Pub Date : 2025-06-11DOI: 10.1016/j.geogeo.2025.100420
Haritabh Rana, Tahir Mushtaq, Ranjith Anburaj
The Himalayan Belt is notably at risk for landslide occurrences, which are directly related to the region's development and economic well-being. The study area encompasses Tangni to Vishnuprayag road sector, National Highway-07 (NH-07) in Chamoli district of Uttarakhand. The primary objective of this study is to identify the zones susceptible to landslides within the region, thereby contributing to the reduction of landslide disaster risks. Knowledge driven weighted overlay method (WOM) integrating GIS and field based multiple geofactor maps has been used where each thematic map was given a rating and weighting process utilizing a heuristic approach which facilitated the generation of a landslide susceptibility map, separately for the rock and debris domain of the region. Seventy-three landslides along the road corridor and its surrounding areas, establishing a correlation between their spatial distribution and various geotechnical parameters have been considered for this study. The resulting susceptibility map documenting 73 nos. of landslide incidences in the study area indicates that low susceptibility zone accounts for 49 % of the area accomodating 8 % (06 nos.) of the total landslide incidences. The moderate susceptibility zone accounts for 30 % of the area but has 19 % (14 nos.) of the total landslide incidences and the high susceptibility zone accounts for 21 % of the area but has 73 % (53 nos.) of the total landslide incidences. Validation of the susceptibility map was conducted against historical landslide data and field observations, which confirmed its reliability. This integrated approach of WOM serves as a significant resource for land-use planning and disaster risk reduction in landslide-prone areas of the Himalayas. Furthermore, it illustrates the efficacy of the WOM for mapping landslide susceptibility, providing a replicable framework for similar terrains both within the Himalayas and in other regions.
{"title":"Impact of geofactors on landslide susceptibility using weighted overlay method: An integrated GIS and field-based analysis on NH-07, Chamoli, Uttarakhand","authors":"Haritabh Rana, Tahir Mushtaq, Ranjith Anburaj","doi":"10.1016/j.geogeo.2025.100420","DOIUrl":"10.1016/j.geogeo.2025.100420","url":null,"abstract":"<div><div>The Himalayan Belt is notably at risk for landslide occurrences, which are directly related to the region's development and economic well-being. The study area encompasses Tangni to Vishnuprayag road sector, National Highway-07 (NH-07) in Chamoli district of Uttarakhand. The primary objective of this study is to identify the zones susceptible to landslides within the region, thereby contributing to the reduction of landslide disaster risks. Knowledge driven weighted overlay method (WOM) integrating GIS and field based multiple geofactor maps has been used where each thematic map was given a rating and weighting process utilizing a heuristic approach which facilitated the generation of a landslide susceptibility map, separately for the rock and debris domain of the region. Seventy-three landslides along the road corridor and its surrounding areas, establishing a correlation between their spatial distribution and various geotechnical parameters have been considered for this study. The resulting susceptibility map documenting 73 nos. of landslide incidences in the study area indicates that low susceptibility zone accounts for 49 % of the area accomodating 8 % (06 nos.) of the total landslide incidences. The moderate susceptibility zone accounts for 30 % of the area but has 19 % (14 nos.) of the total landslide incidences and the high susceptibility zone accounts for 21 % of the area but has 73 % (53 nos.) of the total landslide incidences. Validation of the susceptibility map was conducted against historical landslide data and field observations, which confirmed its reliability. This integrated approach of WOM serves as a significant resource for land-use planning and disaster risk reduction in landslide-prone areas of the Himalayas. Furthermore, it illustrates the efficacy of the WOM for mapping landslide susceptibility, providing a replicable framework for similar terrains both within the Himalayas and in other regions.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100420"},"PeriodicalIF":0.0,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-08DOI: 10.1016/j.geogeo.2025.100417
Ngong Roger Ngia , Elie Fosso Menkem , Alexandrine N’Nanga , Christopher Fuanya , Median Yongye
Black shales deposited across the Paleocene Bolander member of the N’kapa Formation are considered important source rock and shale gas reservoirs in the Douala sub-basin. However, no studies on organic carbon and sulfur isotopes perturbation, accumulation and enrichment of organic matter in black shales exist in the sub-basin. This paper unravels paleoenvironmental reconstruction, the perturbation of organic carbon and pyrite sulfur isotopes record, and mechanism of organic matter enrichment in black shales of the Kompina-Mian and Pendanboko-Kombe areas. Multiple geochemical techniques: organic carbon isotope (δ13Corg), pyrite sulfur (δ34Spy), TOC, total sulfur abundance (TS), elemental geochemistry, mineralogy and SEM were used. Paleoclimate proxies indicates that the paleoclimatic condition was mildly-warmer and more humid. Bivariate plots and discriminant functions diagrams to delineate between active and passive tectonic settings such as DF1&2(Arc-Rift-Col)M1, DF1&2(Arc-Rift-Col)M2 and DF(A-P)M revealed that the rocks were sourced from felsic rocks with a passive tectonic setting, with little contribution from active setting. Paleoweathering proxies revealed that the source area experienced moderate chemical weathering as a result of variation in climate and sea-level changes. The proxies for paleoredox and paleosalinity conditions revealed that the sediments were deposited under anoxic sulphidic benthic brackish-water with intermediate salinity. Paleoproductivity parameters like Ba-bio, δ34Spy, δ13Corg, TOC, Mo/Al, Cu/Al and S/13Corg ratios revealed that climate, brackish-water and anoxia conditions were suitable for high primary productivity and preservation of organic matters. The depleted δ13Corg values and negative excursion along the black shale bed results from sulfate-reducing bacteria and chemoautotrophy-mediated carbon cycling under anoxia conditions. While depleted δ34Spy contents are results from biological fractionation during microbial sulfate reduction (MSR), generating pyrite framboids in sediment under strong restrictive conditions with low oxygenation. The mechanism of organic matter accumulation and enrichment demonstrates that δ13Corg and δ34Spy was anaerobically recycled by sulphate reducing bacteria and MSR processes, and the caping of benthic black shales by mudstones at shortened exposure duration, caused high primary productivity in anoxic waters. The data of this study demonstrate large climatic and oceanic anoxia fluctuations during the Paleocene influenced peleoweathering, paleosalinity, primary productivity, carbon and sulfur isotopes perturbation, and accumulation and enrichment of organic matter.
{"title":"Paleoenvironmental reconstruction and carbon and sulfur isotopes perturbation in black shales of the Paleocene Bolander member in the N’kapa Formation, Douala Sub-basin Cameroon","authors":"Ngong Roger Ngia , Elie Fosso Menkem , Alexandrine N’Nanga , Christopher Fuanya , Median Yongye","doi":"10.1016/j.geogeo.2025.100417","DOIUrl":"10.1016/j.geogeo.2025.100417","url":null,"abstract":"<div><div>Black shales deposited across the Paleocene Bolander member of the N’kapa Formation are considered important source rock and shale gas reservoirs in the Douala sub-basin. However, no studies on organic carbon and sulfur isotopes perturbation, accumulation and enrichment of organic matter in black shales exist in the sub-basin. This paper unravels paleoenvironmental reconstruction, the perturbation of organic carbon and pyrite sulfur isotopes record, and mechanism of organic matter enrichment in black shales of the Kompina-Mian and Pendanboko-Kombe areas. Multiple geochemical techniques: organic carbon isotope (δ<sup>13</sup>C<sub>org</sub>), pyrite sulfur (δ<sup>34</sup>S<sub>py</sub>), TOC, total sulfur abundance (TS), elemental geochemistry, mineralogy and SEM were used. Paleoclimate proxies indicates that the paleoclimatic condition was mildly-warmer and more humid. Bivariate plots and discriminant functions diagrams to delineate between active and passive tectonic settings such as DF1&2(Arc-Rift-Col)<sub>M1,</sub> DF1&2(Arc-Rift-Col)<sub>M2</sub> and DF(A-P)<sub>M</sub> revealed that the rocks were sourced from felsic rocks with a passive tectonic setting, with little contribution from active setting. Paleoweathering proxies revealed that the source area experienced moderate chemical weathering as a result of variation in climate and sea-level changes. The proxies for paleoredox and paleosalinity conditions revealed that the sediments were deposited under anoxic sulphidic benthic brackish-water with intermediate salinity. Paleoproductivity parameters like Ba-bio, δ<sup>34</sup>S<sub>py</sub>, δ<sup>13</sup>C<sub>org,</sub> TOC, Mo/Al, Cu/Al and S/<sup>13</sup>C<sub>org</sub> ratios revealed that climate, brackish-water and anoxia conditions were suitable for high primary productivity and preservation of organic matters. The depleted δ<sup>13</sup>C<sub>org</sub> values and negative excursion along the black shale bed results from sulfate-reducing bacteria and chemoautotrophy-mediated carbon cycling under anoxia conditions. While depleted δ<sup>34</sup>Spy contents are results from biological fractionation during microbial sulfate reduction (MSR), generating pyrite framboids in sediment under strong restrictive conditions with low oxygenation. The mechanism of organic matter accumulation and enrichment demonstrates that δ<sup>13</sup>C<sub>org</sub> and δ<sup>34</sup>Spy was anaerobically recycled by sulphate reducing bacteria and MSR processes, and the caping of benthic black shales by mudstones at shortened exposure duration, caused high primary productivity in anoxic waters. The data of this study demonstrate large climatic and oceanic anoxia fluctuations during the Paleocene influenced peleoweathering, paleosalinity, primary productivity, carbon and sulfur isotopes perturbation, and accumulation and enrichment of organic matter.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100417"},"PeriodicalIF":0.0,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-07DOI: 10.1016/j.geogeo.2025.100418
Md. Kamrul Hossain , Md. Anisul Kabir , Mohammad Omar Faruk Molla , Md. Anik Hossain , Most. Suria Khatun , Miss Nushrat Jahan Lima , Sazal Kumar , Rafiquel Islam
Soil salinity is a critical environmental challenge within coastal systems, posing a significant threat to vegetation in the territory. This study investigates the spatial distribution of soil salinity in coastal Bangladesh and its relationships with topography and vegetation indices. Seventy-five soil samples (0–15 cm depth) were collected using a stratified random sampling method. Moisture content, electrical conductivity (EC), pH, and temperature were all measured utilizing electrical sensor-based optimized tools. Topographic parameters including elevation, slope, aspect, and topographic wetness index (TWI), were derived from the Digital Elevation Model (DEM) using ArcGIS. Sentinel-2A imagery was utilized to analyze salinity–vegetation interactions through spectral indices such as CRSI, GARI, NDVI, GNDVI, GDVI, and NDI. Results showed that soil salinity ranged from 0.68 to 25.88 dS/m, averaging 6.08 dS/m. A strong positive correlation was observed between soil moisture and salinity (r = 0.87). Hotspot analysis revealed the southern region as a salinity hotspot, indicating a north-to-south increasing salinity gradient. Furthermore, linear regression showed a strong negative relationship between elevation and salinity (R² = 0.91) in regions above 15 m, while slope, aspect, and TWI were insignificant. Vegetation indices, NDVI, and CRSI demonstrated moderate negative correlations with salinity, indicating that higher salinity leads to lower plant health. This study underscores the pivotal influence of topography, especially elevation, on soil salinity distribution and demonstrates the effectiveness of vegetation indices for salinity monitoring. These findings support the use of precision agriculture and informed land-use planning to enhance sustainability and resilience in Bangladesh’s salinity-affected coastal regions.
{"title":"Geospatial analysis of soil salinity dynamics: Exploring topographic and vegetation influences in coastal Bangladesh","authors":"Md. Kamrul Hossain , Md. Anisul Kabir , Mohammad Omar Faruk Molla , Md. Anik Hossain , Most. Suria Khatun , Miss Nushrat Jahan Lima , Sazal Kumar , Rafiquel Islam","doi":"10.1016/j.geogeo.2025.100418","DOIUrl":"10.1016/j.geogeo.2025.100418","url":null,"abstract":"<div><div>Soil salinity is a critical environmental challenge within coastal systems, posing a significant threat to vegetation in the territory. This study investigates the spatial distribution of soil salinity in coastal Bangladesh and its relationships with topography and vegetation indices. Seventy-five soil samples (0–15 cm depth) were collected using a stratified random sampling method. Moisture content, electrical conductivity (EC), pH, and temperature were all measured utilizing electrical sensor-based optimized tools. Topographic parameters including elevation, slope, aspect, and topographic wetness index (TWI), were derived from the Digital Elevation Model (DEM) using ArcGIS. Sentinel-2A imagery was utilized to analyze salinity–vegetation interactions through spectral indices such as CRSI, GARI, NDVI, GNDVI, GDVI, and NDI. Results showed that soil salinity ranged from 0.68 to 25.88 dS/m, averaging 6.08 dS/m. A strong positive correlation was observed between soil moisture and salinity (<em>r</em> = 0.87). Hotspot analysis revealed the southern region as a salinity hotspot, indicating a north-to-south increasing salinity gradient. Furthermore, linear regression showed a strong negative relationship between elevation and salinity (<em>R</em>² = 0.91) in regions above 15 m, while slope, aspect, and TWI were insignificant. Vegetation indices, NDVI, and CRSI demonstrated moderate negative correlations with salinity, indicating that higher salinity leads to lower plant health. This study underscores the pivotal influence of topography, especially elevation, on soil salinity distribution and demonstrates the effectiveness of vegetation indices for salinity monitoring. These findings support the use of precision agriculture and informed land-use planning to enhance sustainability and resilience in Bangladesh’s salinity-affected coastal regions.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100418"},"PeriodicalIF":0.0,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since apatite is capable to adsorb and retain radionuclides, the removal of uranyl (UO22+) ions from two Ca-containing technogenic and model solutions (1–2 g/L of Ca) was studied when neutralized with sodium hydrogen phosphate solution Na2HPO4. Chemical composition of the sediments was analyzed by XPS and their structure was refined by XRD. The hydroxyapatite formation was confirmed. XRD proves that the two samples contained additional CaH(PO4) ∙ (H2O)2 (brushite), in which calcium changes to uranium of up to 15 % in a model solution. When identifying the oxidation state of uranium the presence of U4+, U5+ and U6+ was noticed with U5+ of up to 30–35 at. % from the total.
SEM-EDS did not allow to determine location of the phases with an uranium content over 14 %, for example Ca(UO2)2(PO4)2·11H2O (autunite) or other uranium phosphates. Uranium is detected at the grain rims, indicating a sorption nature of its accumulation. At the same time, thermodynamic computations showed the possible formation of independent uranium phases, such as ß-UO2.333, ß-UO2(OH)2 and NaUO2O(OH) (clarkeite), at the measured Eh-pH. We believe that the supersaturation of solutions and the spontaneous formation of hydroxyapatite and brushite solid particles led to a change in the initial Ca/PO4 ratio, where the P/Ca and Ca/O ratios, as well as the elemental composition in the near-surface layer of three sediments, are not strictly constant. There have been no similar studies on uranium, and our results demonstrate the need for further studies on the influence of uranium on apatite crystallization. Stability of phosphate phases shows the high efficiency of phosphate safety barriers for the uranium recovery facilities and these processes can be used for the water purification of polluted aquifers.
{"title":"Uranium uptake by phosphate minerals from Ca-containing technogenic solutions: Experimental study","authors":"А.Е. Boguslavsky , O.L. Gaskova , S.M. Sofronova , А.А. Saraev , Z.S. Vinokurov , А.V. Safonov","doi":"10.1016/j.geogeo.2025.100415","DOIUrl":"10.1016/j.geogeo.2025.100415","url":null,"abstract":"<div><div>Since apatite is capable to adsorb and retain radionuclides, the removal of uranyl (UO<sub>2</sub><sup>2+</sup>) ions from two Ca-containing technogenic and model solutions (1–2 g/L of Ca) was studied when neutralized with sodium hydrogen phosphate solution Na<sub>2</sub>HPO<sub>4</sub>. Chemical composition of the sediments was analyzed by XPS and their structure was refined by XRD. The hydroxyapatite formation was confirmed. XRD proves that the two samples contained additional CaH(PO<sub>4</sub>) ∙ (H<sub>2</sub>O)<sub>2</sub> (brushite), in which calcium changes to uranium of up to 15 % in a model solution. When identifying the oxidation state of uranium the presence of U<sup>4+</sup>, U<sup>5+</sup> and U<sup>6+</sup> was noticed with U<sup>5+</sup> of up to 30–35 at. % from the total.</div><div>SEM-EDS did not allow to determine location of the phases with an uranium content over 14 %, for example Ca(UO<sub>2</sub>)<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>·11H<sub>2</sub>O (autunite) or other uranium phosphates. Uranium is detected at the grain rims, indicating a sorption nature of its accumulation. At the same time, thermodynamic computations showed the possible formation of independent uranium phases, such as ß-UO<sub>2.333</sub>, ß-UO<sub>2</sub>(OH)<sub>2</sub> and NaUO<sub>2</sub>O(OH) (clarkeite), at the measured Eh-pH. We believe that the supersaturation of solutions and the spontaneous formation of hydroxyapatite and brushite solid particles led to a change in the initial Ca/PO<sub>4</sub> ratio, where the P/Ca and Ca/O ratios, as well as the elemental composition in the near-surface layer of three sediments, are not strictly constant. There have been no similar studies on uranium, and our results demonstrate the need for further studies on the influence of uranium on apatite crystallization. Stability of phosphate phases shows the high efficiency of phosphate safety barriers for the uranium recovery facilities and these processes can be used for the water purification of polluted aquifers.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100415"},"PeriodicalIF":0.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Tagu mining area, located in the Myeik region of Southern Myanmar, hosts significant Sn-W (tin-tungsten) mineralisation associated with granitoid intrusions. In the Tagu tin-tungsten deposit, mineralized quartz veins, nearly oriented in an east-west direction and either vertical or steeply dipping, are hosted by both Cretaceous to Eocene granite and Carboniferous to Early Permian metasedimentary rocks. Understanding the timing and evolution of these granitoids is crucial for unraveling the ore genesis and metallogenic implications of this economically important mineralized region. Zircon and cassiterite are ideal for geochronological analysis, as they preserve crystallization ages and offer key insights into a region's geological and metallogenic history. This study employed LA-ICP-MS U-Pb geochronology on zircon and cassiterite to determine the emplacement chronology of Sn-W-bearing granitoids, providing critical understanding of Sn-W ore deposit formation in southern Myanmar. LA ICP-MS zircon U-Pb age data of the host granitic rocks of the Tagu W-Sn deposit gave an age of 85.3 ± 1.5 Ma. Two cassiterite samples from the Tagu deposit yielded U-Pb ages of 88.0 ± 3.0 Ma and 75.6 ± 4.9 Ma and the ages are broadly similar to the age of host granite intrusion. Both zircon and cassiterite are well-zoned in the CL images which is suggesting their magmatic affinity. Geochemical characteristics and U-Pb ages of zircon and cassiterite indicate that the timing of the granitoid intrusions and the W-Sn mineralisation of the Tagu area is related to the post-collisional magmatism generated by the Neo-Tethyan Indian Ocean subduction and collision between the western Myanmar Terrane and the Sibumasu Terrane during the Cretaceous.
{"title":"U-Pb zircon and cassiterite geochronology of Sn-W bearing granitoids at the Tagu mining area in the Myeik region, Southern Myanmar: Insight into ore genesis and metallogenic implication","authors":"Kyaw Thu Htun , Khin Zaw , Ivan Belousov , Kotaro Yonezu , Charles Makoundi , Koichiro Watanabe , Karsten Goemann","doi":"10.1016/j.geogeo.2025.100416","DOIUrl":"10.1016/j.geogeo.2025.100416","url":null,"abstract":"<div><div>The Tagu mining area, located in the Myeik region of Southern Myanmar, hosts significant Sn-W (tin-tungsten) mineralisation associated with granitoid intrusions. In the Tagu tin-tungsten deposit, mineralized quartz veins, nearly oriented in an east-west direction and either vertical or steeply dipping, are hosted by both Cretaceous to Eocene granite and Carboniferous to Early Permian metasedimentary rocks. Understanding the timing and evolution of these granitoids is crucial for unraveling the ore genesis and metallogenic implications of this economically important mineralized region. Zircon and cassiterite are ideal for geochronological analysis, as they preserve crystallization ages and offer key insights into a region's geological and metallogenic history. This study employed LA-ICP-MS U-Pb geochronology on zircon and cassiterite to determine the emplacement chronology of Sn-W-bearing granitoids, providing critical understanding of Sn-W ore deposit formation in southern Myanmar. LA ICP-MS zircon U-Pb age data of the host granitic rocks of the Tagu W-Sn deposit gave an age of 85.3 ± 1.5 Ma. Two cassiterite samples from the Tagu deposit yielded U-Pb ages of 88.0 ± 3.0 Ma and 75.6 ± 4.9 Ma and the ages are broadly similar to the age of host granite intrusion. Both zircon and cassiterite are well-zoned in the CL images which is suggesting their magmatic affinity. Geochemical characteristics and U-Pb ages of zircon and cassiterite indicate that the timing of the granitoid intrusions and the W-Sn mineralisation of the Tagu area is related to the post-collisional magmatism generated by the Neo-Tethyan Indian Ocean subduction and collision between the western Myanmar Terrane and the Sibumasu Terrane during the Cretaceous.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100416"},"PeriodicalIF":0.0,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-28DOI: 10.1016/j.geogeo.2025.100414
Idarwati , Budhi Setiawan , Stevanus Nalendra Jati , Yogie Zulkurnia Rochmana , Elisabet Dwi Mayasari , Muhammad Rendana
Gilas River is one of the areas that shows interesting geological structures due to the meeting between West Sumatra and the Woyla Block. This boudine and microfold formation scheme aims to reveal the tectonics of Sumatra Island during the Late Cretaceous to Tertiary period, especially those found in the Gilas River. The methods used are DEMNas (National Digital Elevation Model) analysis, outcrop observation, and deformation element data analysis. The data obtained is then used to reconstruct structural architecture models, force-related deformation mechanisms, and the tectonic evolution of the area. The Gilas Strip experienced several tectonic events based on the results of research at the observation site. Based on the results of the analysis, it is known that the first structure is a foliation in the phyllite rock which is oriented ESE-WNW due to the first deformation in the Triassic period. The second deformation occurred in the Late Cretaceous period which produced the NNE-SSW trending Dextral Milling Fault (S2). The formation of micro folds with the fold axis having a position of N118°E/80 found at observation location IWD 4 and boudine structure with ENE-WSW direction at observation location IWD 5 is the result of the second deformation (D2). The Gilas Right Horizontal Fault produces an antithetic fault in the form of a left horizontal fault with a relative direction of E-W (S2′). The last period is the formation of a conjugate shear fault at the observation location IWD 3 due to Neogene tectonic deformation (D3), with a relative N-S fault direction.
{"title":"Schematic formation of boudine granite and microfold phyllite of Gilas River: Implications for Triassic to Tertiary tectonics of Garba Hill, South Ogan Komering Ulu Regency, South Sumatra Province","authors":"Idarwati , Budhi Setiawan , Stevanus Nalendra Jati , Yogie Zulkurnia Rochmana , Elisabet Dwi Mayasari , Muhammad Rendana","doi":"10.1016/j.geogeo.2025.100414","DOIUrl":"10.1016/j.geogeo.2025.100414","url":null,"abstract":"<div><div>Gilas River is one of the areas that shows interesting geological structures due to the meeting between West Sumatra and the Woyla Block. This boudine and microfold formation scheme aims to reveal the tectonics of Sumatra Island during the Late Cretaceous to Tertiary period, especially those found in the Gilas River. The methods used are DEMNas (National Digital Elevation Model) analysis, outcrop observation, and deformation element data analysis. The data obtained is then used to reconstruct structural architecture models, force-related deformation mechanisms, and the tectonic evolution of the area. The Gilas Strip experienced several tectonic events based on the results of research at the observation site. Based on the results of the analysis, it is known that the first structure is a foliation in the phyllite rock which is oriented ESE-WNW due to the first deformation in the Triassic period. The second deformation occurred in the Late Cretaceous period which produced the NNE-SSW trending Dextral Milling Fault (S2). The formation of micro folds with the fold axis having a position of N118°E/80 found at observation location IWD 4 and boudine structure with ENE-WSW direction at observation location IWD 5 is the result of the second deformation (D2). The Gilas Right Horizontal Fault produces an antithetic fault in the form of a left horizontal fault with a relative direction of E-W (S2′). The last period is the formation of a conjugate shear fault at the observation location IWD 3 due to Neogene tectonic deformation (D3), with a relative N-S fault direction.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100414"},"PeriodicalIF":0.0,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-27DOI: 10.1016/j.geogeo.2025.100413
Zahid Habib , Ajay Kumar , Riyaz Ahmad Mir , Irfan Maqbool Bhat , Waseem Qader , Rosan Kumar Mallik
This study examines the geotechnical properties of slope overburden material from Banihal to Ramban road section of National Highway-44 (NH44), Jammu and Kashmir, Western Himalaya. This region consists of Early Palaeozoic rock formations and is prone to mass wasting. Extensive development activities have exacerbated slope instability in this area. For geotechnical analysis, 40 undisturbed soil samples (USS) were collected and assessed for various parameters. Average values indicate moderate natural moisture content (11.6%), liquid limit (32%), plastic limit (24%), and plasticity index (7%), bulk density (1.6 g/cm³), dry density (1.4 g/cm³), cohesion (0.25 kg/cm²), internal friction angle (38°), void ratio (0.8), porosity (0.44%), and specific gravity (2.5%). The observed geotechnical results suggest moderate bearing capacity of the studied slopes, but increased landslide risk due to low cohesion in high moisture conditions. Therefore, these results may act as a policy document, aiding in land-use planning and identifying suitable sites for engineering structures.
{"title":"Geotechnical analysis and landslide susceptibility of overburden slope material in the Jammu and Kashmir, Western Himalaya","authors":"Zahid Habib , Ajay Kumar , Riyaz Ahmad Mir , Irfan Maqbool Bhat , Waseem Qader , Rosan Kumar Mallik","doi":"10.1016/j.geogeo.2025.100413","DOIUrl":"10.1016/j.geogeo.2025.100413","url":null,"abstract":"<div><div>This study examines the geotechnical properties of slope overburden material from Banihal to Ramban road section of National Highway-44 (NH44), Jammu and Kashmir, Western Himalaya. This region consists of Early Palaeozoic rock formations and is prone to mass wasting. Extensive development activities have exacerbated slope instability in this area. For geotechnical analysis, 40 undisturbed soil samples (USS) were collected and assessed for various parameters. Average values indicate moderate natural moisture content (11.6%), liquid limit (32%), plastic limit (24%), and plasticity index (7%), bulk density (1.6 g/cm³), dry density (1.4 g/cm³), cohesion (0.25 kg/cm²), internal friction angle (38°), void ratio (0.8), porosity (0.44%), and specific gravity (2.5%). The observed geotechnical results suggest moderate bearing capacity of the studied slopes, but increased landslide risk due to low cohesion in high moisture conditions. Therefore, these results may act as a policy document, aiding in land-use planning and identifying suitable sites for engineering structures.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100413"},"PeriodicalIF":0.0,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-22DOI: 10.1016/j.geogeo.2025.100411
Kufre Richard Ekanem, Nyakno Jimmy George, Aniekan Martin Ekanem, Ndifreke Inyang Udosen, Jewel Emem Thomas
This study deploys methods of vertical electrical sounding (VES), electrical resistivity tomography (ERT), and georesistivity-hydrodynamic correlation to evaluate groundwater quality and lithological changes in the river channel aquifer system of Akwa Ibom State, Southern Nigeria. In addition to revealing groundwater recharge and discharge zones, resistivity anomalies combined with borehole lithology also highlight the potential for contamination from rivers, landfills, and agricultural runoff. According to georesistivity studies, there are four different subsurface layers. The topmost layer shows resistivity fluctuations between 14.1 and 2345.4 Ωm (mean: 501.1 Ωm, CV: 105%), which are caused by human activity and surface erosion. High thickness variations (1.8–102.8 m) and resistivity values (8.1–1847.1 Ωm) are observed in the second layer, a fine sand aquifer. Medium to coarse sands make up the third layer, which exhibits resistivity values ranging from 1.1 to 2408.9 Ωm (CV: 124%). Although the thickness of the fourth layer is unknown, its resistivity values range from 12.3 to 2128.2 Ωm. 40.7% of the region is made up of high-energy aquifers (HK: ρ1 > ρ2 < ρ3 > ρ4), 14.8% are Q-type (ρ1 > ρ2 > ρ3), and 14.8% are H-type (ρ1 < ρ2 > ρ3), according to VES curve classifications. These conditions imply high permeability, transmissivity, and groundwater flow, all of which jeopardize groundwater sanitation. The percentage of sampling sites with low-energy aquifers with limited storage capacity is just 3.7%. High-resistivity zones correlate to compacted formations, whereas low-resistivity zones near river channels are identified as active recharging locations using resistivity mapping. It is confirmed by borehole lithology that fine, gravelly sands predominate in groundwater-bearing units. Hydraulic conductivity, permeability, and transmissivity range from 0.52 to 31.45 m/day, 788.39 to 51,681.97 mD, and 18.72 to 1988.27 m²/day, respectively, according to hydrodynamic study. The Dar Zarouk characteristics, which range from 0.015 to 7.194 Ω⁻¹ for longitudinal conductance, categorize protective capacities as dominantly weak (63%), moderate (15%), good (11%), or very good (11%). Overall, this study demonstrates how intricately groundwater quality, hydrodynamics, and lithology interact within the river channel aquifer system. As inferred from the results, significant binary correlations exist between depth and aquifer thickness, water resistivity and bulk resistivity, transverse resistance and bulk resistivity, longitudinal conductance and bulk resistivity, as well as water resistivity and transverse resistance. Moreover, hydraulic conductivity exhibits a strong correlation with both permeability and transmissibility. In Nigeria's
{"title":"Georesistivity assessment of lithological and hydrodynamic factors in groundwater sanitation of Akwa Ibom river channel aquifer system","authors":"Kufre Richard Ekanem, Nyakno Jimmy George, Aniekan Martin Ekanem, Ndifreke Inyang Udosen, Jewel Emem Thomas","doi":"10.1016/j.geogeo.2025.100411","DOIUrl":"10.1016/j.geogeo.2025.100411","url":null,"abstract":"<div><div>This study deploys methods of vertical electrical sounding (VES), electrical resistivity tomography (ERT), and georesistivity-hydrodynamic correlation to evaluate groundwater quality and lithological changes in the river channel aquifer system of Akwa Ibom State, Southern Nigeria. In addition to revealing groundwater recharge and discharge zones, resistivity anomalies combined with borehole lithology also highlight the potential for contamination from rivers, landfills, and agricultural runoff. According to georesistivity studies, there are four different subsurface layers. The topmost layer shows resistivity fluctuations between 14.1 and 2345.4 Ωm (mean: 501.1 Ωm, CV: 105%), which are caused by human activity and surface erosion. High thickness variations (1.8–102.8 m) and resistivity values (8.1–1847.1 Ωm) are observed in the second layer, a fine sand aquifer. Medium to coarse sands make up the third layer, which exhibits resistivity values ranging from 1.1 to 2408.9 Ωm (CV: 124%). Although the thickness of the fourth layer is unknown, its resistivity values range from 12.3 to 2128.2 Ωm. 40.7% of the region is made up of high-energy aquifers (HK: <em>ρ</em><sub>1</sub> > <em>ρ</em><sub>2</sub> < <em>ρ</em><sub>3</sub> > <em>ρ</em><sub>4</sub>), 14.8% are Q-type (<em>ρ</em><sub>1</sub> > <em>ρ</em><sub>2</sub> > <em>ρ</em><sub>3</sub>), and 14.8% are H-type (<em>ρ</em><sub>1</sub> < <em>ρ</em><sub>2</sub> > <em>ρ</em><sub>3</sub>), according to VES curve classifications. These conditions imply high permeability, transmissivity, and groundwater flow, all of which jeopardize groundwater sanitation. The percentage of sampling sites with low-energy aquifers with limited storage capacity is just 3.7%. High-resistivity zones correlate to compacted formations, whereas low-resistivity zones near river channels are identified as active recharging locations using resistivity mapping. It is confirmed by borehole lithology that fine, gravelly sands predominate in groundwater-bearing units. Hydraulic conductivity, permeability, and transmissivity range from 0.52 to 31.45 m/day, 788.39 to 51,681.97 mD, and 18.72 to 1988.27 m²/day, respectively, according to hydrodynamic study. The Dar Zarouk characteristics, which range from 0.015 to 7.194 Ω⁻¹ for longitudinal conductance, categorize protective capacities as dominantly weak (63%), moderate (15%), good (11%), or very good (11%). Overall, this study demonstrates how intricately groundwater quality, hydrodynamics, and lithology interact within the river channel aquifer system. As inferred from the results, significant binary correlations exist between depth and aquifer thickness, water resistivity and bulk resistivity, transverse resistance and bulk resistivity, longitudinal conductance and bulk resistivity, as well as water resistivity and transverse resistance. Moreover, hydraulic conductivity exhibits a strong correlation with both permeability and transmissibility. In Nigeria's","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100411"},"PeriodicalIF":0.0,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natural electric field traverses (3) consisting of eighteen (18) VEMs points in each traverse 1 m apart were conducted across the proposed weir axis at Ogbesse River in the Iju-Itaogbolu area, to determine the thickness of overburden materials and depth to bed rock at the proposed weir site. Field investigations were conducted using the PQWT GT 500 series. Results revealed five (5) geo-electric layers with varying thickness in place, which included the topsoil, clayey unit, sand unit, and significantly weathered and fractured basement. The result also showed the presence of alluvium deposits in the area which is approximately 118 m² and varies between 3 and 18 m beneath the study area. The average thickness and saturation of the subsurface materials are particularly significant, with consequences leaning toward a high permeability of the sandy layer below the clay bed which has been partly exposed at the surface in the south-eastern section of the proposed weir axis. The proposed weir axis exhibited a regolith thickness ranging from 3.86 to 16.22 m, notably fractured at shallow and deep sections. These characteristics were observed across the proposed weir axis, increasing in magnitude and numbers upstream of the proposed weir axis. The conductivity of these fractured zones is indicative of a significant saturation. Depth to bed rock and thickness of overburden materials in the study area is however not uniform as observed from the results, indicating the fairly undulating surface of the bed rock in the study area. This study has provided useful information on the cause of failure experienced in the previous weir located 100 m upstream of the proposed weir in the past.
{"title":"Determination of depth to basement using natural electric field method (NEFM) in a proposed weir at Iju-Itaogbolu, SW Nigeria","authors":"Philomina Nkeonye Okanigbuan , Edore Festus Omozeje , Oluwatoyin Francis Ijasan , Uyiosa Osagie Aigbe","doi":"10.1016/j.geogeo.2025.100403","DOIUrl":"10.1016/j.geogeo.2025.100403","url":null,"abstract":"<div><div>Natural electric field traverses (3) consisting of eighteen (18) VEMs points in each traverse 1 m apart were conducted across the proposed weir axis at Ogbesse River in the Iju-Itaogbolu area, to determine the thickness of overburden materials and depth to bed rock at the proposed weir site. Field investigations were conducted using the PQWT GT 500 series. Results revealed five (5) geo-electric layers with varying thickness in place, which included the topsoil, clayey unit, sand unit, and significantly weathered and fractured basement. The result also showed the presence of alluvium deposits in the area which is approximately 118 m² and varies between 3 and 18 m beneath the study area. The average thickness and saturation of the subsurface materials are particularly significant, with consequences leaning toward a high permeability of the sandy layer below the clay bed which has been partly exposed at the surface in the south-eastern section of the proposed weir axis. The proposed weir axis exhibited a regolith thickness ranging from 3.86 to 16.22 m, notably fractured at shallow and deep sections. These characteristics were observed across the proposed weir axis, increasing in magnitude and numbers upstream of the proposed weir axis. The conductivity of these fractured zones is indicative of a significant saturation. Depth to bed rock and thickness of overburden materials in the study area is however not uniform as observed from the results, indicating the fairly undulating surface of the bed rock in the study area. This study has provided useful information on the cause of failure experienced in the previous weir located 100 m upstream of the proposed weir in the past.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100403"},"PeriodicalIF":0.0,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Al Hoceima region is one of the most seismically vulnerable areas in northern Morocco due to its proximity to the Africa–Eurasia plate convergence. This study presents an examination of geographic and temporal variations of the correlation fractal dimension (Dc value) and the seismic b-value in the Al Hoceima city and adjoining region, Morocco. The data file is prepared from the International Seismological Center (ISC) catalog spanning from September 1965 to April 2023, which includes 1301 earthquakes having magnitude of completeness Mc = 3.6. The maximum likelihood technique is used to estimate the b-value of the Gutenberg-Richter law, and the correlation integral technique to estimate the Dc value. Among the three approaches used for estimation, the first involves a temporal window that shifts in five-year increments. The second employs spatial sliding windows while keeping the latitude constant, and the third utilizes a spatial sliding window with a fixed longitude. The average value of the parameters b was estimated to be (1.1 ± 0.1) from the first approach, (1.45 ± 0.1) from the second approach and (1.52 ± 0.15) from the third approach. The average values of the spatial fractal dimension estimated from the three techniques are respectively (0.68 ± 0.04), (0.62 ± 0.04) and (0.37 ± 0.11). According to our results, the Dc/b ratio is smaller than 0.54 for Approach 1, smaller than 0.6 for Approach 2, and greater than 0.33 for Approach 3. This study found a strong positive correlation in the temporal approach while weak positive and negative correlations between the Dc value and the b-value for both the spatial approaches. The outcome of this study offers new understanding of the fractal characteristics of earthquake distribution in the Al Hoceima region of Morocco.
Al Hoceima地区是摩洛哥北部最易受地震影响的地区之一，因为它靠近非洲-欧亚板块交汇处。本研究提出了相关分形维数（Dc值）和地震b值在Al Hoceima市和邻近地区，摩洛哥的地理和时间变化的检查。该数据文件是根据国际地震中心（ISC）从1965年9月到2023年4月的目录编制的，其中包括1301次地震，完整度Mc = 3.6级。用极大似然法估计古腾堡-里希特定律的b值，用相关积分法估计直流值。在用于估计的三种方法中，第一种方法涉及一个以五年为单位的时间窗口。第二种方法在保持纬度不变的情况下使用空间滑动窗口，第三种方法使用固定经度的空间滑动窗口。第一种方法估计参数b的平均值为（1.1±0.1），第二种方法估计参数b的平均值为（1.45±0.1），第三种方法估计参数b的平均值为（1.52±0.15）。三种方法的空间分形维数平均值分别为（0.68±0.04）、（0.62±0.04）和（0.37±0.11）。根据我们的结果，方法1的Dc/b比小于0.54，方法2小于0.6，方法3大于0.33。研究发现，在时间方法中，Dc值与b值存在较强的正相关关系，而在空间方法中，Dc值与b值存在较弱的正相关和负相关关系。本研究结果对摩洛哥Al Hoceima地区地震分布的分形特征提供了新的认识。
{"title":"Fractal characteristics of earthquake occurrence in Al Hoceima city and its adjoining region, Morocco","authors":"Abderrahim Boulanouar , Ram Krishna Tiwari , Zian Ahmed , Harihar Paudyal , Abdelaali Rahmouni","doi":"10.1016/j.geogeo.2025.100402","DOIUrl":"10.1016/j.geogeo.2025.100402","url":null,"abstract":"<div><div>Al Hoceima region is one of the most seismically vulnerable areas in northern Morocco due to its proximity to the Africa–Eurasia plate convergence. This study presents an examination of geographic and temporal variations of the correlation fractal dimension (Dc value) and the seismic b-value in the Al Hoceima city and adjoining region, Morocco. The data file is prepared from the International Seismological Center (ISC) catalog spanning from September 1965 to April 2023, which includes 1301 earthquakes having magnitude of completeness Mc = 3.6. The maximum likelihood technique is used to estimate the b-value of the Gutenberg-Richter law, and the correlation integral technique to estimate the Dc value. Among the three approaches used for estimation, the first involves a temporal window that shifts in five-year increments. The second employs spatial sliding windows while keeping the latitude constant, and the third utilizes a spatial sliding window with a fixed longitude. The average value of the parameters b was estimated to be (1.1 ± 0.1) from the first approach, (1.45 ± 0.1) from the second approach and (1.52 ± 0.15) from the third approach. The average values of the spatial fractal dimension estimated from the three techniques are respectively (0.68 ± 0.04), (0.62 ± 0.04) and (0.37 ± 0.11). According to our results, the Dc/b ratio is smaller than 0.54 for Approach 1, smaller than 0.6 for Approach 2, and greater than 0.33 for Approach 3. This study found a strong positive correlation in the temporal approach while weak positive and negative correlations between the Dc value and the b-value for both the spatial approaches. The outcome of this study offers new understanding of the fractal characteristics of earthquake distribution in the Al Hoceima region of Morocco.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 3","pages":"Article 100402"},"PeriodicalIF":0.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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