Evolving Earth最新文献

{"title":"Machine learning & geospatial approach for analysing the groundwater quality of J&K region, NW Himalaya","authors":"Avtar Singh Jasrotia ,&nbsp;Amit Sharma ,&nbsp;Mohinder Lal Angurala ,&nbsp;Komal Kumar Singh ,&nbsp;Upasna Andotra ,&nbsp;Rajesh Kumar","doi":"10.1016/j.eve.2026.100118","DOIUrl":"10.1016/j.eve.2026.100118","url":null,"abstract":"<div><div>The hydrochemical characteristics of groundwater in the Jammu &amp; Kashmir (J&amp;K) region were investigated using integrated machine learning and geospatial approaches. The major groundwater cations (Ca²⁺, Mg²⁺, Na⁺, K⁺) and anions (HCO₃⁻, SO₄²⁻, Cl⁻, NO₃⁻) were analysed. The ionic dominance followed the order Na⁺ &gt; Ca²⁺ &gt; Mg²⁺ &gt; K⁺ and HCO₃⁻ &gt; SO₄²⁻ &gt; Cl⁻ &gt; NO₃⁻. Total dissolved solids ranged from 4 to 2555 mg L⁻¹ (mean: 332.74 mg L⁻¹), while electrical conductivity varied between 150 and 4820 μS cm⁻¹. Gibbs and Piper diagrams indicate that groundwater chemistry is primarily governed by carbonate and silicate weathering processes, with silicate weathering contributing significantly to Na⁺ enrichment. Water Quality Index (WQI) values ranged from 23.11 to 429.23, classifying 85% of samples as excellent to good for drinking, while 22% were identified as poor to unsuitable. Statistical analysis revealed non-normal distribution of all variables (Shapiro–Wilk test), and Spearman's rank correlation indicated significant interrelationships among major ions. Machine learning models- Artificial Neural Network (ANN), Support Vector Regression (SVR), and Random Forest (RF) were applied for WQI prediction, with SVR outperforming other models (R² = 0.99, MSE = 15.51) and achieving an overall prediction accuracy of approximately 80%. The results demonstrate that coupling hydrochemical process interpretation with machine learning–based prediction provides a scalable and transferable framework for regional groundwater quality assessment across data-rich Himalayan terrains.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100118"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396954","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}

{"title":"Streptichnus ichnofossils from the Marwar Supergroup: Tracing early Cambrian shallow-marine ecosystems","authors":"S. Ahmad","doi":"10.1016/j.eve.2025.100102","DOIUrl":"10.1016/j.eve.2025.100102","url":null,"abstract":"<div><div>The ichnogenus <em>Streptichnus</em> is a key component of Early Cambrian ichnofaunas, reflecting the increasing complexity of benthic behavior and animal substrate interactions during this evolutionary interval. In the Cambrian Nagaur Sandstone (Marwar Supergroup) of western India, <em>Streptichnus</em> occurs abundantly within shallow-marine siliciclastic facies, providing important evidence for the nature of the Early Cambrian biosphere in the Indian subcontinent. In this study, <em>Streptichnus</em> burrows from the Nagaur Sandstone, Marwar Supergroup are described and compared with occurrences from the Shibantan Member of the Dengying Formation in South China. Their morphology, distribution, and global significance highlight the role of tracemakers in substrate destabilization and ecospace expansion during the Early Cambrian.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100102"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841678","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}

{"title":"Source terranes, humid-weathering diagenesis, and fluvial deposition in the cretaceous Garoua Basin: Implications for correlation with the upper Benue (Bima) system","authors":"Hermann Nyochembeng Akateh ,&nbsp;Olugbenga A. Boboye ,&nbsp;Edwin Ayuk Ndip ,&nbsp;Shivanjali Sharma ,&nbsp;Darshan Halari ,&nbsp;Andre Mbabi Bitchong ,&nbsp;Raoul Gake Belle","doi":"10.1016/j.eve.2026.100109","DOIUrl":"10.1016/j.eve.2026.100109","url":null,"abstract":"<div><div>The Cretaceous Garoua Rift Basin, an eastern extension of the Upper Benue Basin in West Africa, preserves a fluvial succession essential for understanding the syn-rift sediment deposition of the West and Central African Rift System (WCARS). This study provides a comprehensive analysis of the clastic fill of the basin, combining grain size statistics, thin section petrology, heavy-mineral analysis, X-ray diffraction, and scanning electron microscopy to elucidate the provenance, diagenesis, and depositional processes. The results reveal that the sediments consist primarily of medium-to coarse-grained, moderately to moderately well-sorted, arkose to subarkose, characterized by approximately leptokurtic and near-symmetrical grain size distributions. These textural attributes indicate deposition by bedload-dominated, braided to low-sinuosity fluvial systems under high-energy conditions. The signatures of provenance, characterised by a framework dominated by quartz, feldspar and a group of heavy minerals abundant in zircon, tourmaline and rutile (ZTR) alongside prominent garnet and staurolite (GZi = 23–59 %), clearly indicate a source from nearly granitoid and gneissic basement rock throughout Pan-African. Diagenesis was primarily influenced by humid-weathering processes, as evidenced by the high kaolinite content of feldspar (up to 43 wt%) and widespread hematite cementation, which together governed the development of the reservoir quality. The striking similarity in composition, texture, and diagenetic overprint between the Garoua Succession and the upper Bima Member of the Nigerian Benue Trough confirm their stratigraphic equivalence. This correlation defines a coherent Cretaceous river system within the Yola-Garoua rift arm, providing an improved model for source-to-basin dynamics and reservoir characterisation in humid climate rift basins.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100109"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078513","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}

{"title":"Subsidence and sea-level controls on the evolution of a mixed siliciclastic-carbonate platform: the eastern margin of New Caledonia (SW Pacific)","authors":"Léa Kerouedan ,&nbsp;Pascal Le Roy ,&nbsp;Gwenael Jouet ,&nbsp;Estelle Leroux ,&nbsp;Stephan J. Jorry ,&nbsp;Elsa Tournadour ,&nbsp;Martin Patriat ,&nbsp;Axel Ehrhold ,&nbsp;Samuel Etienne ,&nbsp;Agathe Ignacio ,&nbsp;Valentin Ferelloc","doi":"10.1016/j.eve.2026.100120","DOIUrl":"10.1016/j.eve.2026.100120","url":null,"abstract":"<div><div>The island of Grande-Terre in New Caledonia (NC) hosts one of the world's largest lagoon complexes, and its sediment infill makes it an ideal case study to understand the evolution of mixed siliciclastic-carbonate platforms. The under-researched eastern margin of Grande-Terre provides an opportunity to examine the major changes in lagoon sedimentation since the end of the Mio-Pliocene in response to climate variation, vertical movements and anthropogenic activities. Using geomorphological and seismic interpretations constrained with dated sediment cores, this study identifies three seismic sequences separated by major channelized and erosional unconformities. The upper and last unconformity is supposed to be linked to the sea-level lowstand during the Last Glacial Maximum. The overlying sedimentary record, dated to the Holocene, contains both clastic and carbonate deposits, resulting from the reflooding of the shelf. This mixed sediment infill displays significant spatial variation. The inner lagoon concentrates terrigenous inputs whereas the median lagoon is dominated by a series of large carbonate reef flats. The outer shelf preserves a remarkable succession of falling-stages deposits that reflect 100 kyr depositional sequence cycles resting atop the Mio-Pliocene carbonate platform. Stratigraphic analysis of these Pleistocene sequences dates their deposition from 630 kyr (MIS 16) and allows us to estimate a subsidence rate of approximately 0.06 m/kyr on the outer shelf, enabling the barrier reef to keep up and the successive lowstand sediment wedges to stack.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100120"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709601","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}

{"title":"Groundwater potential zonation in a tropical hard-rock basin, South India: An evidence-based approach","authors":"M.C. Raicy ,&nbsp;C.D. Aju ,&nbsp;A.L. Achu ,&nbsp;P. Mohammed Maharoof ,&nbsp;A. Ashwin","doi":"10.1016/j.eve.2026.100121","DOIUrl":"10.1016/j.eve.2026.100121","url":null,"abstract":"<div><div>Groundwater potential zonation is a crucial tool for identifying regions with varying groundwater availability, and for integrating geological, hydrological, and environmental factors. This study evaluates the groundwater potential of Kadalundi River Basin (KRB) in northern Kerala, India, using the Analytic Hierarchy Process (AHP) and Geographic Information System (GIS) techniques, and validates the results with subsurface geophysical signatures and well-yield data. Key geo-environmental variables, including geology, geomorphology, groundwater level fluctuations (GWLF), lineament density, land use/land cover (LU/LC), slope, soil texture, rainfall, topographic wetness index (TWI), terrain curvature, and topographic position index (TPI), were analyzed for their influence on groundwater occurrence. Based on the study, the groundwater potential zones in KRB were classified as very poor, poor, moderate, high, and very high, covering approximately 20.0%, 19.7%, 19.8%, 20.3%, and 20.2% of the basin, respectively, with high and very high zones concentrated mainly in the southeastern and western areas. Lithology emerged as the most influential controlling factor, followed by geomorphology. The reliability of the zonation was assessed using a two-fold validation based on VES (Vertical Electrical Sounding) and observed well-yield data. The predicted index showed strong agreement with well yield (R² = 0.877). The spatial variability of groundwater potential across KRB provides valuable insights for sustainable groundwater management. The study provides a reliable background for groundwater potential assessment in similar hydrogeological settings and supports informed decision-making for water resource planning in the region.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100121"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709612","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}

{"title":"Multi–parametric approach using SAR data for Siachen glacier dynamics in the Karakoram Himalaya","authors":"Ajay Kumar Taloor ,&nbsp;Akash Basotra ,&nbsp;Shiwalika Sambyal ,&nbsp;Gurnam Parsad ,&nbsp;Kanika Sharma ,&nbsp;Purushottam Kumar Garg ,&nbsp;Sushil Kumar Singh ,&nbsp;Ashutosh Tiwari ,&nbsp;Meenakshi Sharma","doi":"10.1016/j.eve.2026.100117","DOIUrl":"10.1016/j.eve.2026.100117","url":null,"abstract":"<div><div>The study focuses on the Siachen Glacier and uses Sentinel-1A Synthetic Aperture Radar (SAR) data between 2017 and 2024 to explore glacier dynamics, i.e., glacier mass balance (GMb), equilibrium line altitude (ELA), facies classification, and surface velocity. High-level SAR pre-processing techniques, e.g., application of orbit files, thermal noise removal, calibration, and terrain correction, were carried out by using the Sentinel Application Platform (SNAP). Four zones—Frozen Percolation Zone (FPZ), Wet Snow Zone (WSZ), Bare Ice Zone (BIZ), and Debris-Covered Ice Zone (DCIZ)—were inferred for glacier facies using backscatter thresholds derived from VV and VH polarizations. Dynamic distribution of facies is captured in the results with significant fluctuation in the WSZ, general decrease in the BIZ, changing debris coverage in the DCIZ, and a constant FPZ. The average ELA was 5612.48 ± 203.2 m, and the average GMb was −0.668 ± 0.2 meter water equivalent ( m w.e. y⁻¹), showing sustained loss of ice mass dominated by climatic variability, a pattern observed in most Himalayan glaciers. Glacier retreat and variation in GMb have been linked to variation in climatic conditions, which has resulted in sustained loss of ice over the years. Surface velocity analysis revealed values ranging from 5.04 to 133.64 ± 2.3 m y⁻¹, with maximum velocities observed in the year 2023, indicating periods of dynamically enhanced glacier flow. Overall, the study demonstrates the effectiveness of multi-temporal SAR data for long-term, weather-independent monitoring of glacier facies, GMb, and flow dynamics in the Karakoram Himalaya.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100117"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147538869","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}

{"title":"Neotropical plant species produce charcoal particles distinguishable by morphometrics and morphotypes","authors":"Daniel Kroehling ,&nbsp;José João Lelis Leal de Souza ,&nbsp;Joel Maciel Pereira Cordeiro ,&nbsp;Nedret Billor ,&nbsp;Alexandra Tsalickis ,&nbsp;Bartolomeu Israel de Souza ,&nbsp;Curtis J. Hansen ,&nbsp;Leslie R. Goertzen ,&nbsp;Julie C. Aleman ,&nbsp;Richard S. Vachula","doi":"10.1016/j.eve.2026.100130","DOIUrl":"10.1016/j.eve.2026.100130","url":null,"abstract":"<div><div>Sedimentary charcoal analysis is a popular method to infer fuel sources and reconstruct paleofire and paleoecological history. However, existing proxy calibration experiments are concentrated on Palearctic and Nearctic floras, leaving tropical ecosystems understudied. To address this knowledge gap, we experimentally burned 21 Neotropical plant taxa and characterized charcoal morphology across tissues (leaf, wood, bark, stem) and growth habits (tree, shrub, liana, herb). We found that charcoal morphology is partitioned by tissue type: leaf tissues are significantly distinct from all others, yielding more circular and irregular particles, while wood and bark generate highly elongated particles. Notably, shrub wood produced charcoal with the highest mean length-to-width (L:W) ratios reported to date. Growth habits were also statistically distinguishable, with shrub and tree wood forming more elongated charcoal than lianas and herbs. We infer that these exceptionally high L:W values reflect ecophysiological adaptations to seasonal drought in Neotropical arboreal wood, which burns and fractures along elongated vessels and thick-walled fibers. Additionally, circularity emerged as a complementary morphometric for discriminating shape differences. Our results demonstrate a greater biogeographic heterogeneity of charcoal morphometrics than previously recognized, expanding the global reference dataset, and giving important methodological insights for future paleofire studies in the Neotropics.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100130"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147746000","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}

{"title":"Enhancing paleoclimate reconstructions in the late Aptian North-Northeast Brazil using clay mineralogy","authors":"Victor Matheus Joaquim Salgado-Campos ,&nbsp;Luiz Carlos Bertolino ,&nbsp;Leonardo Borghi ,&nbsp;Aristóteles de Moraes Rios-Netto ,&nbsp;Bruno Cesar Araújo ,&nbsp;Danielle Cardoso de Souza ,&nbsp;Laís de Oliveira Ferreira ,&nbsp;Fabia Emanuela Rafaloski Bobco ,&nbsp;Jéssica de Souza Gabi Barcellos ,&nbsp;Ismar de Souza Carvalho","doi":"10.1016/j.eve.2026.100111","DOIUrl":"10.1016/j.eve.2026.100111","url":null,"abstract":"<div><div>Paleoclimate changes are commonly analyzed on three distinct scales: small-scale (20–500 kyr), linked to Milankovitch cycles; medium-scale events (∼30 Myr), associated with sea-level changes and tectonic activity; and large-scale (∼300 Myr), related to icehouse-greenhouse transitions. Different methods are used in paleoclimatology, with clay mineralogy emerging as a particularly effective tool. This study presents an approach to understanding late Aptian paleoclimate variations in North-Northeastern Brazil using clay mineralogy. To achieve this, fifty-two mudrock samples from the late Aptian Codó and Itapecuru formations were analyzed in the Parnaíba Basin (Northeastern Brazil) using clay and bulk mineralogy, major element chemical analysis, and scanning electron microscopy. These new data were integrated with a compiled dataset and evaluated using climofunctions to reconstruct paleoprecipitation and paleotemperature conditions, which were subsequently compared with patterns observed in modern lacustrine environments. Three paleoclimate stages were identified in North-Northeastern Brazil during the late Aptian, characterized by four distinct clay mineral assemblages. From the older to the younger stages, the first one indicates paleoprecipitation values ranging from 800 to 1000 mm/yr and paleotemperatures of approximately 15 °C. The second stage indicates paleoprecipitation values of up to 200 mm/yr and paleotemperature values of approximately 22 °C. The third stage suggests paleoprecipitation values between 600 and 800 mm/yr and paleotemperature conditions of approximately 20 °C. These paleoclimate stages indicate an aridification followed by a humidification process during the late Aptian in North-Northeastern Brazil. The latter humidification is likely linked to the Gondwana break-up and the potential onset of Oceanic Anoxic Event 1b, which marks the transition from the Aptian to the Albian. This study contributes to the use of clay minerals in reconstructing past climates and enhances our understanding of late Aptian climate changes in North-Northeastern Brazil.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100111"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078510","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}

{"title":"Comparative assessment of seasonal dynamics in water characteristics of Salim Ali Lake and Harsul Lake in Chhatrapati Sambhajinagar, Maharashtra, India","authors":"Prasanna Lavhale,&nbsp;Pranaya Diwate,&nbsp;Praful Shinde","doi":"10.1016/j.eve.2025.100101","DOIUrl":"10.1016/j.eve.2025.100101","url":null,"abstract":"<div><div>Lakes are inland water bodies serving as a freshwater resource. They are critical resources that sustain ecological balance and support human beings. Present study was carried out to assess the level of contamination of two lakes situated in the Chhatrapati Sambhajinagar city. Water samples from the Salim Ali Lake and the Harsul Lake were collected in the year 2024 across four seasons. Physicochemical and heavy metal analysis were carried out in the laboratory using rapid water testing kit to find out the level of contamination. Water Quality Index (WQI), Coefficient of Variation (CV), Nemerow Pollution Index (NPI) and Pearson Correlation were derived. An evaluation of NPI revealed that, during Winter season the Harsul Lake has NPI value 0.99 indicating substantial pollution while the Salim Ali Lake has NPI value 1.17 exhibiting heavy pollution. During Premonsoon season, observed NPI values of the Salim Ali Lake and the Harsul Lake were 1.07 and 0.83 respectively suggesting heavy pollution and moderate level of pollution respectively. In the Monsoon season, observed NPI values were 1.38 and 1.14 of the Salim Ali Lake and the Harsul Lake respectively which clearly depicted the higher level of pollution. The NPI value during Postmonsoon season slightly increases of both the lakes. The observed NPI value of the Salim Ali Lake and the Harsul Lake was 1.39 and 1.12 respectively indicating both lakes are heavily polluted. Overall analysis revealed that, the Salim Ali Lake is more polluted than the Harsul Lake. It might be due to the Salim Ali Lake is situated in central part of city while the Harsul Lake is situated at outskirt of the city. The spatial analysis carried out and Watershed delineation and land use land cover map were prepared using ArcGIS 10.8 software. Shuttle Radar Topography Mission – Digital Elevation Model data were utilized for preparing the watershed delineation map and Sentinel – 2 satellite imagery were used for the land use land cover classification of watershed. The present study helps policymakers to understand the current state of lake, allowing them to develop new policies accordingly. The water quality index emphasizes the urgent need of implementing pollution controlling strategies to stop further disintegration of the both the lakes.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100101"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760840","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}

{"title":"Understanding provenance, tectonic settings and diagenetic changes of Upper Disang (Middle to late Eocene) sandstones of Phek District, Nagaland (India): insights from petrography and heavy mineral assemblages","authors":"S.K. Srivastava ,&nbsp;A. Patra ,&nbsp;K. Swuro ,&nbsp;V. Kirha ,&nbsp;S. Kanhaiya","doi":"10.1016/j.eve.2026.100128","DOIUrl":"10.1016/j.eve.2026.100128","url":null,"abstract":"<div><div>The Upper Disang (Middle to Late Eocene) sandstones exposed in the Phek District of Nagaland were investigated using integrated petrographic and heavy mineral analysis to constrain their provenance, tectonic setting, and diagenetic evolution. The sandstones are light to dark grey in colour and are composed predominantly of very fine to fine grained sand fractions. Petrographic examination indicates that quartz is the dominant framework component, occurring mainly as angular to sub-angular grains with occasional sub-rounded forms. Both orthoclase and plagioclase feldspars are present, while lithic fragments constitute the next most abundant framework component and include sedimentary, metamorphic, and volcanic rock fragments. The heavy mineral assemblage is characterized by sub-angular to sub-rounded grains of zircon, tourmaline, rutile, kyanite, sillimanite, hypersthenes and opaque minerals. Detrital modal compositions plotted on Q–F–L diagrams indicate a dominant recycled orogen provenance, with contributions consistent with a passive margin tectonic setting. The combined framework grain composition and heavy mineral suite suggest a mixed provenance, reflecting sediment supply from multiple source terrains influenced by the complex tectonic framework of the region. Tectonic activity also played a significant role in drainage reorganization, facilitating sediment input from diverse directions and source areas. Diagenetic features preserved in the Upper Disang sandstones indicate predominance of shallow burial diagenesis, with localized signatures of early mesodiagenesis developed at burial depths of approximately 3–5 km and temperatures exceeding 150 °C. The integrated provenance and diagenetic signatures provide important insights into the tectono-sedimentary evolution of the Upper Disang Formation within the Indo–Myanmar orogenic system.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100128"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709448","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}