Atmospheric and Oceanic Sciences

ABSTRACT The metallogenic epochs evident in the Vindhyan Supergroup (VSG) are comparable to those of other Mesoproterozoic basins in the country. Recent advances in geological, geophysical, and geochemical fields have led to numerous discoveries over the past twenty years of exploration in the Vindhyan Basin (VB). The 200km-long Panna Diamond Belt (PDB) has revealed new Clans of Kimberlite Rocks (CKRs) within the Kaimur Group, as well as secondary diamond deposits found in the palaeo-placers and Quaternary sediments of the Rewa Group. In addition, uranium-bearing horizons associated with organic and carbonaceous matter in the Kaimur Group, arsenopyrite-associated gold in porcellanite, and placer gold at the base of the VSG have been identified. Rich glauconitic beds occur in the Semri and Rewa groups, whereas vanadium, titanium, and gallium are present in bauxite within the Kaimur and Rewa groups. New gas and oil-producing fields in the Semri and Kaimur groups present immense opportunities for the economic development of the area. However, the challenge lies in transforming these areas into productive centres. Geological models for exploration have been prepared and are expected to yield positive outcomes with new governmental support. The beneficiation of low-grade ore poses a significant challenge but offers substantial opportunities for the non-diamond mineral sector within VB. This paper discusses the known and recently discovered mineral occurrences and deposits, genetic aspects, current exploration status, challenges, and opportunities for mineral development in the VB.

Bird-aircraft collisions (bird strikes) pose threats to aviation safety and avian life. One of the tenets of airport-based management strategies to prevent bird strikes is the reduction of bird density within established separation distances from air operations areas. The rationale is that higher local bird densities could increase the spatial and temporal overlap in the use of airspace by both birds and aircraft, leading to a higher frequency of bird strikes. However, the strength and direction of this relationship have not been evaluated across published studies. This is an important gap, given how entrenched this assumed relationship has become to allocate limited resources to airport wildlife management. In this study, we assessed the strength of the relationship between avian abundance and bird strikes across studies using a meta-analytic approach. Through a reproducible literature search and screening criteria, we identified 20 outcomes (i.e., effect sizes) from 13 studies. We conducted a multilevel meta-analysis and found a positive correlation (Pearson's r = 0.520, 95% confidence intervals: 0.308-0.683), supporting the positive relationship between bird abundance and bird strike frequency. We additionally found evidence that the existing literature has high levels of between-study heterogeneity and publication bias, low statistical power, and multiple methodological concerns. These issues suggest that our effect size estimation should be interpreted with care. Given the limitations of the published literature testing this relationship, we provide a set of methodological recommendations for improving future experiments. We call for prioritizing the empirical testing of the abundance-bird strike relationship on and near airports across the world, and the standardization of bird survey approaches. These future tests are key to aligning management efforts to local airport needs.

Ground-motion parameters for different site conditions are conventionally prescribed in seismic design codes worldwide, based on post-earthquake damage surveys and statistical analyses of strong-motion databases. Design response spectra thus constitute the primary basis for engineering aseismic design, yet their shapes and characteristic parameters differ markedly among national codes. Systematic computations reveal that code-specified spectral shapes deviate appreciably from recorded earthquake spectra, providing an incomplete representation of site-specific ground-motion characteristics.To address this limitation, 1227 horizontal acceleration records were compiled and classified by magnitude, source distance and site class. Mean dynamic amplification spectra were computed for each subset, and numerical computation were performed to derive an improved analytical expression for the design spectrum. A genetic-algorithm-based calibration procedure was subsequently developed to determine optimal model parameters. The applicability of the proposed approach was examined by calibrating spectra for four independent strong-motion records; spectral parameters obtained with the improved shape were compared with those derived from the conventional code spectrum.Results demonstrate that the refined spectral form captures the frequency-dependent characteristics of earthquake response spectra more accurately than existing representations. The proposed calibration framework offers a valuable reference for advancing design-response-spectrum studies and for the potential updating of seismic design codes.

Background Indigenous hill communities on a forested plateau in southern India have shared their landscape with resort tourism for over 3 decades. Infrastructure has improved visibly. But whether tribal households are genuinely more secure—in ways that last—has never been examined at the community level. This study provides that evidence for the first time. Methods A concurrent mixed methods design combined a household survey across all settlements in Tamil Nadu with field observation and community conversations in Tamil. Social mobility and sustainable livelihood were measured through validated scale instruments and integrated at interpretation. Results A fundamental paradox emerged: households that have advanced educationally have done so at measurable cost to livelihood security. Social mobility and sustainable livelihood move in significantly opposite directions. Tourism employment, despite 3 decades of growth, confers no income advantage over other work. Land title is absent or disputed for the majority of households. Infrastructure gains reflect government welfare programmes more than tourism benefit, while tourism has contributed to land loss, groundwater depletion, and enclosure of natural commons. Conclusion Resolving this paradox requires implementing land rights protections, equitable benefit sharing from tourism, gender-inclusive education, and environmental safeguards—frameworks that exist in law but remain inadequately implemented on the ground.

Abstract In 2023, the Mars 2020 Perseverance rover explored the youngest preserved deposits on the Western fan of Jezero crater, Mars: a field of meter‐scale boulders dispersed above the previously explored sandstone and siltstone units. Reflectance spectra of the boulders delineated two classes, one olivine‐bearing and one pyroxene‐bearing. A representative boulder from each class was analyzed; here, we present proximity data from the olivine‐rich target, Falcon Lake, revealing a magnesian dunite (Fo 74 ). Such magnesian dunite is distinct from other igneous materials observed in Jezero and consistent with crystallization from a mantle‐derived partial melt. Micron and mm‐scale secondary minerals, identified on the abraded patch of Falcon Lake, include Mg‐serpentine, Fe‐Mg carbonate, and Mg,Fe sulfate. This alteration sequence records sequential precipitation from a single evolving fluid, and the coexistence of disequilibrium sulfate and siderite represents a microscale analog to planet‐wide associations and detections of carbonates and sulfates.

Abstract Some large igneous provinces (LIPs) are associated with precursory carbonatite eruptions. Models for precursory carbonatites invoking partial melting of a carbonate metasomatized lithosphere appear implausible, given the long time needed for heat conduction from the plume head. Instead, we consider that the plume, not the lithosphere, is the source of carbon. We explore a range of carbon concentrations in the plume source (196 C 440 ppm) and various melting depths of carbonate‐bearing peridotite, depending on the mantle redox state. Our numerical simulations provide a fluid dynamically consistent evolution of the plume‐lithosphere system and enable us to calculate the ascent velocity of carbonate melts. Moreover, we advect millions of passive tracers to follow the 3‐D trajectories of melts. The term “precursory‐C” indicates plume carbon that has reached sub‐lithospheric depths (140 km) before the onset of anhydrous silicate melting. For models with carbonatite melt produced at great depths (200 km), we find that the precursory‐C flux can be up to 6 × mol(C)/yr during a time period of ∼2 Myr preceding the onset of anhydrous silicate melting. The considerable mass of precursory‐C, up to 2 × kg(C), can explain carbonatite complexes predating main phase volcanism in the Paraná province and the Deccan Traps. For some LIPs, environmental and biotic perturbations, indicated by negative carbon isotope excursions and mass extinctions, predate the main phase LIPs eruptions. For the Central Atlantic Magmatic Province (CAMP) we suggest that precursory‐C could represent a non‐negligible carbon source for the earliest volcanism, likely synchronous with the end‐Triassic extinction.

Heterogeneities of Late Cretaceous tropical carbonate platforms of the Middle East are yet to be fully understood. The analysis of carbonate microfacies with materials obtained from exploration wells can contribute to filling the noted gap. The present study focuses on the Coniacian–Santonian deposits near the Kazerun fault in the central part of the southern Zagros. The material from two exploration wells drilled east of this fault was used to establish carbonate microfacies and shale lithofacies and propose a depositional model. Six carbonate microfacies signify the existence of a homoclinal ramp, and inner-ramp environments were especially common. The stratigraphical distribution of the established microfacies made it possible to document a long-term transgression–regression cycle, which looks dissimilar to the global sea-level changes. Another control of this cycle might have been tectonic activity, particularly the activity of the Kazerun fault. The comparison of the lines of evidence from two wells east of this fault and two other wells west of this fault indicates striking differences.

Introduction Bamboo plantations are highly valued for their biomass production and soil enrichment potential under diverse ecological conditions. However, information on performance of Phyllostachys pubescens under different tree canopies in the warm-temperate Himalayas remains limited. Methods Therefore, the present study evaluated the growth performance, biomass production, litter dynamics, and soil physicochemical and biological activity of an 8-year-old P. pubescens plantation established under the canopy of tree species viz. Alnus nitida, Platanus orientalis, Populus deltoides , and Robinia pseudoacacia in warm temperate regions of north-western Himalayas. Field sampling was carried out during 2016–2017 utilizing a randomized block design with factorial arrangements to assess the growth parameters, biomass accumulation, litter dynamics, soil physico-chemical properties, and microbial activity. Results Results revealed that the integration of P. pubescens with P. orientalis significantly enhanced growth attributes, namely, culm diameter, culm height, and culm density. Biomass accumulation was also maximum under this combination, with total biomass reaching 6.47 Mg ha -1 , comprising both aboveground (4.96 Mg ha -1 ), and belowground (1.51 Mg ha -1 ) components. Leaf litter accumulation was also notably higher in the P. orientalis -bamboo-based system, indicating improved nutrient return. Further, soil analysis showed enhanced organic carbon (15.18 g kg -1 ), available nitrogen (355.76 kg ha -1 ), phosphorus (57.42 kg ha -1 ), and potassium (313.66 kg ha -1 ) under the same combination relative to other tree-bamboo combinations. Soil biological activity, including microbial biomass carbon and microbial populations, was also significantly higher under P. pubescens + P. orientalis plantation, particularly in surface soils. Overall, P. pubescens demonstrated superior biomass production and nutrient cycling efficiency when grown under P. orientalis , followed by A. nitida, R. pseudoacacia , and P. deltoides . Discussion These results indicate that bamboo-tree mixed plantations have the potential to enhance ecosystem productivity, nutrient cycling, and soil health, thus offering a sustainable land use option that could be implemented in similar warm-temperate mountain areas facing soil degradation and climate-related stresses.

Introduction Genetic diversity and population structure are critical for understanding species distribution, environmental adaptability, and responses to anthropogenic disturbances. Dendrocalamus longispathus , a commercially and ecologically important bamboo species in North East India, remains understudied in terms of its population genetics. This study aims to assess the genetic diversity and structure of this species across its natural range in Mizoram and Tripura. Methods Leaf samples were collected from 12 populations and analyzed using 13 polymorphic simple sequence repeat (SSR) markers. Genetic diversity parameters, including number of alleles, allelic richness, heterozygosity, and inbreeding coefficients, were estimated. Population structure was examined using Bayesian analysis, Neighbor-Joining method based genetic clustering, and principal coordinate analysis (PCoA). Results The analysis revealed moderate genetic diversity, with mean number of alleles (Na = 2.84), effective alleles (Ne = 1.87), and expected heterozygosity (He = 0.362). Observed heterozygosity (Ho = 0.234) was lower than expected, indicating inbreeding, supported by a positive inbreeding coefficient (F IS = 0.306). Populations from Mizoram exhibited higher allelic richness compared to those from Tripura. AMOVA showed that 70% of genetic variation occurred within populations and 30% among populations (F ST = 0.297), indicating very high levels of genetic differentiation with low gene flow (Nm = 0.86). Bayesian analysis identified three genetic clusters (K = 3), with most populations clearly structured except one admixed population. Overall, pattern of genetic clustering between population was largely aligned with geographic proximity. Discussion The findings indicate moderate genetic diversity, very high genetic differentiation, and robust genetic structure in D. longispathus populations, with evidence of limited gene flow and inbreeding. These results highlight the need for targeted conservation strategies and the use of genetically diverse populations for plantation and sustainable management programs.

Media representations and narratives around climate change are often dominated by certain voices whilst others are excluded or marginalized. This study investigates media portrayal of climate change around Glasgow's COP26, focusing on the prominence or exclusion of certain voices. Analyzing US and UK newspaper coverage, it identifies variances in representation, with Indigenous and minority voices marginalized in favor of political, scientific, and activist perspectives from the Global North. Through content analysis, the research explores how power, access, and frames shape media narratives on climate change, underscoring the need for more inclusive discussions.

ABSTRACT The Dharwar Craton in southern India represents one of the most ancient and extensively studied segments of the Indian shield, characterised by a complex and prolonged geological evolution spanning from the early Archaean to the Proterozoic. It comprises a wide array of granitoids and gneisses, reflecting multiple episodes of magmatism, crustal reworking, and tectonic deformation. Based on geochronological and metamorphic evidence, the craton is subdivided into the Palaeo- to Mesoarchaean Western Dharwar Craton (WDC) and the predominantly Neoarchaean Eastern Dharwar Craton (EDC), separated by a major shear zone along the Chitradurga greenstone belt. The EDC features narrow, linear schist belts (e.g., Kolar, Raichur, Hutti, and Ramagiri) characterised by gold mineralisation and widespread granitoid intrusions. In this paper, granitoid plutons adjoining the Raichur belt are studied from their petrographic and geochemical aspects. These granitoids include tonalite-granodiorite, sanukitoid, biotite granite, two-mica granite, and hybrid varieties. SiO2 in these granitoids ranges from 58 to 74 wt%, and A/CNK 0.68 to 1.31. Further, they are characterised by a fractionated Rare Earth Element (REE) pattern (LaN/YbN=12-91) and a distinct negative Eu anomaly. Their geochemical characteristics suggest complex petrogenetic processes involving partial melting of mantle and crustal sources, magma mixing, and crustal reworking. Their spatial distribution and geochemical signatures indicate a dynamic tectonic environment involving terrane accretion, crustal thickening, and thermal perturbations during the late Archaean to early Proterozoic transition.

ABSTRACT In this contribution, we address how plate tectonics can be recognised from the geological record. We explore evidence for when the continental crust became rigid enough to facilitate plate tectonics, through the onset of dyke swarms and large sedimentary basins. Metamorphic regimes are sensitive to tectonic setting, but blueschists are largely restricted to terrains < 700 Ma old. Older terrains tend to be characterised by medium T/P (Barrovian) and high T/P (Buchan) metamorphism, which tend to be linked to crustal thickening and extension. Granulite facies metamorphism provides evidence for crustal thickening regionally by the late Archaean. Minor and trace element ratios of magmatic rocks are widely used to distinguish magmas generated in subduction and non-subduction-related settings. Both features are observed in mafic rocks from 3.8-2.7 Ga, and encouragingly, there appear to be links between geochemistry and tectonic style, in those rocks with non-subduction features, they tend to be associated with dome and basin architecture. Granite-greenstone terrains are characterised by bimodal magmatism, and while this is a feature of intraplate magmatism in younger terrains, it remains unclear how readily bimodal magmatism may be generated by subduction-related processes in the Archaean. Archaean cratons evolve through a period of mafic/ultramafic-TTG magmatism to more granitic phases with sanukitoid magmas as the cratons stabilise and sedimentary basins develop, and different cratons stabilised at different times from 3.1–2.5 Ga. Globally, there is a marked change in the estimated composition of juvenile continental crust from mafic to more intermediate compositions at ca. 3 Ga. It is argued that crustal evolution may be better constrained through crustal archives, rather than the development of depleted mantle, and by an apparent reduction in the rate of crustal growth at ca. 3 Ga. This is attributed to an increase in the rates at which continental crust was destroyed, and that, coupled with the other changes at the end of the Archaean, is taken to reflect the onset of plate tectonics as the dominant global regime.

Abstract The Cretaceous/Paleogene (K/Pg) Chicxulub impact produced globally synchronous enrichments of highly siderophile elements (HSEs) and a pronounced decline in marine osmium isotope ratios ( 187 Os/ 188 Os), forming a key geochemical marker of the boundary. However, precise identification of the K/Pg boundary remains challenging in extensive pelagic regions dominated by deep‐sea red clay, where calcareous and/or siliceous microfossils are poorly preserved. Here we identify the K/Pg boundary in a pelagic clay sequence from piston core KR13‐02 PC05 recovered near Minamitorishima Island in the western Pacific Ocean using HSE concentrations and Os isotope stratigraphy, supported by ichthyolith biostratigraphy and magnetostratigraphy. A distinct Ir enrichment (up to ∼16 ppb) coincides with the most unradiogenic 187 Os/ 188 Os value (∼0.14) at ∼9.95 mbsf, defining a geochemical horizon consistent with the global signature of the Chicxulub impact. Polarity chrons spanning C29n–C30n and ichthyolith assemblages support the placement of the K/Pg boundary and provide a robust chronological framework. Above the boundary, 187 Os/ 188 Os ratios remain persistently unradiogenic over a stratigraphic interval corresponding to several hundred thousand years. This prolonged signal reflects the integrated effects of extremely low sedimentation rates, sediment reworking by bioturbation, and background extraterrestrial dust inputs. These results demonstrate that sedimentary Os isotope records in low‐accumulation pelagic clay do not necessarily represent a simple archive of contemporaneous seawater composition. Instead, depositional and diagenetic processes can substantially modify post‐impact isotopic signals. Our findings highlight the necessity of multi‐proxy chronological control and careful geochemical screening when reconstructing oceanic responses to the K/Pg impact on microfossil‐poor pelagic environments.

In bamboo-based restoration systems, matching harvested culms to appropriate end uses is complicated by strong culm-to-culm variability and by grading practices that remain uneven or context-specific. This study examined whether measured culm descriptors could predict bending strength (BS), modulus of elasticity (MOE), and embodied carbon (EC) as a basis for culm-level assessment particularly for structural applications and lower-carbon allocation decisions. Using 102 culm specimens of Bambusa blumeana and Bambusa vulgaris tested under ISO 22157-type bending procedures, culm descriptors were related to BS, MOE, and EC through an interpretable, data-driven screening framework. Predictive performance was high across all three indicators (R² = 0.96–0.98), enabling model-based translation of culm-level heterogeneity. Key results show that favorable structural and carbon outcomes do not arise from a single universal trait but instead reflect different trait combinations and trade-offs across indicators. Within the study’s dataset, culms approximately 80–90 mm in diameter and 1.6–2.1 kg/m in linear mass tended to combine stronger predicted structural performance with lower embodied carbon. While denser culms (about 725 kg/m³) with relatively thin walls (<8 mm) were associated with favorable stiffness in specific prediction regimes. By translating trait-level variability into candidate allocation cues, the framework provides a transparent basis for assessing heterogeneous bamboo stocks and guiding decisions that direct culms toward structural and lower-carbon uses, thereby supporting restoration objectives in managed bamboo systems.

Citizen science plays an increasingly important role in generating scientific knowledge and supporting environmental and social action. However, its potential to address complex global challenges remains underutilised. This study explores how citizen science can be improved by involving the public in all stages of scientific research. Using participatory research methods, online surveys and group discussions were conducted with researchers, citizen scientists, and Indigenous participants. Thematic coding was used to identify key challenges, opportunities, and best practices to enhance citizen science initiatives. Additionally, nine case studies were reported using the Standardised Data on Initiatives (STARDIT) reporting tool. The study identified key strategies for improving involvement, engagement and retention in citizen science initiatives. Findings underscore the importance of inclusive, evidence-informed approaches such as targeted outreach, fair compensation, tailored support, and co-creation practices. Ensuring data quality and fostering trust require adherence to FAIR data principles (findable, accessible, interoperable and reusable), transparent validation and sharing processes, and establishing ethical research partnerships. Persistent challenges include short-term funding, which undermines long-term project sustainability, and the lack of centralised support for ethics and project management. Formal recognition of citizen scientists through co-authorship, standardised training, and professional development opportunities can further strengthen involvement and build capacity. Finally, emerging technologies, including artificial intelligence and open data platforms, present opportunities to scale and improve efficiency, provided they are implemented with appropriate ethical safeguards and investment. Drawing together these insights, we provide 10 actionable recommendations for citizen science in the 21st century. These highlight the importance of embedding citizen science in national research infrastructure, education, and policy, alongside consistent evaluation and reporting, to improve its inclusivity, longevity, and impact. We conclude by arguing that as the world confronts climate change, public health crises, and biodiversity loss, broader public involvement in science is key for equitable, efficient and evidence-informed responses.