Evolving Earth最新文献

{"title":"Variscan Gornjane granitoid as an alternative cold-water reservoir in the ore-baring and mining area of eastern Serbia: Quantitative-qualitative characterization (Carpathian-Balkan belt, Getic unit)","authors":"Goran Marinković ,&nbsp;Marina Magazinović ,&nbsp;Darko Spahić ,&nbsp;Nataša Obradović ,&nbsp;Maja Poznanović Spahić ,&nbsp;Ivana Jovanić ,&nbsp;Bogdan Kuzmanović","doi":"10.1016/j.eve.2024.100045","DOIUrl":"10.1016/j.eve.2024.100045","url":null,"abstract":"<div><div>The diminishing high-quality groundwater reservoirs have sparked significant interest in hard-rock aquifers, especially in active mining and raw material exploration areas. This paper aims to forecast the quantity and quality of alternative water resources in the area, thus facilitating the planning and design of the existing water resource systems. The focal point is the groundwater accommodated within basement-type alternative igneous aquifers nestled within an active mining and exploration province belonging to the Carpathian-Balkan fold-and-thrust belt (Banat-Timok Province/Banatitic Belt, sector in eastern Serbia). Despite their lower water-bearing capacity, we underscore the significant hydrogeological potential of natural water igneous-type aquifers, such as the Variscan Gornjane massif.</div><div>For the first time, this research identifies different reservoirs across the granite massif, providing a fresh perspective on the regional water resource systems. By categorizing reservoirs based on porosity type, flow rates, depth of reservoir rocks (in the depth range of 50 m), and distribution, this study significantly enhances the forecasting of the new water resource system, underlining the importance of this research in the field of water resources and mining. In addition to faulted sections of granite, aquifers are formed in the area characterized by weathered and decomposed granite fragments, often referred to as gruss deposits. The gruss layer has a flow rate reaching up to 0.01 l/s. In terms of the water quality, the groundwaters of the Gornjane granite massif mostly do not contain elements that are above the maximum permitted concentrations for drinking water. However, the occurrence of the elements Fe Mn in some water samples and the presence of Al Pb in one sample, as well as Se, As, Cu, Zn, Ag, Cd, Ga, and Bi, suggest the contact of water with sulfide mineralization detected in granite rocks of Rudna Glava-Tanda-Luka area, raising concerns about potential water quality issues.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100045"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097470","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":"Analysis and prediction of sea level rise along the U.S. East and Gulf coasts and its socio-economic impacts on the nearby inland areas","authors":"Sharmin Majumder ,&nbsp;ANM Nafiz Abeer ,&nbsp;Musfira Rahman ,&nbsp;Md Abul Ehsan Bhuiyan","doi":"10.1016/j.eve.2024.100051","DOIUrl":"10.1016/j.eve.2024.100051","url":null,"abstract":"<div><div>Floods are among the most frequent and devastating natural disasters, causing severe global economic damage, yet timely and accurate warnings of flash flood impacts on ungauged locations remain challenging. Sea level rise (SLR) is a substantial factor that contributes to flooding, particularly along the coastal regions of the United States. This study presents a comprehensive analysis of historical tide gauge records from 1900 to 2021 to investigate spatio-temporal dynamics of mean sea level (MSL) along the U.S. East and Gulf coasts and develops a forecasting model to predict future MSL using these dynamics. We employed empirical orthogonal functions (EOF) analysis and dynamic mode decomposition (DMD) with time delay embedding to analyze and forecast MSL data. SLR dynamics and trend vary across different parts the U.S. coasts. Our proposed approach aids in identifying the regions most susceptible to SLR. To assess the socio-economic impact on the coastal regions due to SLR, we propose a framework that integrates the mean sea level data from tide-gauge stations with socio-economic variables of neighboring counties through interaction structure learning techniques. Furthermore, we empirically demonstrate the implications of our proposed framework in highlighting socio-economic factors affected by SLR. In conclusion, our predictive method elucidates the spatio-temporal dynamics of mean sea level, while our interaction learning framework reveals SLR’s impact on coastal socio-economic attributes.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100051"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097471","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":"Integrated geochronological and chemostratigraphic study of middle Miocene strata (Ogallala Group) at the eastern margin of the North American Great Plains","authors":"Jon J. Smith ,&nbsp;R.M. Joeckel ,&nbsp;Holly L. Field ,&nbsp;Greg A. Ludvigson ,&nbsp;Andreas Möller ,&nbsp;Anthony L. Layzell ,&nbsp;Shane T. Tucker","doi":"10.1016/j.eve.2024.100050","DOIUrl":"10.1016/j.eve.2024.100050","url":null,"abstract":"<div><div>Global and regional shifts in climate and environmental conditions during the Miocene gradually gave rise to the grassland biomes that now dominate the modern North American Great Plains. Strata comprising the Ogallala Group provide critical information for understanding these transitions. Geologic mapping and scientific drilling at the eastern edge of the Ogallala Group in northeastern Nebraska, reveal a basal, pedogenically modified siltstone-dominated interval that was hitherto barely known and never firmly placed in a regional stratigraphic context. Herein, we distinguish this basal siltstone unit of the Ogallala Group in the eastern Niobrara River Valley from the overlying sand-dominated strata of the Valentine Formation on the basis of lithologic characteristics, trends in organic-carbon δ¹³C chemostratigraphic profiles, and U-Pb dating of detrital zircons. This siltstone unit bears some similarities to the middle Miocene Fort Randall Formation in its type area, which lies ∼75 km to the northwest in the Bijou Hills of South Dakota. Organic δ¹³C chemostratigraphic profiles generated from outcrops and cores of the basal siltstone in Nebraska indicate that the study area consistently had C₃-dominated paleofloras while it was deposited, presumably in the middle Miocene. The youngest detrital zircons from the siltstone-dominated unit were probably deposited directly onto ancient landscapes by supervolcanic airfall events originating some 1500 km to the west near the intersection of the boundaries of present Oregon, Nevada, and Idaho. These youngest zircons yield a maximum depositional age of ∼15 Ma. This age is in general agreement with the Barstovian (Ba2) mammal biostratigraphic age of the Fort Randall Formation in South Dakota. It is also significantly older than the ∼13 Ma youngest single grain zircon we recovered from sands of the overlying Valentine Formation. Thus, we propose that our integrated geochronologic and chemostratigraphic approach can date Late Cenozoic strata with constraints on the order of 1 m.y., portending broad applicability of our methods in reducing the uncertainties in dating terrigenous sediments in continental basins.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100050"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097469","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":"Genesis, classification, tectonic setting and economic potential of global granitic pegmatites: A review","authors":"P.L. Dharmapriya ,&nbsp;D.W.M. Disanayaka ,&nbsp;H.M.T.G.A. Pitawala ,&nbsp;Sanjeewa P.K. Malaviarachchi ,&nbsp;N.D. Subasinghe","doi":"10.1016/j.eve.2025.100059","DOIUrl":"10.1016/j.eve.2025.100059","url":null,"abstract":"<div><div>Granitic pegmatites have attracted a significant interest of petrologists and mineralogists due to their complex genetic characteristics and substantial economic value. Although numerous reviews addressed specific aspects such as genesis, classification, economic potential, and tectonic setting, a comprehensive review integrating all these facets in a single article has been lacking. This study fills that gap by offering a holistic review that synthesizes these key dimensions. It examines prevailing theories on pegmatite genesis, traces the evolution of classification systems, and assesses the economic importance of pegmatites as sources of industrial minerals, strategic metals, and gemstones, as well as their association with different tectonic settings.</div><div>The crystallization of the majority of granitic pegmatites is widely acknowledged to occur in the presence of a viscous, volatile-rich polymerized silicate magma, concomitant with supercritical aqueous fluids. Consequently, granitic pegmatites can frequently be conceded as a hybrid rock derived through igneous and hydrothermal processes. Various criteria, such as the emplacement depth of granitic pegmatites, their association with metamorphism and granitic plutons, geochemical signatures, and their relationships with host rocks, have traditionally been employed for the classification of granitic pegmatites. However, none of the classifications has been accepted unequivocally.</div><div>Pegmatitic melt is often rich in chemical constituents (including volatiles) that are incompatible in common rock-forming minerals. In addition to rare earth elements, pegmatites are commonly enriched in rare elements such as Li, B, Be, Cs, and Ta. Because they are incompatible in common rock-forming minerals, these elements tend to create specific mineral phases that can host themselves. As a result, the concentration of trace elements such as Li, B, Cs, Ta, and Bi in these bodies are enriched to levels as high as a thousand times higher than the typical crustal abundance.</div><div>Granitic pegmatites encompass a diverse array of economic commodities, serving as repositories for industrial minerals and sources for strategic metals like Ta, Cs, Sn, Nb, Be, Sb, W, Co, and rare earth elements. Furthermore, they contribute as reservoirs of fluxing components, including Li, P, F, and B, while serving as sources of precious and semi-precious gemstones and some radioactive minerals. The global distribution of pegmatite ages suggests a linkage between the age of pegmatite formation and supercontinent assembly. The Li, Ce and Ta enriched (LCT) granitic pegmatites form part of the orogenic suites associated with crustal shortening in zones of subduction and instances of continental collision. The Nb, Y, and F-enriched (NYF) pegmatites are mainly interpreted as products of anorogenic suites and formed mainly in extensional settings.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100059"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521208","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":"Relief inversion and denudation dynamics in a semi-arid landscape (Araripe Plateau, NE Brazil): Insights from cosmogenic nuclides and geomorphic surfaces","authors":"José Guilherme de Oliveira ,&nbsp;Lionel L. Siame ,&nbsp;Leonardo José Cordeiro Santos ,&nbsp;Lëatitia Leanni ,&nbsp;Simone Cardoso Ribeiro ,&nbsp;Frederico de Holanda Bastos ,&nbsp;ASTER Team","doi":"10.1016/j.eve.2025.100064","DOIUrl":"10.1016/j.eve.2025.100064","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Araripe Plateau, a relict landscape in the semi-arid northeastern region of Brazil, provides a unique setting to investigate sediment dynamics and long-term denudation rates using &lt;em&gt;in situ&lt;/em&gt; cosmogenic nuclides ( &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; and &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; ). In this study, we analyze bedrock and modern river sediment samples to determine denudation rates, evaluate sediment mixing, and assess the landscape’s response to erosional processes. Our results indicate that, while bedrock samples largely reflect a state of cosmogenic secular equilibrium, river-borne sediments exhibit significantly lower &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; (Al-Be) ratios, pointing to a mixing process between freshly eroded material and recycled sediment from buried sources in the alluvial plain. Denudation rates in the Araripe region are low (&lt;span&gt;&lt;math&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; 20 m Myr&lt;sup&gt;−1&lt;/sup&gt;) and show limited variability across different slopes and precipitation levels, consistent with other slow-tectonic settings like the Anti-Atlas in Morocco. However, differential denudation between the sedimentary rocks of the Araripe Basin and the crystalline basement rocks primarily controls relief evolution, driving the process of topographic inversion along the Ceará and Pernambuco slopes. In the Parnaíba basins, while this pattern holds, watersheds developed in Palaeozoic sedimentary rocks exhibit notably higher erosion rates, indicating faster landscape evolution in these areas. A speculative analysis of the geomorphic surfaces around the Araripe Plateau suggests long-term denudation rates of 3–6 m Myr&lt;sup&gt;−1&lt;/sup&gt;, consistent with our cosmogenic nuclide-derived rates. These findings indicate a stable landscape with low relief, where tectonic activity has minimal influence, and lithological factors play a dominant role in controlling erosional patterns. The differential denudation rates across the plateau, supported by geomorphic metrics and the spatial distribution of laterite covers, provide insights into the ongoing evolution of this relict landscape and potential future drainage rearrangements. Our study underscores the complexity of sedimentary processes and the importance of combining cosmogenic nuclide analysis with geomorphic context to understand the interplay between erosion, sediment mixing, and landscape stability. Using a two-source mixing model, we estimate that up to 84% of river sediment in some watersheds originates from previously buried material. This trend correlates with the extent of the cumulative drainage network, suggesting that longer transport pathways enhance sediment mixing. The apparent burial times inferred from Al-Be ratios also show a negative correlation with the fraction of freshly eroded material, highlighting the role of deep-seated sediment contributions in building the cosmogenic signal. This integrated approach provides a refined perspective on sediment dynamics and denudation in slowly eroding landscapes, with broade","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100064"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610694","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":"Response of tropical rainforest to warming during Middle Eocene Climate Optimum (MECO): Evidence from palynological record from the Bartonian deposits of Kutch Basin, Western India","authors":"Nazim Deori ,&nbsp;Poonam Verma ,&nbsp;Shailesh Agrawal ,&nbsp;M.G. Thakkar ,&nbsp;J.M. Patel","doi":"10.1016/j.eve.2025.100065","DOIUrl":"10.1016/j.eve.2025.100065","url":null,"abstract":"<div><div>The Middle Eocene Climatic Optimum (MECO), at ∼40 Ma, is considered a transient global hyperthermal event that superimposed the long-term cooling phase of the middle to late Eocene. The event is largely construed from the marine province but less in the continental depositional systems. The present palynological and isotopic study from the age-constrained Harudi Formation succession of the Kutch Basin, Western India, aims to understand the impact of MECO warming on Eocene tropical rainforest and environments. The carbon isotopic characterization (δ¹³C values) of the studied succession exhibited a pronounced negative Carbon Isotope Excursion (CIE) of about 2.5 ‰, correlated to the peak warming phase of the MECO event. The middle Eocene climate was warm and wet, as indicated by the existence of a diverse array of tropical flora in the region. Notably, the peak warming MECO phase is characterized by the infringement of deciduous elements, indicating the seasonality in rainfall pattern. The subdued mangrove community is also a testimony to salinity fluctuations in the depositional system due to intermittent surges of fresh-water flux. During the recovery phase after the peak warming, the evergreen flora restored in tropical rainforests and mangroves flourished under relatively stable environmental conditions. However, the diversity patterns show an overall decline in diversity. On a wider perspective, the study demonstrates the sensitivity of the tropical rainforests and mangrove communities in response to fluctuating environmental conditions during the high atmospheric CO₂ levels and increased temperatures of MECO.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100065"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851846","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":"Ocean acidification signals through deep time: A review of proxies","authors":"Subham Patra,&nbsp;Jahnavi Punekar","doi":"10.1016/j.eve.2024.100056","DOIUrl":"10.1016/j.eve.2024.100056","url":null,"abstract":"<div><div>Anthropogenic CO₂ levels have increased by nearly 40% from preindustrial levels, with about 30% absorbed by the ocean leading to ocean acidification (OA). The associated carbonate undersaturation can critically affect marine calcifying communities. Major disruptions in the marine carbonate cycling are common throughout the Phanerozoic stratigraphic record, and often coincide with major mass extinctions and faunal turnover events. The anthropogenic OA is progressing at a rate nearly ten times faster than similar events of the past 300 million years. This makes OA research of high priority, and entails a rigorous evaluation of OA events from deep time for perspective. Such efforts are contingent upon reliable proxies. This review compiles geochemical and foraminifera-based proxies, offering a critical assessment of their fidelity, ease of use, and application scope.</div><div>This study evaluates the scope and utility of documented observational and analytical proxies based on factors like the nature of data, and the time, effort and advanced analytical facilities involved. Foraminifera-based observational proxies like morphological and community responses to OA are effective but demand taxonomic expertise. They are further complicated by vital effects, metabolic trade-offs, the influence of stressors other than ocean acidification, and paleogeographic variability in both the magnitude of stress and the organisms' response to it. Well-calibrated analytical (geochemical) proxies offer the potential for rapid, high-resolution records across various sites. All proxies face challenges from diagenetic alterations, which can affect their reliability. However, this review offers the pros/cons and practical recommendations for proxy utility, emphasing the need for a multi-proxy approach to enhance accuracy and cross-verification. Future research must urgently address plankton community responses, OA-tolerant taxa, and localized calcification environments to grasp the full impact of acidification. It is critical to refine lesser-known proxies (e.g., S/Ca) and to rapidly expand datasets on carbonate system parameters across Phanerozoic OA events to advance our understanding and mitigation strategies.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100056"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140566","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":"Chemical weathering proxies: An assessment of their robustness to reconstruct Paleozoic climate conditions","authors":"Franciele Agnesa Trentin ,&nbsp;Joice Cagliari ,&nbsp;Karlos G.D. Kochhann ,&nbsp;Tracy Frank","doi":"10.1016/j.eve.2024.100054","DOIUrl":"10.1016/j.eve.2024.100054","url":null,"abstract":"<div><div>Several chemical weathering proxies for siliciclastic sedimentary deposits have been proposed over the last fifty years. However, only a few studies have evaluated their robustness for paleoclimate interpretation. Here, we compile published geochemical data for the Early Cambrian to Late Permian to statistically assess the robustness of weathering intensity proxies, as well as to account for biases that may affect the paleoclimatic interpretations. A principal components analysis (PCA) was conducted to assess the reliability of 15 chemical weathering proxies, considering paleoclimate categories inferred for each sedimentary succession. We test the consistency of our PCA model with independent datasets of Permian sedimentary rocks and modern soils. The distribution of paleoclimate categories follows a trend on the PC-1 axis, from arid conditions on the positive side to humid climates on the negative side. Modern soil samples show a similar distribution on the PC-1 axis, corroborating the interpretation that the first dimension of PCA in paleorecords is linked to chemical weathering intensity. Therefore, we suggest that all proxies represented by the PC-1 axis are suitable for chemical weathering intensity reconstructions, and, consequently, paleoclimate interpretations. However, it is necessary to consider other controlling factors that can affect the chemical weathering signal in deep-time siliciclastic sedimentary deposits, such as provenance, hydraulic sorting, diageneses, and recycling.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"3 ","pages":"Article 100054"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140578","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":"Mineralogical and geochemical studies of shales from Kopili Formation, Dima Hasao district Assam, North East India: Insights into diagenesis, deposition and provenance","authors":"Amit Tiwari ,&nbsp;S.L. Memory ,&nbsp;Joe Joseph ,&nbsp;R.R. Meshram","doi":"10.1016/j.eve.2024.100039","DOIUrl":"10.1016/j.eve.2024.100039","url":null,"abstract":"<div><div>The Eocene Kopili Formation in the Assam foreland basin records sediment sources, tectonic activity and depositional environments following the India-Eurasia collision. Mineralogical and geochemical analysis of these shales exposed near Garampani, Assam, NE India was conducted to study the diagenesis, palaeoweathering, palaeosalinity, redox conditions, tectonic settings and provenance. The Kopili Formation is composed of mainly shale with thin beds of limestone, black shale and sandstone and these units overlie the Upper Sylhet Limestone. The presence of goethite-rich phosphatic nodules, secondary precipitation within the fissile planes of shale and the occurrence of anatase, talc, smectite and chlorite suggest diagenesis. The prevalence of kaolinite and mean Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Al₂O₃/MgO and Rb/Sr values of 86.73, 97.26, 16.36 and 1.32, respectively indicates extensive source rock weathering in humid tropical climate. The Index of Compositional Variation (ICV) values ranging between 0.47 and 2.38 also signify high weathering and tectonically active basin. The Sr/Ba ratio 0.34 ± 0.27 (mean±2σ) suggest overall freshwater basin. The Ni/Co (2.84 ± 2.29), V/Cr (1.65 ± 0.45) and Ce/Ce∗ (0.97 ± 0.63) suggest fluctuating redox environment. The samples predominantly cluster in continental island arc domain on the Th-Sc-Zr/10, La-Th-Sc and Th-Co-Zr/10 discriminant diagrams. Elemental ratios of Th/Sc, La/Sc, Cr/Th with average 0.91, 3.18, 10.13 respectively and La/Th-Hf plot suggest a felsic source rock. The Kopili shale was deposited in freshwater, continental island arc basin with fluctuating redox conditions, receiving sediments from weathered Himalayan granites and gneisses under a warm and humid climate. Subsequently, they underwent diagenetic alteration by low-pH fluid(s).</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100039"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532619","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":"Morphometry and active tectonics of the Konkan coast, western India","authors":"Shatavisa Chatterjee ,&nbsp;Kutubuddin Ansari ,&nbsp;Mery Biswas ,&nbsp;Soumyajit Mukherjee ,&nbsp;B. Kavitha","doi":"10.1016/j.eve.2024.100041","DOIUrl":"10.1016/j.eve.2024.100041","url":null,"abstract":"<div><div>The Indian western coast is petroliferous and draws attention from academicians and industrial experts. In this work, geomorphic indices have been calculated to decode neotectonics of the Konkan onshore region on India's west coast. Earthquake and Bouguer anomaly data have been used along with the present-day stress data from the World Stress Map project. Gravity modeling was performed in order to gain seismotectonic insights. The b-values were determined using Z-MAP 7.1 (2021). Morphometric analysis at both linear and spatial scales were performed using the digital elevation model from the data derived from the Shuttle Radar Topography Mission, analyzed with ArcGIS 10.3 (2014) software. Maps depicting slopes, aspects, and reliefs were created. NW-SE trending lineaments in the Konkan plain guided the major stream courses. Two of the five watersheds, watersheds 4 and 5, reveal high tectonic activity, are landslide-prone and host hot springs. Interestingly, watersheds 4 and 5 show high b-values (except near the rivers' sources), low Bouguer anomalies, and higher Hypsometric integral values (0.18523 and 0.16698) than the other watersheds. A low b-value in watershed 3 indicates stress accumulation. Over a larger area, the gravity trend varies from ∼ −80 to 30 mGal. The lineaments diagram deduced from the first vertical derivative technique shows that the structural fabrics mostly trend ∼ NW-SE at the west of the Western Ghat Escarpment (WGE) while it is NE-SW at the east. The tilt derivative ratio technique reveals a major NE-SW trend to the west of the WGE and an E-W trend to the east. Structural interpretations based on drill-cores around Koyna combined with geophysical studies for deep crust will be required are required for a better understanding of the blind (active) structures in the region.</div></div>","PeriodicalId":100516,"journal":{"name":"Evolving Earth","volume":"2 ","pages":"Article 100041"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662892","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}