable distributive fluvial system that was prone to seasonal disturbance events. The nature of the sedimentary system has created a bias to those facies where biogeomorphic signatures are most frequently recorded (from the distal parts of the system), but across the whole system there is evidence of plant–sediment interactions in the form of vegetation-induced sedimentary structures, rooting features and accumulations of plant debris. Plant remains are also found in nearshore facies adjacent to the distributive fluvial system, attesting to the development of a novel non-marine/marine teleconnection from the production and export of new biological sedimentary particles. The Hangman Sandstone Formation is illustrative of the revolutionary power of cladoxylopsid trees as biogeomorphic agents, forming densely spaced forests and shedding exceptionally abundant plant debris, while also impacting local landforms and sediment accumulations and profoundly changing landform resilience against flood disturbance events. These findings provide evidence that the Eifelian Stage (393.3–387.7 Ma) marks the onset of tree-driven changes to physical environments that would forever change Earth's non-marine landscapes and biosphere. Supplementary material: Details of sedimentary facies and additional images of plant fossils are available at https://doi.org/10.6084/m9.figshare.c.7084873 [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Words as Archaeological Objects: A Study of Marine Lifeways, Seascapes, and Coastal Environmental Knowledge in the Yagan-English Dictionary.
- Author
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Eidshaug, Jo Sindre P., Bjerck, Hein B., Lohndal, Terje, and Risbøl, Ole
- Subjects
- *
ENCYCLOPEDIAS & dictionaries , *WORD frequency , *UNDERWATER archaeology , *ENVIRONMENTAL literacy , *LANDFORMS , *LANDSCAPE archaeology , *HISTORICAL archaeology - Abstract
Reverend Thomas Bridges' Yagan-English dictionary (1879) has hitherto been little explored outside of linguistics but is highly valuable as a complementary source to archaeological, ethnohistorical, and ethnographic records in Tierra del Fuego (Argentina and Chile). The dictionary contains 22,800 entries and yields rich information concerning the marine lifeways of the Yagan and their and intimate knowledge about Fuegian seascapes. The idea behind this paper is that environments have strong bearings on linguistic vocabularies. Treating words as archaeological objects that map onto landscapes, we identify important landforms for Yagan marine foragers and Norwegian fisher-farmers in a comparative study of word frequencies in Bridges' dictionary and Ivar Aasen's Norwegian dictionary (1850). Moreover, we explore in detail how marine lifestyles and Fuegian seascapes emerge in Bridges' dictionary and discuss the dictionary's relevance for historical archaeology in Tierra del Fuego. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Landscape Taphonomy Predictably Complicates Demographic Reconstruction.
- Author
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Contreras, Daniel A. and Codding, Brian F.
- Subjects
- *
DISTRIBUTION (Probability theory) , *TAPHONOMY , *ARCHAEOLOGICAL excavations , *RADIOCARBON dating , *LANDFORMS - Abstract
Accurately reconstructing past human population dynamics is critical for explaining major patterns in the human past. Demand for demographic proxies has driven hopeful interest in the "dates-as-data" approach, which models past demography by assuming a relationship between population size, the production of dateable material, and the corpus of radiocarbon dates produced by archaeological research. However, several biases can affect assemblages of dates, complicating inferences about population size. One serious but potentially addressable issue centers on landscape taphonomy — the ways in which geologic processes structure the preservation and recovery of archaeological sites and/or materials at landscape scales. Here, we explore the influence of landscape taphonomy on demographic proxies. More specifically, we evaluate how well demographic proxies may be corrected for taphonomic effects with either a common generalized approach or an empirically based tailored approach. We demonstrate that frequency distributions of landforms of varying ages can be used to develop local corrections that are more accurate than either global corrections or uncorrected estimates. Using generalized scenarios and a simulated case study based on empirical data on landform ages from the Coso Basin in the western Great Basin region, we illustrate the way in which landscape taphonomy predictably complicates "dates-as-data" approaches, propose and demonstrate a new method of empirically based correction, and explore the interpretive ramifications of ignoring or correcting for taphonomic bias. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Investigating the spatial distribution of flood inundation and landforms using topographic position index (TPI) and geomorphon-based automated landform classification methods.
- Author
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Gupta, Laxmi and Dixit, Jagabandhu
- Subjects
- *
LANDFORMS , *EMERGENCY management , *NATURAL resources management , *FLOODS , *SPATIAL arrangement - Abstract
The landform of the region highly influences the dynamics of the flood and plays a crucial role in directing the water flow, affecting the speed and volume of runoff. Assam, located in northeast India, experiences floods yearly due to adverse climatic conditions and complex terrain features. The objective of the present study is to understand the landform classification of Assam using the topographic position index (TPI) and geomorphon-based automated classification of landform (ACL) method and its spatial distribution with slope, geology, soil, LULC, and flood inundation. The ACL method shows that gentle slopes or flat areas occupy the maximum area ranging from 56.17 to 68.10% for TPI‐based slope position classes, and for geomorphon, slope feature occupies 20.61–25.39% of the total area. The spatial distribution of TPI and geomorphon-based landform classification was different because TPI compares the elevation of a point to the average elevation of its neighbourhood, while geomorphon classifies the landscape into predefined landform classes based on terrain shape and the spatial arrangement of elevation values. In both models, valleys are the most dominant landform class and are mainly present in the Central and Barak valley of Assam. The built-up areas and waterbodies on vulnerable landform classes increase their flood susceptibility. About 38.08% of the inundated area was found in wide valleys and 31% of the inundated area lies under flat landforms. The present study can be effective in land use planning, sustainable natural resource management, disaster risk management, and mitigation strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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