{"title":"Chronology, Geochemical Characterisation and Tectonic Background of Early Cretaceous Volcanic Rocks in the Lengjimanda Plate, Da Hinggan Mountains","authors":"Wang ShiChang, Hao YuJie, Tang Zhen, Shi Lu","doi":"10.1002/gj.5151","DOIUrl":"https://doi.org/10.1002/gj.5151","url":null,"abstract":"<div>\u0000 \u0000 <p>The Lengjimanda Plate in the central Da Hinggan Mountains is mainly composed of a series of acid volcanic rocks such as rhyolites and rhyolitic crystal tuffs of the Early Cretaceous Baiyingaolao and Guanghua formations. LA-ICP-MS zircon U–Pb dating indicates that rhyolites of the Baiyingaolao Formation formed between 140 and 137 Ma, while rhyolites of the Guanghua Formation formed between 129 and 128 Ma. Rocks of the Baiyingaolao Formation exhibit the characteristics of high silica contents, alkali enrichment and aluminium depletion, thus resembling A-type granites. They show significant fractionation of light and heavy rare earth elements with a pronounced negative Eu anomaly. They zircon <sup>176</sup>Hf/<sup>177</sup>Hf ratios range from 0.282932 to 0.252800, with an average <i>ε</i>\u0000 <sub>Hf</sub>(<i>t</i>) value of +1.28; (<sup>87</sup>Sr/<sup>86</sup>Sr)<sub>\u0000 <i>i</i>\u0000 </sub> ranges from 0.68848 to 0.70068, with ε<sub>Nd</sub>(<i>t</i>) ranging from +1.4 to +3.7; and <i>t</i>\u0000 <sub>DM2</sub> ranges from 629 to 817 Ma, indicating magma derived from newly formed young crustal material after the closure of the Mongolian-Okhotsk Ocean. The volcanic rocks of the Guanghua Formation have characteristics that are similar to I-Type granites, with silica and alkali enrichment and Ca and Mg depletion. They also show a right-skewed “V”-shaped pattern in their REE distribution curves, with a strong negative Eu anomaly. The zircon <sup>176</sup>Hf/<sup>177</sup>Hf ratios range from 0.282887 to 0.282986, with an average <i>ε</i>\u0000 <sub>Hf</sub>(<i>t</i>) value of +8.78; (<sup>87</sup>Sr/<sup>86</sup>Sr)<sub>i</sub> ranges from 0.70060 to 0.70096, with <i>ε</i>\u0000 <sub>Nd</sub>(<i>t</i>) ranging from +3.0 to +3.8; and <i>t</i>\u0000 <sub>DM2</sub> ranges from 616 to 677 Ma, indicating the partial melting of depleted mantle-derived mafic lower crustal material, influenced by the closure of the Mongolian-Okhotsk Ocean and subduction of the ancient Pacific Plate.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1653-1681"},"PeriodicalIF":1.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ibrahim Yousuf, Talat Ahmad, D. V. Subba Rao, Roohi Irshad, S. Balakrishnan
{"title":"Geochemistry, Geochronology and Petrogenesis of the Proterozoic Betul–Chhindwara Bimodal Volcanics: Constraints on the Evolution of the Central Indian Tectonic Zone, Central Indian Shield","authors":"Ibrahim Yousuf, Talat Ahmad, D. V. Subba Rao, Roohi Irshad, S. Balakrishnan","doi":"10.1002/gj.5154","DOIUrl":"https://doi.org/10.1002/gj.5154","url":null,"abstract":"<div>\u0000 \u0000 <p>The Central Indian Tectonic Zone (CITZ) runs across peninsular India and includes Proterozoic bimodal volcanics (basalt-rhyolite), quartzite, mafic-ultramafic rocks, volcanic sediments and Banded Iron Formation (BIF). The bimodal volcanic rocks of Betul–Chhindwara belt have been subjected to upper greenschist to lower amphibolite-grade metamorphism and have well-preserved remnants of pillow structures. Total alkali vs. silica diagram clearly discriminates all the samples into subalkaline basalts and rhyolites which corresponds to their bimodal nature. Mafic volcanic sequence of Betul–Chhindwara belt is represented by high Ti and low Ti Groups. I. High Ti basalt has undergone low degree of partial melting (~5%), whereas low Ti basalt has undergone a high degree of partial melting (~20%) of the same source rock. Fe and Ca decrease with decreasing Ti indicating clinopyroxene and iron-titanium oxide fractionation in both the groups of basalt. These basalts are generally enriched in incompatible trace elements such as Rb and Ba and depleted in Nb, P and Ti, which collectively are good indicators of continental crust/lithosphere involvement in their genesis. The basalts show no Eu anomaly, which indicates little role of plagioclase during fractionation process. Positive anomalies of U–Th–Zr for the basalts indicate crustal involvement. Whole-rock Sm–Nd isochrons for the mafic volcanic rocks indicate an age of crystallisation for these volcanic rocks at about 1232 ± 37 Ma (initial <sup>143</sup>Nd/<sup>144</sup>Nd = 0.510752 ± 0.000035, mean square weighted deviate [MSWD] = 1.20) which is much younger than the basement rocks ca. 1500 Ma. The <i>ε</i>\u0000 <sub>Nd<i>t</i>\u0000 </sub> (<i>t</i> = 1232 Ma) vary from −5.93 to −3.1 for the mafic volcanic rocks and between −5.81 and +0.14 for felsic volcanic rocks. Depleted mantle model ages of basalts vary from 2204 to 3040 Ma, and for rhyolites, these vary from 2174 to 2863 Ma, respectively. The <i>ε</i>\u0000 <sub>Nd</sub> value for all the basaltic samples includes both the groups of basalts plot away from the CHUR line indicating their derivation from a depleted source and evolves to lower values, indicating longer crustal residence or more crustal contribution. Mafic magma might have been produced at the subduction zone interacted with the lower continental crust while ascending to the surface. This lowered the melting point of the continental crust which led to the production of felsic melt. Episodic mafic magma could have led to the production of rhyolite, produced at different levels of the continental crust.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1701-1720"},"PeriodicalIF":1.4,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study on the Physical, Chemical and Radioactive Gas—Radon (222Rn) Exhalation Properties of Bleached Sandstone in the Northeast Edge of the Ordos Basin","authors":"Xin Hu, Qiang Sun, Jiakun Wu, Shaoni Wei, Beichen Du, Xiaoying Ding, Jishi Geng","doi":"10.1002/gj.5157","DOIUrl":"https://doi.org/10.1002/gj.5157","url":null,"abstract":"<div>\u0000 \u0000 <p>The northeast margin of Ordos Basin, China has a large area with ‘bleached sandstone’, a unique rock characterised by a low diagenetic degree and poor cementation degree. Long-term wind and hydraulic erosion have led to significant soil erosion, vegetation degradation and low ecological carrying capacity in this region, with huge amounts of sediments being transported to the Yellow River. Therefore, it is critical to investigate the weathering mechanism and physicochemical characteristics of bleached sandstone. In this study, the pore structure, elemental composition, mineral composition and radon exhalation characteristics of the bleached sandstone were analysed using low-temperature nitrogen adsorption instrument, inductively coupled plasma mass spectrometer, polarising microscope and environmental radon detector, respectively. Moreover, the physicochemical characteristics of the bleached sandstone were analysed to determine the correlation among them. The results demonstrated that the degree of pore development in bleached sandstone is significantly higher than that in original rock, and the content of mesopores of size from 2 to 50 nm is the highest. These pores were found to be predominantly slit pores with parallel plate structure. The mineral composition is primarily quartz, feldspar, clay minerals and muscovite, with quartz being the highest. Quartz and feldspar exhibited significant weathering, broken crystals and more impurities. A large amount of biotite was altered to form muscovite. The intergranular spaces of bleached sandstone are filled with heterobase, primarily composed of clay minerals. Additionally, clay minerals formed a ring band structure around the particle skeleton. Bleached sandstone was found to be rich in P, Ba, Mn, Sr, Zr and other elements, with Ba showing the highest proportion. The bleached sandstone is enriched in toxic elements Be, As, Cd, Sb, Hg, Tl and <sup>238</sup>U compared with the original rock, indicating that the latter has a certain degree of adsorption. Among them, Be has the highest enrichment degree. Moreover, it is enriched with light rare earth and deficient in heavy rare earth. δEu and δCe exhibit a slight deficiency. Although the rate of radon exhalation in bleached sandstone is low, it is higher than that of the original rock. The high porosity and micropore content can promote radon exhalation. High <sup>238</sup>U content can enhance radon generation, which exhibited a positive correlation with radon exhalation rate. The research results can provide a reference for ecological management, development and utilisation of bleached sandstone in this region.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1736-1753"},"PeriodicalIF":1.4,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Driving Mechanism of Synergistic Efficiency in Reducing Pollution and Carbon: Evidence From 249 Green Parks","authors":"Chuang Li, Keke Li, Liping Wang","doi":"10.1002/gj.5133","DOIUrl":"https://doi.org/10.1002/gj.5133","url":null,"abstract":"<div>\u0000 \u0000 <p>The green park serves as a significant spatial carrier for China's strategy to become a manufacturing powerhouse and promote industrial transformation and upgrading. It is a crucial platform for implementing and driving the transformation and development of green manufacturing, promoting green development and harmonious coexistence between man and nature in the current era. The main focus of this study is a total of 249 green parks announced by the Ministry of Industry and Information Technology, and it employs the multi-time point PSM-DID method to investigate 280 prefecture-level cities. The results show that: (1) The coefficient of the green park certification policy is estimated to have a significantly negative impact at the 1% significance level. (2) The green park certification facilitates the integration of pollution reduction and carbon reduction efforts by leveraging green technology innovation and government support. (3) The promoting effect of green industrial park certification has regional consistency and resource heterogeneity. Therefore, it is of great significance to study the effects and pathways of green park certification on the synergies of carbon and pollution reduction.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1431-1452"},"PeriodicalIF":1.4,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Pang, Yonghe Sun, Ming Hu, Tongwen Sun, Shangming Shi
{"title":"Multiple Sets of Unconformity Migration Capacity and Their Influence on Hydrocarbon Accumulation in the Bozhong Area of the Bohai Bay Basin","authors":"Lei Pang, Yonghe Sun, Ming Hu, Tongwen Sun, Shangming Shi","doi":"10.1002/gj.5129","DOIUrl":"https://doi.org/10.1002/gj.5129","url":null,"abstract":"<div>\u0000 \u0000 <p>The Bohai Bay Basin is one of China's largest basins in terms of discovered hydrocarbon reserves. In this basin, unconformities serve as key pathways for the lateral migration of hydrocarbons, with the T8, T5 and T2 unconformities being the main ones developed here. Studying how these three unconformities differ in migration capacity is therefore essential for understanding hydrocarbon accumulation. By using logging data, along with measurements of porosity, permeability and sedimentary facies distribution, we analysed and compared the structures, physical properties and continuity of these unconformities. Based on this analysis, we linked hydrocarbon reserves per unit area to migration probability and developed a model for migration range. The results show that: (1) Although the T8 unconformity has poorer porosity and permeability compared to T5, it provides better continuity for migration channels, making T8 the main pathway in depressions, while T5 is more discontinuous and thus likely to form lithologic reservoirs in these areas. (2) T8 and T5 overlap gradually along the uplift belts, where both the porosity-permeability and thickness of these unconformities improve, and T2 has both good continuity and physical properties, facilitating lateral migration on the uplift belts. (3) Compared with other unconformities, T2 is the primary migration pathway above the uplift areas.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1394-1408"},"PeriodicalIF":1.4,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Apurva D. Shitole, Satish J. Patel, Jehova Lalmalsawm Darngawn, Jaquilin K. Joseph
{"title":"A Review of the Cretaceous Ichnology of Tethys-Related Basins in India: New Record From the Bagh Group","authors":"Apurva D. Shitole, Satish J. Patel, Jehova Lalmalsawm Darngawn, Jaquilin K. Joseph","doi":"10.1002/gj.5139","DOIUrl":"https://doi.org/10.1002/gj.5139","url":null,"abstract":"<div>\u0000 \u0000 <p>The Narmada Basin in west-central India forms the northern part of the Central Indian Tectonic Zone (CITZ). The Cretaceous Bagh Group rocks of the Western Lower Narmada Valley (WLNV) succession was studied for sedimentary facies analysis and ichnology. Textural and mineralogical characteristics along with primary and secondary sedimentary structures revealed 11 lithofacies, of which the calcareous sandstone, fine-grained sandstone-siltstone-shale and sandy/silty allochemic limestone lithofacies are highly bioturbated. WLNV contains a well-preserved, less diverse, and relatively abundant ichnofauna; a total of 24 ichnospecies belonging to 15 ichnogenera with pseudotrace fossils are identified and described. The trace fossils belong to the <i>Skolithos</i>, <i>Cruziana</i> and <i>Glossifungites</i> Ichnofacies. The <i>Skolithos</i> Ichnofacies suggest an upper shoreface environment with moderate-to-high energy conditions and shifting substrate; the <i>Cruziana</i> Ichnofacies suggest a lower shoreface environment with low-to-moderate sedimentation rates and energy conditions and the <i>Glossifungites</i> Ichnofacies suggest dewatering of sediments and a slow rate of sedimentation. Early ichnological studies in the different Tethys-related Cretaceous basins of the Indian subcontinent (Eastern Lower Narmada Valley, Kachchh, Cauvery, Jaisalmer, Barmer and Saurashtra) primarily focused on identifying the trace fossils, describing the new species and interpreting them in relation to trace producers and depositional environment. However, many of the ichnogenera and ichnospecies established from these basins need special attention because they either have been described as invalid, revised or assigned an unclear taxonomic status. The Cretaceous trace fossils reported to date from these basins are compiled along with their paleoenvironmental interpretation. The study also discusses the present status of the ichnogenera and ichnospecies names of the trace fossils reported to date from these basins. These data can be further used to enhance our understanding of how paleoenvironmental conditions control the distribution of trace-making communities across space and time.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1488-1514"},"PeriodicalIF":1.4,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Famanta Mahamane, Abid Ali Randhawa, Bilal Hussain, Javkhaa Tumennast, Abdelmohsen A. Nassani, Jamiatun Br Hombing, Cosimo Magazzino
{"title":"Exploring the Impact of Ecological Degradation on the Green Development Efficiency: An Empirical Analysis Using the Novel Epsilon-Based Measure and Global Malmquist–Luenberger Index","authors":"Famanta Mahamane, Abid Ali Randhawa, Bilal Hussain, Javkhaa Tumennast, Abdelmohsen A. Nassani, Jamiatun Br Hombing, Cosimo Magazzino","doi":"10.1002/gj.5136","DOIUrl":"https://doi.org/10.1002/gj.5136","url":null,"abstract":"<div>\u0000 \u0000 <p>The profound consequences of ecological degradation on humanity's well-being are a severe matter acknowledged globally. This study examines the impact of ecological degradation on green development efficiency in less developed countries. A dataset from 1990 to 2020 was used to break down the impacts of ecological degradation on green development efficiency. Green development efficiency was calculated based on the epsilon-based measure model, while the dynamic change of green development efficiency was explored with the Global Malmquist-Luenberger Index model. The panel-corrected standard errors (PCSE) and feasible generalised least squares (FGLS) models are conducted to test the influence of ecological degradation on green development efficiency. The results show that ecological degradation inhibits green development efficiency, whereas green FDI, urbanisation, and economic growth benefit the increase of green development efficiency. In addition, government intervention shows a negative correlation with green development efficiency. The results of the spatial Durbin model (SDM) of green development efficiency also demonstrate an overall strong negative spatial spillover effect on local and neighbouring regions, with more significant effects at levels of the surroundings.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 6","pages":"1453-1473"},"PeriodicalIF":1.4,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. L. Dharmapriya, W. M. R. Jayathilake, Lei Zhao, Pahan Abewardana, R. Kleinschrodt, N. D. Subasinghe
{"title":"Unravelling the Tectonic Nature of Charnockites Across the Highland and Wanni Complexes in Northeastern Sri Lanka: Implications for Demarcating Their Uncertain Lithotectonic Boundary","authors":"P. L. Dharmapriya, W. M. R. Jayathilake, Lei Zhao, Pahan Abewardana, R. Kleinschrodt, N. D. Subasinghe","doi":"10.1002/gj.5147","DOIUrl":"https://doi.org/10.1002/gj.5147","url":null,"abstract":"<div>\u0000 \u0000 <p>The tectonic evolution of terranes and microblocks is crucial for understanding the supercontinental cycle. Sri Lanka, centrally located between East and West Gondwana, offers insights into late Neoproterozoic continental tectonics. Ambiguities in defining boundaries between the Highland Complex (HC) and Wanni Complex (WC) of Sri Lanka prompted this study. Utilising whole-rock major and trace element geochemistry, and U–Pb zircon geochronology, we explore charnockites at the inferred HC-WC boundary, revealing their tectonic nature. Charnockites on the WC side (CWCs) display tholeiitic trends, characterised as Fe-rich, metaluminous A2-type granites. Tectonic discrimination diagrams position CWCs in the within-plate granite field. The <sup>238</sup>U/<sup>206</sup>Pb zircon geochronology of three WC-side charnockites gave Late Neoproterozoic metamorphic ages from 576 ± 37 to 561 ± 50 Ma and middle to early Neoproterozoic protolith crystallisation ages from 1011 ± 46 to 690 ± 15 Ma. Hence, protoliths of CWCs suggest some form of extensional tectonics in a continental environment during the early to middle Neoproterozoic that played a major role in the crustal evolution of the northeastern part of the WC. Out of the collected seven charnockites in the HC side (CHCs), three samples shared geochemical signatures resembling the CWCs. The <sup>206</sup>Pb/<sup>238</sup>U zircon ages of one of the samples yielded crystallisation age of ~780 ± 6 Ma and, metamorphic ages from 608 ± 9 to 541 ± 16 Ma, respectively. The rest of the CHCs exhibit calc-alkaline trend, identified as Mg-rich, metaluminous, I-type granites. Tectonic discrimination diagrams reveal volcanic arc signatures, indicating a subduction-related collisional tectonic setting. Geochemical and geochronological findings, coupled with field relations and prior research, lead to the interpretation that charnockites in the northeastern HC-WC boundary possess a distinctive geodynamic history, implying involvement in two distinct tectonic settings. Presently, at the erosion surface, the north-eastern portion of the HC-WC boundary, exhibits a highly diffused nature and manifests as a mixed rock zone.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 2","pages":"484-508"},"PeriodicalIF":1.4,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143439034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comprehensive Study and Evaluation of Significant Landslides Applying Geospatial and InSAR Coherence Techniques in Garhwal Himalaya, India","authors":"Soumik Saha, Biswajit Bera","doi":"10.1002/gj.5152","DOIUrl":"https://doi.org/10.1002/gj.5152","url":null,"abstract":"<div>\u0000 \u0000 <p>Landslides are the common geo-environmental hazard in Himalayan terrain. In the Indian Himalayan terrain, landslide-related hazards have intensified in the past few decades as a result of human intervention in the geomorphological and geological equilibrium conditions. This paper investigates the occurrences and their associated factors (geomorphological, geological, human-related factors) and presents a complete geomorphological mapping of four selected landslides, i.e., landslide near the Budhakedar region (landslide-1/L1), landslide near the Saund region (landslide-2/L2), Sirobagad landslide zone (landslide-3/L3) and Rampur landslide near Sonprayag (landslide-4/L4). These slides are mainly reactivated landslides, which become active during the monsoon period. Rock strength analysis (using rebound values from a standard N-type Schmidt hammer) shows that the rebound value is around 30 in most of the cases, but in the case of landslide 2, the intact rocks have a rebound value near about 60–65. Landslides 1, 3 and 4 are rock-cum-debris slides dominated by gneiss-schist, phyllite and quartzite types of rock, respectively, and landslide 2 is mainly a rock slide. The grain size test shows that the soil is poorly graded, which is composed of gravel and sand in every case. In the case of slide 2 (rockslide), the soil is classified as gravelly soil. The landslide activeness has been detected based on interferometric coherence change detection analysis using single look complex (SLC) sentinel 1A imageries (pre-monsoon and post-monsoon). The coherence results enable us to detect surface deformation over time. The result based on the InSAR coherence technique also stipulated the surface deformation or reactivation of the slides after the effect of rainfall.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"60 7","pages":"1682-1700"},"PeriodicalIF":1.4,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}