Evolving Earth最新文献

{"title":"A middle Eocene hydrocarbon-seep fauna from Ecuador and the lost ecologic niche of large, high-spired gastropods at seeps","authors":"Steffen Kiel ,&nbsp;Ronald C. Eng ,&nbsp;Michael A. Rich ,&nbsp;James L. Goedert","doi":"10.1016/j.eve.2026.100150","DOIUrl":"10.1016/j.eve.2026.100150","url":null,"abstract":"<div><div>Middle Eocene (Bartonian) carbonate rocks found at Punta Ancón in southwestern Ecuador are here identified as an ancient hydrocarbon seep deposit based on its negative δ¹³C signature (as low as −32.4‰). The fauna includes members of the bivalve families Thyasiridae, Lucinidae, and Kalenteridae, and the abyssochrysoid gastropod <em>Ascheria elenensis</em>, which reached an estimated height of 150 mm or more. Such large, high-spired gastropods occurred at Cretaceous through mid-Eocene seeps worldwide but are notably absent today. This geologic range coincides with a period of particularly low marine sulfate concentrations. We discuss the lost ecologic niche of these large, high-spired gastropods and favor an interpretation of them as having been grazers on microbial mats, potentially composed of different kinds of bacteria than those forming mats at modern seeps. As a considerable proportion of the Punta Ancón seep fauna was obligate to this environment, the depositional depth of this site can be described as offshore.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100150"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148241236","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":"Geochemical assessment of supergene manganese ores occurrence from weathering crust of the Lower Dja Series, East Cameroon","authors":"Ndema Mbongué Jean-Lavenir ,&nbsp;Moundignigni Amad Badawi ,&nbsp;Ngoran Gilles ,&nbsp;Lemnyuy Prosper Yiika ,&nbsp;Median Yongye ,&nbsp;Bafon Godlove ,&nbsp;Nchimenyi Sobse ,&nbsp;Peter Namange","doi":"10.1016/j.eve.2026.100144","DOIUrl":"10.1016/j.eve.2026.100144","url":null,"abstract":"<div><div>The Lower Dja Series hosts manganese ore minerals. XRD and whole-rock geochemistry were used to assess the geochemical characteristics of Mn ores. Supergene manganese ores develop in situ though weathering processes. Mn-rich rocks consist of massive coalescent blocks in laterite and free blocks of massive manganese oxide. Laterites are classified as ferruginized sediments, vermiform, and pisolitic suggesting different modes of evolution of laterites. Mn-rich rocks are composed of pyrolusite and hollandite, and classified as high- and low-grade Mn ore. High-grade Mn ores are enriched in manganese minerals and have high contents of Mn/Fe, MnO, Ba, Co, Pb, V, and are depleted in MgO, K₂O, P₂O₅, and Rb compared to low-grade Mn ores. Both high- and low-grade Mn ores show enrichment in high field strength elements, transitional metals, and rare earth elements (REEs). REE profiles reveal REE fractionation (La_N/Yb_N: 0.34–1.19 for high-grade Mn ore, 0.76–2.75 for low-grade), positive Eu (Eu/Eu∗: 1.06–1.54) and Ce (Ce/Ce∗: 1.27–2.24) anomalies, consistent with modern Fe-Mn nodules. This implies that the primary sedimentary Mn ore is generated by hydrogenetic activity and has undergone weathering process to form supergene Mn ore minerals in the Cenozoic era. The Supergene Mn occurrence of Bateka is similar to globally recorded deposits in Gabon, South Africa, Côte d’Ivoire, Ghana, Burkina Faso, Australia, Brazil, Ukraine, India, and China. The outcomes of the study not only shed light on the occurrence of manganese occurs, but also serve as a valuable roadmap for pinpointing host rocks and driving future exploration.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100144"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148184146","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":"Palynofloral and carbon isotopic patterns of an Early Cretaceous peat mire in Laurasia: Implications for regional short-versus long-term climate variability","authors":"Alexander Wheeler,&nbsp;Tim A. Moore,&nbsp;Jian Shen,&nbsp;Ofentse M. Moroeng","doi":"10.1016/j.eve.2026.100156","DOIUrl":"10.1016/j.eve.2026.100156","url":null,"abstract":"<div><div>The Early Cretaceous #14 and #15 coal seams of the Yimin Formation (Hailar Basin, Inner Mongolia, China) have been characterised using palynological and stable carbon isotopic analyses. These seams represent the stratigraphically highest (and thus youngest) Albian-aged coal seams studied in the region. The palynoflora is dominated by spore-producing pteridophytes (mainly ferns) alongside a community of mainly pinacean and cupressacean gymnosperms. Notably, no angiosperms were recorded. The lower part of the seam contains diverse pteridophyte assemblages reflecting an environment subject to periodic flooding, as evidenced by ash yield values. The middle section marks a shift from forested to a fern-dominated vegetation, forming a transitional to possibly domed mire under relatively stable tectonic and sedimentological conditions that favoured thick peat accumulation. In the uppermost part, floral diversity increases compared to the lower sections. The presence of lycophytes and bryophytes in the upper parts of the coal seam suggest wetter conditions prior to drowning of the palaeomire, which terminated peat deposition. These environmental shifts are further supported by both the ash yields as well as highly fluctuating stable carbon isotopic values in the lower part of the seam, with consistently lighter values occurring during wetter conditions. Although there are clearly shorter-term climatic conditions occurring over the span of a single palaeomire, data across a number of other studies in the Yimin Sag, and broadly in the Hailar Basin (and elsewhere), indicate that the climate has remained warm and predominantly humid for the previous 40 Ma.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100156"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148729663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A prognostic ichnofabric framework for the Ediacaran-Cambrian transition: Marwar Supergroup, India","authors":"S. Ahmad,&nbsp;S.K. Pandey","doi":"10.1016/j.eve.2026.100152","DOIUrl":"10.1016/j.eve.2026.100152","url":null,"abstract":"<div><div>The Ediacaran-Cambrian transition represents a fundamental reorganization of marine ecosystems, marked by the decline of matground-dominated substrates and the expansion of pervasive bioturbation. The transition records an emergent ecological phenomenon characterized by the rapid expansion of bioturbation and ecosystem engineering, likely driven by positive feedbacks between metazoan activity, substrate modification, nutrient recycling, and benthic habitat expansion. However, the environmental mechanisms driving this transformation remain insufficiently quantified, particularly in the Indian subcontinent. Here, we integrate sedimentological, ichnological, and chemostratigraphic data from the Marwar Supergroup (India) to investigate the environmental and ecological controls on ichnofabric development across the Ediacaran-Cambrian transition. The studied succession records a progressive increase in trace-fossil abundance, ichnodiversity, burrow complexity, and vertical tiering from the Jodhpur Group to the Bilara Group, accompanied by a marked decline in microbial sedimentary structures. These changes indicate a transition from matground-dominated ecosystems to increasingly complex mixground communities characterized by active sediment reworking and ecosystem engineering. A strong positive relationship between ichnofabric development (IPI) and δ¹³C values suggests that the expansion of benthic activity was closely linked to changes in carbon cycling and marine redox conditions. The Bilara Group represents a key transitional interval, recording enhanced carbonate deposition, intensified bioturbation, and intermediate ecological conditions between matground and fully developed mixground ecosystems. To quantify these trends, we introduce a semi-quantitative Ichnofabric Potential Index (IPI), derived from a multivariate approach incorporating bioturbation intensity, ichnodiversity, tiering, microbial structures, and δ¹³C values, to capture the combined influence of oxygenation, sedimentation rate, substrate consistency, and behavioural complexity. A logistic model further indicates that the transition from matground to mixground ecosystems follows a threshold response, with rapid expansion of bioturbation once critical environmental conditions are exceeded. These findings provide evidence for a threshold-driven ecological shift during the agronomic revolution and suggest that the rise of early ecosystem engineering in the Marwar Basin was strongly modulated by progressive environmental oxygenation and carbon cycle dynamics. The proposed framework provides a quantitative and transferable approach for evaluating early benthic ecosystem evolution.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100152"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148523400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking land use change to urban heat signatures: Multi-decadal analysis of Asansol municipality, India","authors":"Sudipta Mukherjee,&nbsp;Gargee Das,&nbsp;Sourajit Mal,&nbsp;Debasish Sing,&nbsp;Bikash Dutta,&nbsp;Manas Das","doi":"10.1016/j.eve.2026.100174","DOIUrl":"10.1016/j.eve.2026.100174","url":null,"abstract":"<div><div>Rapid urbanization, industrial expansion, and open-cast mining have fundamentally altered land use and land cover (LULC) in the Damodar Valley industrial corridor. Urban heat island (UHI) research typically treats surface warming as a function of impervious expansion, and rarely accounts for landscapes in which active and abandoned open-cast mining, spoil dumps, and reclaimed ground coexist with dense settlement. This study characterizes such a coupled mining–urban thermal regime in Asansol Municipality, India, using eight Landsat epochs from 1996 to 2024 and a scenario projection to 2050. A single-window retrieval was applied uniformly to Landsat 5 TM and Landsat 8/9 TIRS thermal bands, removing algorithm-related bias from the multi-decadal comparison. Supervised classification (per-epoch overall accuracy 80.70–99.83%), spectral indices (NDVI, NDWI, NDBI), an ANN–MLP cellular automata model (validated against the observed 2024 map: 94.96% correctness, Kappa 0.937), and Random Forest regression (CV RMSE 1.22 °C, R² 0.923) were employed. Within a municipal area of 197.20 km², settlement expanded almost fourfold, from 7.55 km² in 1996 to 28.37 km² in 2024, and is projected to reach 40.42 km² by 2050; agricultural land contracted from 68.25 km² to 24.24 km², while fallow land held the largest share of the municipality throughout, at 57.99 km² in 2024. Maximum LST peaked at 48.19 °C in 2004 and stood at 40.85 °C in 2024, indicating spatial reorganization rather than monotonic warming. The robust signal is a change in thermal control: the NDBI–LST correlation strengthened from r = 0.47 (1996) to r = 0.69 (2016) and remained high in 2024 (r = 0.57), while NDVI–LST and NDWI–LST weakened to r = −0.01 and r = −0.13, respectively. Surface temperature is therefore no longer buffered by vegetation and moisture but is instead governed by impervious, exposed surfaces. Class-wise analysis shows that open-cast mining and fallow land are consistently among the warmest cover types, with fallow land now the most extensive class in the municipality. This study underscores the urgent need for climate-sensitive land management, mine rehabilitation, urban greening, and integrated thermal risk planning in rapidly industrializing South Asian cities.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100174"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149252027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of high latitude fluvial system in a humid climate conditions (Maastrichtian–Danian, Magallanes Basin, Chilean Patagonia)","authors":"Leslie M.E. Manríquez ,&nbsp;Ernesto L.C. Lavina ,&nbsp;Juan Pablo Pino ,&nbsp;Cristine Trevisan ,&nbsp;Jhonatan Alarcón-Muñoz ,&nbsp;Joseline Manfroi ,&nbsp;Hector Mansilla ,&nbsp;Marcelo Leppe","doi":"10.1016/j.eve.2026.100124","DOIUrl":"10.1016/j.eve.2026.100124","url":null,"abstract":"<div><div>This study documents fluvial dynamics and paleoenvironmental evolution in a high-latitude foreland basin during the Maastrichtian–Danian, based on integrated sedimentological and paleontological analysis of a continental–coastal succession exposed in the Río de las Chinas Valley, Magallanes Basin, southern Chile. The fluvial record is characterized by sandy to gravelly channel bodies embedded within an extensive muddy floodplain, reflecting deposition on a low-gradient fluvial plain developed in the distal sector of the basin. Two main channel styles are recognized within the fluvial system: sinuous channels dominated by lateral-accretion point-bar deposits, and higher-energy braided channels composed of sandy to gravelly longitudinal bars. These channel styles occur laterally within the same fluvial corridor, indicating that channel morphology was primarily controlled by spatial variability in sediment supply and discharge rather than by downstream changes in slope or base level alone. Gravel-rich braided reaches are interpreted to reflect higher bedload input, whereas sandy sinuous channels developed in sectors dominated by suspended load. Dispersed paleocurrent patterns are interpreted as the result of channel migration and bar accretion processes within a low-gradient system, rather than evidence for independent drainage networks. Floodplain deposits record frequent overbank flooding, crevasse-splay activity, abandoned channels, and swampy environments, locally including deposits related to hyperconcentrated flows generated during high-magnitude floods under humid climatic conditions. Recurrent vertical and lateral intercalations of fluvial and shallow-marine facies indicate direct interaction between fluvial systems and a high-energy, linear coastline, emphasizing the role of accommodation changes linked to relative sea-level fluctuations at the end of the Cretaceous. Paleobotanical and taphonomic evidence supports humid conditions during the Maastrichtian, followed by a shift toward cooler and drier climates near the Cretaceous–Paleogene transition. Overall, the Río de las Chinas succession provides a well-exposed record of fluvial dynamics in a high-latitude foreland basin at the end of the Cretaceous.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"4 ","pages":"Article 100124"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709447","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":"Chaotic behaviour of the Earth System in the Anthropocene","authors":"A.E. Bernardini ,&nbsp;O. Bertolami ,&nbsp;F. Francisco","doi":"10.1016/j.eve.2025.100060","DOIUrl":"10.1016/j.eve.2025.100060","url":null,"abstract":"<div><div>It is shown that the Earth System (ES) can, due to the impact of human activities, behave in a chaotic fashion. Our arguments are based on the assumption that the ES can be described by a Landau–Ginzburg model, which on its own allows for predicting that the ES evolves, through regular trajectories in the phase space, towards a Hothouse Earth scenario for a finite amount of human-driven impact. Furthermore, we find that the equilibrium point for temperature fluctuations can exhibit bifurcations and a chaotic pattern if the human impact follows a logistic map. Our final analysis includes interactions between different terms of the planetary boundaries (PB) in order to gauge the predictability of our model.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100060"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Provenance, paleoweathering and maturity study of shales in the Mundeck Formation of Kribi-Campo sub-basin in the western African margin (A geochemical approach)","authors":"Ashukem Ethel Nkongho ,&nbsp;Bokanda Ekoko Eric ,&nbsp;Bisse Salomon Betrant ,&nbsp;Kwankam Florence Njinto ,&nbsp;Philip Fralick ,&nbsp;Ikose Franklin ,&nbsp;Nzesseu Valentino ,&nbsp;Belinga Belinga Cedric ,&nbsp;Ekomane Emile","doi":"10.1016/j.eve.2025.100084","DOIUrl":"10.1016/j.eve.2025.100084","url":null,"abstract":"<div><div>The geochemical investigation of shales from Mundeck Formation of the Kribi-Campo sub-basin was conducted to determine the origin, tectonic setting evolution, paleo-weathering conditions, sediment maturity and cycling. The research included a comprehensive field survey, sample collections, and analysis of a variety of major, trace, and rare-earth elements using inductive couple plasma-atomic emission spectrum (ICP-AES) and inductive couple plasma-mass spectrum (ICP-MS). Provenance plots of La/Sc, Th/Co, Cr/Th, Th/Sc ratios and Zr vs TiO₂, Al₂O₃vs TiO₂ disclosed a felsic to mixed rock composition as the source rock of the studied shales. The felsic to mixed source rock compositions are also supported by an enrichment of LREE/HREE and a negative europium anomaly on chondrite calculation and chondrite normalized diagram. Discriminant diagrams of DF(A-P)M, and DF(A-P)MT used, designate an active marginal source rock for the studied shales. The active margin signature in this work shows the source rocks of the study shales was affected by the tectono thermal events of the Pan African Orogeny also known as the Brasiliano orogeny in South America. The chemical index of alteration (CIA and CIX) and the plagioclase index of alteration (PIA and PIX) suggest weak to extreme intensity. These variations are cause by potassium enrichment and depletion during weathering. The old and new ICV calculated values suggest that the shales are immature to mature. The plots of Zr and (La/Yb)_N, Th/Sc and (Gd/Yb)_N ratios show the studied shales are positive correlated and fall away from the zircon addition domain, thus confirming that they are immature to mature first cycle sediments.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100084"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424561","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":"Glacial-interglacial and millennial-scale changes in terrigenous supply and ocean circulation in the western South Atlantic","authors":"Igor M. Venancio ,&nbsp;João M. Ballalai ,&nbsp;Douglas V.O. Lessa ,&nbsp;Thiago S. Figueiredo ,&nbsp;Raissa Tayt-Sohn ,&nbsp;Marianna C. Motta ,&nbsp;Aurélio F. Silva ,&nbsp;Nathalia O. de Lima ,&nbsp;Beatriz C.O.D.S.S. da Silva ,&nbsp;Rut Díaz ,&nbsp;Manuel Moreira ,&nbsp;Anderson G. de Almeida ,&nbsp;Ana Luiza S. Albuquerque","doi":"10.1016/j.eve.2025.100066","DOIUrl":"10.1016/j.eve.2025.100066","url":null,"abstract":"<div><div>Oceanic circulation changes play a fundamental role in shaping past climate variability in northeastern Brazil, influencing precipitation patterns and sediment transport on glacial-interglacial and millennial timescales. However, the extent to which these processes vary across different water depths and their geochemical imprints in marine sediments remain poorly constrained. Here, we present multiproxy geochemical records from three sediment cores in the Sergipe Basin, located off northeastern Brazil, spanning the last 45,000 years. Variations in Fe/Ca, Zr/Rb, TOC, CaCO₃, and sulfur content reveal distinct glacial-interglacial shifts, with enhanced terrigenous input and reduced carbonate deposition during glacials, likely linked to lower sea level and changes in ocean circulation. Millennial-scale fluctuations in sulfur and Zr/Rb suggest variations in deep-water ventilation and bottom-current speed. These results provide new insights into the regional paleoceanographic evolution of the western South Atlantic and reinforce mechanisms driving sedimentary responses to past climate variability.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100066"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808342","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":"Unravelling paleoenvironmental dynamics across the cretaceous-paleogene (K-Pg) boundary in the offshore Mannar Basin of the Northern Indian Ocean","authors":"S.S. Nawarathna ,&nbsp;P.L. Dharmapriya ,&nbsp;A.U. Wijenayake ,&nbsp;E.K.C.W. Kularathna","doi":"10.1016/j.eve.2025.100062","DOIUrl":"10.1016/j.eve.2025.100062","url":null,"abstract":"<div><div>Reconstructing the sedimentary environment and comprehension of the process of mineral enrichment rely significantly on lithofacies, which can be considered a proxy for the paleoenvironment. This study investigates the lithostratigraphic characteristics of the Late Cretaceous to Early Paleocene period, spanning the pivotal Cretaceous-Paleogene (K-Pg) boundary, in the Mannar Basin. Utilizing 25 drill cutting samples from the Dorado exploration well at intervals of 10 m, ranging from 2800 m to 3040 m in depth, various lithofacies were identified using Scanning Electron Microscope (SEM), polarizing microscope, and X-ray diffraction (XRD) analysis. Petrographic examinations revealed a diverse mineral arrangement, ranging from very fine to coarse-grained textures. Dominant minerals identified through XRD analysis include Quartz, Feldspar, Carbonate, and various clay minerals, facilitating shale classification. Five distinct lithofacies were delineated, encompassing calcareous, clayey, calcareous siliceous mixed, calcareous clayey mixed shales, and siliceous rocks. Noteworthy mineralogical compositions include abundant kaolinite, chlorite, and hematite minerals in the Maastrichtian succession, transitioning to montmorillonite, illite, and pyrite dominance in the Early Maastrichtian succession. Through clay mineralogy, this study discerns significant shifts in paleoenvironmental conditions, ranging from anoxic, arid to semi-arid climates during the Campanian to warm/wet, oxidizing environments during Maastrichtian, and finally to arid/semi-arid conditions during the early Paleocene. Additionally, evidence of early burial diagenesis and Late Maastrichtian sea-level regression is identified, contributing to a comprehensive understanding of environmental dynamics during this critical geological period in the Mannar Basin in the Equatorial Margin of the Northern Indian Ocean.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100062"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}