Search Results (90)

Lunar dark mantle deposits (DMDs), formed by explosive volcanic activity on the Moon, are typically composed of glass- and iron-rich pyroclastic materials, with slight variations in color, crystallinity, and TiO₂ concentration by region. This paper proposes a method for identifying DMDs using the YOLOv8 deep learning model, enhanced by the introduction of a multi-scale feature extraction (MSFE) module with an attention mechanism, which improves the model’s ability to detect targets at different scales. First, a DMD dataset was constructed using Lunar Reconnaissance Orbiter (LRO) data, with manual annotations of DMD regions and lunar image slicing to optimize computational efficiency. The YOLOv8 architecture, with the incorporated MSFE module, was then used to improve model accuracy in complex terrain. The experimental results showed that the improved DM-YOLO model achieved a precision (P) of 83.9%, a recall (R) of 83.2%, and a mean average precision (mAP@0.5) of 84.2%, representing increases of 15.2%, 14.4%, and 14.0%, respectively, over those obtained with the original YOLOv8 model. The predicted results were preliminarily verified using FeO abundance data and further confirmed by analysis of M³ spectral absorption features, showing strong consistency with known DMDs in terms of both chemical composition and mineralogical characteristics. Observations showed that DMDs were located primarily in the low- and mid-latitude regions of the Moon, with most deposits found in the lunar highlands. The findings suggest that the DM-YOLO model has significant potential for providing technical support for lunar exploration and resource development, particularly for identifying small-scale features that are difficult to annotate. Full article

This study examines magnesium potassium phosphate cements (MKPCs) modified with industrial wastes for extrusion-based 3D concrete printing, evaluating the rheological properties (workability, setting time), mechanical performance and printability of formulations incorporating secondary materials: Mg dross waste (up to 20 wt.%, replacing MgO), calcined sewage sludge (up to 10 wt.%, replacing KH₂PO₄), alternative fillers such as glass from municipal solid waste glass and from construction and demolition waste and ground blast furnace slag, benchmarked against volcanic ash. The baseline MKPC exhibited initial/final setting times of 34/109 min, good workability and compressive strengths of 29 MPa (1 day)/28 MPa (28 days). Optimal low-waste mixes (e.g., using municipal glass or 20 wt.% Mg dross) shortened the initial setting to 19–25 min (decreasing 24–42%), reduced the slump by 9–18% yet remained printable at laboratory-scale and achieved 1-day strengths >23 MPa/28-day >31 MPa (comparable or superior). Glass from municipal waste proved most promising, due to superior workability, lighter aesthetics and strength gains, supporting circular economy goals while substantially reducing material costs; higher waste levels compromised fluidity and buildability. Mineralogical analyses confirmed K-struvite formation alongside residual periclase, validating these formulations for upscaling sustainable 3D printing. Full article

Quaternary lavas (ankaramite, basalt, basaltic andesite, andesite, dacite) from the Kamchatka, Kurile, Ecuador and Cascade volcanic arcs contain Cl-bearing mineral microinclusions in rock-forming minerals and groundmass volcanic glass. They are represented by chlorargyrite (with a variable amount of native Ag), Cu, Ag, Sn, and Zn compounds with Cl and S, Sn- and Pb-Sb oxychlorides compositionally similar to abhurite and nadorite, as well as bismoclite and Cl-F-apatite. The Cl-bearing compounds with chalcophile metals are best approximated by mixtures of chlorargyrite with Cu sulfides, malachite, or azurite. Some Cl-bearing solid microinclusions in magmatic rock-forming minerals could have formed from Cl-rich melts exsolved from arc magmas during differentiation. Alternatively, specific magmatic microinclusions may record the decomposition of primary sulfides in the presence of Cl-bearing magmatic volatiles. Post-magmatic Cl microminerals found in fractures, pores, grain contacts, and groundmass glass are most probably precipitated from hydrothermal fluids accompanying their emplacement at the surface and post-eruption transformations in active fumarole fields. Assemblages of Cl-bearing microminerals with native metal, alloy, sulfide, oxide, and sulfate microinclusions in arc lavas potentially record late-magmatic to post-magmatic stages of formation of the epithermal and possibly porphyry mineralization beneath arc volcanoes. Full article

The Shawan Sag and its adjacent areas are rich in hydrocarbon resources. Moreover, the genesis and evolution patterns of zeolite cements in the sandy conglomerate reservoirs have resulted in diverse types of reservoir spaces, a complex composition, and significant heterogeneity. To investigate their impact on reservoir quality, this study integrates core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) for macro–micro comparative analysis of zeolite cement types, formation mechanisms, and pore systems in the Lower Permian strata of the Shawan Sag and adjacent areas. Research demonstrates that provenance exerts a control on type and origin of the diagenetic zeolites: In the Shawan Sag, zeolites form through hydration of volcanic glass in tuff, while adjacent areas develop zeolites via albitization of plagioclase derived from andesite. This genetic divergence drives pore differentiation: Zeolite (heulandite and laumontite) evolution in the Sag generates grain-edge fractures through cement volume shrinkage and crystalline water release. In contrast, the adjacent areas exhibit reservoir spaces dominated by dissolution pores, resulting from the dissolution of laumontite and calcite, along with a relatively higher overall rock porosity. Full article

This paper describes for the first time a lobe–hyaloclastite felsic complex on an oceanic island of intraplate setting. In the submarine volcanic succession of the Basal Complex of La Palma (Canary Islands), two main units are identified: an older felsic formation and a conformable upper basaltic–trachybasaltic formation. The felsic formation comprises three facies associations: (1) coherent facies, represented by trachytic lobes with porphyritic, aphanitic, or glass trachytes; (2) autoclastic facies, including hyaloclastites and autobreccias; and (3) syn-eruptive resedimented facies, consisting of mono- and polymictic breccias (massive or graded), and of volcaniclastic sandstones and breccias. The internal architecture and facies relationships are consistent with sedimentation in a submarine trachytic lobe–hyaloclastite complex, which predates the basaltic–trachybasaltic formation. These felsic rocks are classified as trachytes, although they exhibit extensive hydrothermal alteration. The behavior of incompatible trace elements suggests that the variety of the trachytic rocks—porphyritic or aphanitic terms—can be attributed to fractional crystallization processes. However, the features of the incompatible trace elements and the rare earth elements indicate that these trachytes are not cogenetic with the submarine basaltic–trachybasaltic rocks of the Basal Complex of La Palma. Instead, the trachytic magmas responsible for the lobe–hyaloclastite complex formation likely represent the late evolution of a precursor basaltic magma that would have led to the formation of a basaltic submarine shield not exposed nowadays. This study also presents the first robust geochronological constraints for the submarine volcanic units of the La Palma Basal Complex, based on U–Pb on zircons and Ar–Ar on amphiboles. Given that the submarine trachytic lobe–hyaloclastite complex is the oldest lithostratigraphic unit exposed on La Palma, a minimum age of 3.10 Ma is proposed for the initiation of the island submarine growth stage. Full article

While under-ice submarine hydrothermal systems provide critical insights into extremophile adaptations, the ecological impacts of explosive volcanism on these ecosystems remain poorly constrained. We successfully detected evidence of hydrothermal activities and explosive volcanism at 85° E, the eastern volcanic zone, ultra-slow spreading Gakkel Ridge. Hydrothermal plume, surface sediments, and volcanic glass samples were systematically collected to investigate the diversity of microbial communities. Our results revealed two distinct microbial regimes in hydrothermal plume: (1) chemoautotrophic bacteria (Sulfurimonas and SUP05_cluster), prevalent in global basaltic hydrothermal systems, potentially involved in carbon fixation through the CBB and rTCA cycles and (2) Alcanivorax (up to 82.5%), known for degrading hydrocarbons. Sediment profiles showed a depth-dependent decline of Alcanivorax, tightly coupled with TOC (1.05% to 0.45%, r = 0.75, p < 0.05). Additionally, the Alcanivorax MAGs demonstrated their potential in degrading various types of organic carbon, especially in alkane degradation. Strikingly, this pattern contrasts with hydrothermal plumes from effusive volcanic zones (Aurora and Polaris regions), where Alcanivorax was undetectable. We speculate that the surge of Alcanivorax in the 85° E hydrothermal plume was associated with the violent disturbances caused by explosive volcanism. This mechanism accelerates microbial-mediated carbon turnover rates compared to a stable hydrothermal ecosystem. Full article

Carbon isotopes in magmatic systems serve as powerful tracers for understanding magma evolution, mantle processes, the deep carbon cycle, and the origin of Earth’s carbon. This review provides a comprehensive overview of carbon isotope measurements and behavior in magmatic systems, highlighting recent technological advancements and scientific insights. We begin by examining methods for measuring δ¹³C in volcanic gases, vesicles, glasses, melt, and fluid inclusions. We then explore the behavior of carbon isotopes in magmatic systems, especially during magmatic degassing. Finally, we evaluate what recent advances mean for our understanding of the carbon isotope signature of the Earth’s upper mantle. Full article

Basalt is prevalent in the Earth’s crust and makes up about 90% of all volcanic rocks. The earth is warming at an alarming rate, and there is a search for a long-term solution to this problem. Geologic carbon storage in basalt offers an effective and durable solution for carbon dioxide sequestration. Basaltic rocks are widely used for road and building construction and insulation, soil amendment, and in carbon storage. There is a need to understand the parameters that affect this process in order to achieve efficient carbon mineralization. This review systematically analyzes peer-reviewed studies and project reports published over the past two decades to assess the mechanisms, effectiveness, and challenges of carbon mineralization in basaltic formations. Key factors such as mineral composition, pH, temperature and pressure are evaluated for their impact on mineral dissolution and carbonate precipitation kinetics. The presence of olivine and basaltic glass also accelerates cation release and carbonation rates. The review includes case studies from major field projects (e.g., CarbFix and Wallula) and laboratory experiments to illustrate how mineralization performs in different geological environments. It is essential to maximize mineralization kinetics while ensuring the formation of stable carbonate phases in order to achieve efficient and permanent carbon dioxide storage in basaltic rock. Full article

In this study, a chemometrics-assisted calibration method was developed for the Z-903 SciAps handheld Laser-Induced Breakdown Spectroscopy (h-LIBS) device. For this purpose, seventeen silica-based standard samples with known chemical composition were collected, pelleted, and analyzed using h-LIBS. Spectral data were pre-processed using a Whittaker filter and normalized via Standard Normal Variate (SNV). The dataset was divided into calibration and validation sets using the Kennard–Stone algorithm. Partial Least Square (PLS) regression was employed for multivariate regression analysis, and a variable selection method (i.e., Variable Importance in Projection, VIP) was applied to reduce the number of predictors. Results from the PLS-VIP approach demonstrated that this device is suitable for the quantitative measurement of nineteen chemical elements, including major and minor elements, achieving significant R² values for major elements including Na (R² = 0.91), Mg (R² = 0.95), and Si (R² = 0.89). The limits of detection reached are satisfying, being, for example, 0.24%, 0.41%, 0.43%, 1.5%, and 1.7% for Na, Al, Ca, Si, and Fe, respectively, among major elements, and 189 ppm, 165 ppm, 203 ppm, and 1 ppm for Ba, Cu, Mn, and Rb, respectively, among minor elements. Uncertainties in prediction of the element concentrations were compared with data from the literature, and the effect of another baseline pretreatment algorithm, airPLS (adaptive iteratively reweighted PLS), was also tested. The method was then applied to nine silica-based artifacts of different typologies sampled from the Archaeological Park of Tindari (Italy), including bricks from the theatre, archaeological glasses, and volcanic rocks. Full article

The 2014 Mt. Ontake eruption in Japan highlighted the need for improved volcanic shelters. To contribute to their reinforcement, this study focuses on the energy absorption characteristics of pumice, particularly artificial pumice made from waste glass. Compression tests were conducted under unconfined and oedometric conditions using a universal testing machine, drop-weight testing machine, and split Hopkinson bar across a wide strain rate range (10⁻³ to 10² s⁻¹). The deformation behavior was categorized into two types: one with a distinct initial peak followed by stress drop and another with a continuous transition to plateau deformation. Regardless of deformation type, the absorbed energy showed a positive dependence on strain rate. The average absorbed energy increased from approximately 1.6 MJ/m³ at 10⁻³ s⁻¹ to over 4.3 MJ/m³ at 10² s⁻¹. A simple predictive model was proposed to evaluate the energy absorption capacity of pumice reinforcement. The model’s predictions were in good agreement with experimental results for pumice layers up to 150 mm thick. These findings provide fundamental insights into the high strain rate behavior of artificial pumice and its potential application as a passive energy-absorbing material for impact-resistant volcanic shelters. Full article

Minerals have played a fundamental part in prebiotic chemistry on Earth, catalyzing the synthesis of inorganic and even organic molecules, including macromolecules such as RNA or DNA. Minerals based on silica are some of the first inorganics to be found in very ancient mineral fossils. These minerals or even volcanic glasses rich in silica, such as obsidians (a naturally volcanic glass, which is in fact an igneous rock), play an important role as supporting materials for obtaining the silico-carbonates of alkaline earth metals (usually called biomorphs). This is because, in most radiolarians, diatoms, and foraminifera, their external shells are made up of silica (SiO₂). However, it has yet to be evaluated whether the silica contained in the minerals present in the prebiotic era of the Earth interacted with the chemical elements that were also present during that era. To evaluate whether obsidian participated in the formation of the first inorganic structures of pioneering organisms, this study aimed to synthesize calcium and barium biomorphs on igneous rock and to show that dissolved organic and inorganic molecules might have interacted with the molecules of obsidian, producing a plethora of shapes that mimicked the cherts of the Precambrian. Full article

Tuffaceous fillings are a significant component of the Permian Kuishan sandstone in the North China Platform, and their complex diagenetic processes have a notable impact on the development of clastic rock reservoirs. This study, based on microscopic analysis of reservoirs and combined with quantitative analytical techniques such as electron probe microanalysis, homogenization temperatures of fluid inclusions, micro-area carbon-oxygen isotope analysis, and laser Raman spectroscopy, investigates the influence of tuffaceous interstitial material dissolution on reservoir development in the Permian Kuishan sandstone of the Gaoqing buried hill in the Jiyang Depression, Bohai Bay Basin. The results indicate that the dissolution intensity of tuffaceous interstitial materials can be classified into three levels: strong, moderate, and weak. In the strong dissolution zone, associated fractures and dissolution pores significantly contribute to reservoir porosity, with a positive correlation between dissolution plane porosity and total plane porosity. The reservoir space is characterized by a network of dissolution pores and fractures. The moderate dissolution zone is marked by the development of authigenic quartz, feldspar, and clay minerals, which do not effectively enhance porosity and permeability. The weak dissolution zone contains well-preserved volcanic glass shards, crystal fragments, and clay minerals, representing non-reservoir development sections. Lithology, sedimentary facies, diagenesis, and fractures collectively control the quality of the Permian Kuishan sandstone reservoir in the Gaoqing buried hill of the Jiyang Depression, Bohai Bay Basin. The advantageous zones for reservoir development in this area can be effectively predicted using thickness maps of the Kuishan sandstone, planar distribution maps of sedimentary facies, and fracture prediction maps derived from ant-tracking and coherence algorithms. Full article

This study explores the use of volcanic glass powder (VG) derived from Shirasu volcanic deposits as a substitute for silica fume (SF) in producing high-strength precast concrete piles with a compressive strength of 123 MPa. Initially, mortar specimens with varying VG replacement ratios and curing temperatures were prepared to assess their compressive strength. After identifying the optimal mix ratios and curing conditions for high-strength mortars, concrete specimens incorporating VG were produced. Subsequent testing revealed that a VG replacement ratio of 20% by cement volume and a curing temperature of 70 °C were optimal for achieving the target compressive strength. Although the Young’s modulus of VG-incorporated concrete was slightly lower than that of pure cement and SF concrete, its performance remained satisfactory. These findings suggest that VG is a viable alternative to SF in high-strength concrete applications, providing a sustainable method to enhance concrete properties using locally available volcanic deposits. Full article

The concept of the sustainable development of the world economy is currently aimed at achieving carbon neutrality, and this is due to the global warming of the planet. Energy and construction make a significant contribution to the release of carbon emissions into the environment and atmosphere. According to statistics, simply burning one ton of Portland cement clinker provokes the release of at least half a ton of carbon dioxide. In this study, the prepared samples were subjected to electron diffraction studies, as well as the X-ray phase analysis of the zone (XRF) using an ARLX’TRA diffractometer. Studies of macro- and microstructures were carried out using a Quanta 3D 200i scanning microscope. The obtained spectra were processed using EDAX TEAM software. The study of the microstructure of the samples showed that the bulk of the heterogeneous systems consisted of volumetric aggregates and intergrowths, i.e., small accumulations on their surfaces with pronounced cleavage, features of the microstructure indicating mineral formation processes. Therefore, the development of low-carbon construction models will make it possible to make a contribution and open an effective path to the implementation of climate policy through the rational use of natural resources and the involvement of industrial waste and nature-like technologies in the production process. In this regard, one of the options for solving the identified problems is to revise existing technologies and develop low-carbon, low-clinker binders using industrial waste and substandard raw materials. Full article

The present work describes the first results of the project “Lipari Obsidian and Neolithic Human Communities in the Aeolian Islands”, which aims to study the connection between obsidian sources on the island of Lipari and Neolithic populations on the Aeolian archipelago in Italy. Obsidian is a natural volcanic glass used to produce chipped tools; in the Neolithic period it was the sharpest known material and its trade played an important role in the Mediterranean area. It is thus of particular interest for tracing prehistoric trading patterns. Indeed, Lipari obsidian has a wide distribution and has been found even in southern France, Dalmatia, Sicily and mainland Italy. To reach the project goal, we considered both raw materials from different obsidian geological samples and artefacts from Neolithic settlements on the Aeolian islands, and performed fission-track dating (FT), a radiometric technique that can be used for uranium-bearing minerals and glasses. The preliminary results facilitated the age determination of geological samples, which we could relate to the different eruption phases. Archaeological samples were also dated; their link with the studied volcanic deposits and lava flows made it possible to shed some new light on raw material procurement and on the ability of the Neolithic populations to move from their locations, with particular attention to the consequences of environmental features on the first human settlements on the Aeolian islands. Full article