Volcanic Material Research Articles

Soils in Understanding Land Surface Construction: An Example from Campania Plain, Southern Italy

The contribution of sediment transport and accumulation to soil formation was investigated in an area characterized by continental sedimentary activity since the Late Pleistocene. The area was the north-eastern portion of the large Quaternary graben represented by the Campania Plain, which is rimmed to the north–east–south by the Mesozoic carbonate Apennine nappes. The plain was filled mainly by products generated by eruptions from the Phlegrean Fields, which were also distributed on the slopes bordering the plain and remobilized toward the adjacent surfaces. Five sites were selected in the area in question. They were studied using morphological features and pertinent characteristics of the mineral soil fraction >2.0 mm, such as their volume and lithological description. Soils were compared to selected lithostratigraphic sequences characterizing the studied area, which were collected from literature and reinterpreted in pedological keys. The results showed that soils derived from the emplacement of Phlegrean primary volcanic materials, such as Campania Ignimbrite (~39–40 ky B.P.) and Neapolitan Yellow Tuff (~15 ky B.P.), with the related weathering products, and from volcanic materials reworked and transported by alluvial/colluvial episodes. The latter formed contrasting soil horizons which, differing in both rock fragment content and lithological composition, testified to the presence of lithological discontinuities. The formation of the horizons in question interrupted the genetic sequence derived from the in situ alteration of the volcanic substrata, suggesting that processes of transport and redistribution of sediments from the adjacent mountain slopes contributed to soil formation. The comparison of the pedostratigraphies with the lithostratigraphic sequences indicated a strong relation between geomorphic and pedogenetic events.

Discovery of a new volcanic soil material, "Akahoya," as an adsorbent for bacterial and viral pathogens and its application to environmental purification.

Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including Escherichia coli, Campylobacter jejuni, Vibrio parahaemolyticus, Salmonella Enteritidis, Staphylococcus aureus, Clostridium perfringens, spores of Bacillus subtilis and Bacillus anthracis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and Enterobacteriaceae as indicators of river contamination, as well as E. coli added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable E. coli continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of E. coli to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and Al2O3, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes.IMPORTANCEAlthough a safe and sufficient water supply is essential for the maintenance of hygienic conditions, a major challenge is to develop a comprehensive effective, sustainable, and cost-effective technological approach for the treatment and purification of contaminated water. In this study, we demonstrated that a novel volcanic soil, Akahoya, which has unlimited availability, is a highly effective adsorbent for a wide range of bacterial and viral pathogens, suggesting its potential as a sustainable resource for this purpose. It was suggested that the adsorption of microorganisms on Akahoya was mediated by phosphate groups present on the surface structures of microorganisms, which bind to the alumina component of Akahoya according to the phosphate concentration and pH of the liquid phase. The present findings highlight the exceptional ability of Akahoya to eliminate or reduce phosphate and microorganisms effectively in water purification processes, thus contributing to the development of efficient and sustainable solutions for addressing water pollution challenges.

Paleoenvironmental Transition during the Rhuddanian–Aeronian and Its Implications for Lithofacies Evolution and Shale Gas Exploration: Insights from the Changning Area, Southern Sichuan Basin, South-West China

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg2+ and SO42− for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target.

Implications of the eruptive behavior based on volcanic ash emitted during the 2015 activity of the Cotopaxi volcano, Ecuador

The glacial-peaked Cotopaxi stratovolcano in Central Ecuador became visibly active in 2015 for a duration of 101 days, when due to hydrothermal event significant amounts of volcanic particles together with gases precipitated in its surrounding. A detailed day-by-day sampling of these ash particles has led to a thorough morphological, mineralogical and geochemical evaluation in order to characterize the origin and the behavior of the volcano. The mostly trachy-andesitic samples lacked of juvenile material. All evaluated particles, minerals and lithics are of sharp, angular to subangular shapes. Discrimination diagrams and geochemical analysis evidenced a negative correlation between silica (SiO2) and sulfur (SO3), particularly on stronger eruptive occasions. The current study may serve for a general public awareness of volcanic behavior, as the results are able to evaluate and characterize the uprising degree of volcanic explosivity and range of associated hazards in this and similar volcanoes worldwide. Therefore, an immediate evaluation of such volcanic material will be able to result in calming the authorities and the public alike, allowing to offer an additional but decisive tool in the vigilance restless volcanoes.

Soil carbon stocks and nutrient stratification in a volcanically active coffee-dominated landscape in south-central Guatemala

The volcanoclastic mountains of Central America offer elevations ideal for coffee production. Both vulcanism and land use can have significant impacts on soil formation and properties. We evaluated how the interactive impacts of soil formation and coffee-dominated land use modulate soil storage and vertical distribution of organic carbon and nutrient elements in a volcanically active landscape dominated by coffee agriculture in south-central Guatemala. Thirty-seven pedons under coffee production (n = 29), forest cover (n = 5) and pasture (n = 3) were characterized and classified, and concentrations and stocks of organic carbon and macronutrient and micronutrient elements were quantified across genetic horizons. Additionally, soil organic carbon (SOC) stock values calculated using the fixed depth (FD) and equivalent soil mass (ESM) methodologies were compared. The active stratovolcano in the region had a strong effect on the development of andic properties and soil horizon burial, with thirty-one pedons classified as Andisols, three as Inceptisols and three as Entisols. Land use management practices and soil horizon burial by deposition of volcanic material were partly reflected in the vertical distribution of SOC concentrations and stocks. The vertical distribution of macronutrients was generally more sensitive to land use than the vertical distribution micronutrients, which could potentially reflect differences in inputs via fertilizers and vegetation cover and in outputs with biomass harvest. Soil organic carbon stocks were similar when calculated by FD and ESM, reflecting relatively consistent depth-wise bulk density. These results demonstrate that in volcanically active landscapes, land use should be considered in concert with soil-forming factors to comprehensively understand organic carbon and nutrient element storage in soils.

Analisis Pemberitaan Banjir Lahar Dingin di Sumatera Barat dalam Media Detik.com dan Antaranwes.com

News related to the cold lava flood disaster in West Sumatra that was broadcasted in print, electronic and online media became public consumption, causing perceptions in the community. Online media both Antaranews.com and Detik.com have news related to cold lava floods in West Sumatra. The media provided information from different perspectives in presenting the news. The floods came from material from Mount Marapi that erupted some time ago, most of which was on the slopes of the mountain. The material was washed away by rainwater downstream. Meanwhile, Antaranews.com provides information to the public by quoting the statement of Andalas University researchers that the accumulation of fallen tree material in the upper reaches of the Batang Anai river became a natural dam, due to the volcanic eruption of Mount Marapi accompanied by high rainfall as the cause of the collapse of natural dams and resulting floods. Framing analysis is viewed from syntactic, thematic, script and rhetorical structures. This research uses a qualitative approach with the theory of Zhongdang Pan and M. Kosicki. The results prove that the two online media have different points of view and news packaging, each emphasizing based on the data and facts received. After analyzing the two news articles, the researcher concluded that both news articles provided information on the causes of the flood disaster in West Sumatra. However, if seen in the Detik.com online media, the floods were caused by moderate to heavy rains that washed away volcanic material from the eruption of Mount Marapi in the form of cold lava. Another case with the information put forward by the Antaranews.com media that the flood was caused by the collapse of a natural dam in the upstream section of the Batang Anai river due to the vibration of the volcanic earthquake of Mount Marapi accompanied by high rainfall.

Characteristics of the Density and Magnetic Susceptibility of Pumice from the Maninjau Caldera-Forming Eruption, Indonesia

Abtract- Lake Maninjau is a volcanic caldera formed by a volcanic eruption located in West Sumatra. This volcanic eruption threw pyroclastic materials, one of which is pumice, as far as ± 75 km from the center of the eruption. This study aims to determine density and magnetic susceptibility characteristics of pumice from maninjau caldera-forming eruptions, indonesia. The method used is the rock-magnetic method. It is used to measure magnetic susceptibility based on the distribution of volcanic material. The samples were selected from 3 different locations around Mount Maninjau with distances varying between ±12-32 km. A Bartington Magnetic Susceptibility Metre Type B (MS2B) instrument was utilised to determine the susceptibility of rocks and X-ray fluorescence (XRF) to identify rock element levels. The results of the data analysis obtained have magnetic density and susceptibility values in the NGS (Ngarai Sianok) area, which ranged from 0.67-1.77×103 kg/m3 and 4.4-826×10-8m3/kg, the LBS (Lubuk Basung) area which ranged of 0.74-1.34×103 kg/m3 and 6.6-625.4×10-8m3/kg, and the PRM (Pariaman) area, which ranged from 0.68-3.63×103 kg/m3 and 8-359×10-8m3/kg. The results showed that when sampling closer to Mount Maninjau, the pumice is characterized by dense, fresh, but very small pore size and dominated by slightly greyish white pumice with few white crystals on its surface. Therefore, the location of the pumice from Mount Maninjau has a significant influence on its characteristics, including density, magnetic susceptibility, and iron (Fe) and titanium (Ti) content. Keywords: Pumice, Density, Magnetic Susceptibility, Mount Maninjau, XRF

Petrology and chronology of mare components in lunar basaltic breccia meteorite Northwest Africa 12384

AbstractNorthwest Africa (NWA) 12384 is a lunar polymict breccia composed almost entirely of basaltic components. The clast content includes low‐ to very‐low‐Ti volcanic picritic glass, basaltic vitrophyre, and crystalline pigeonite basalt—an assemblage of volcanic materials that can be tested for petrogenetic relationships. We present the inferred history of select mare components of NWA 12384 as suggested by texture, mineralogy, and petrography, and compare them to Apollo samples and other lunar meteorites. In addition, we used the volcanic glasses in the breccia as a primary composition for crystallization modeling and comparison to the lithic clast compositions. We find that the mafic clasts in NWA 12384 cannot be derived from the picritic glass through a common liquid line of descent because of higher Ti content, though they may have crystallized from a separate, common liquid line of descent. These clasts could represent local source‐region heterogeneity or differential assimilation of more Ti‐rich material. Pb‐Pb SIMS analyses of a large basalt clast in NWA 12384 reveal an age of 3044 ± 41 Ma (2σ), which is used together with the chemical data and 4π cosmic ray exposure age of less than 20 kyr and terrestrial age of between 3.1 and 17.3 kyr to constrain the possible locations of provenance for this meteorite.

The Impact of Flow Patterns Due to the Cold Lahar Flooding of Mount Semeru on the Collapse of the Bridge Connecting Malang District and Lumajang District

The flow patterns that occur in rivers as a result of falling cold lava often cause damage here and there. This incident cannot be separated from the large volume of water mixed with material that crosses the open channel which is caused by input water supply or water supply from river reservoirs crossed by cold lava. by water researchers for water mixed with volcanic eruption material suspended above. The event of water flowing through a river is influenced by the presence of the surface profile of the river bed and the various widths of the river that occur. If a volume with a certain viscosity is given, a thick flow will be formed that can be seen on the surface of the river, while that which is not visible to the naked eye above the water surface is called thick viscosity. If the runoff of cold lava material that occurs in the channel is not measured, it will result in wild jumps. The wild and viscous jumping structure that has been arranged can be observed as to how the flow pattern occurs. To avoid not detecting the flow pattern, water measuring structures are needed, one of which is a threshold with openings below or what is known as flow above the threshold along with existing bridge buildings around it. This sluice gate is easy to operate manually. The need for water operations with excess water availability is not an easy thing to calculate, because of the influence of depth and jumps that occur around the bridge, hydraulic jump patterns often ignore this measurability, this will be an obstacle if there is a large supply of cold lava. mixed with rainwater during peak conditions in the drainage process. Observations of this completion need to be proven by carrying out model tests using a tool known as the Threshold which produces a water jump along with the material. This requires further investigation for research in the model channel. For modeling thresholds and bridges connecting between plains, this tool provides instruments and many threshold treatments as well as regulating pressurized water with a pump at a certain flow rate in a measurable manner. To analyze the height of building damage, determine the flow pattern, speed by observation, test results with valve openings on certain pumps, researchers tested and measured the position of cold lava deposits one by one, the position of the slope of the river in certain sections, starting with an opening of 0.5; 0.75, read the instrument, move the threshold position from a bridge distance of 20 cm, 40 cm, to the furthest distance of 240 cm. Make graphs of test results for the threshold of the bridge opening transfer tool by testing the tool and opening 3 times for each pump opening, recording, mapping the depth values, jump length and travel time of the instrument on the test tool. Recommend the results of the analysis of the Threshold and Bridge tests to provide information to bridge construction planners that the test results with various threshold positions in certain conditions have the value of the Glidik II bridge collapse, the jump with the travel time of the speed of passing cold lava. Next, the bridge is determined and the next threshold can be used to determine how severe the damage is to the river. This research is laboratory research with threshold and bridge models. The target of this output is a journal article resulting from a simulation of determining the flow pattern that occurs in the channel by shifting the position of the threshold relative to the location of the bridge from the channel model with various diameter sizes of the model material, the results of which are in the form of a table and graphed on the part modeled in the water laboratory, especially flow with sediment and cold lava material. The results of this section were observed up to the collapse of the bridge at a depth of 4.5 cm with an opening of ½ second to 37 (on the model scale) observed or a depth of 45 meters (on the empirical scale). to then be written in the form of an article to be included in an international journal.

Enrichment Characteristics and Mechanisms of Lithium, Gallium, and Rare Earth Elements (REY) within Late Permian Coal-Bearing Strata in Wanfu Mine, Xian’an Coalfield, Guangxi Province, Southwest China

The study of lithium (Li), gallium (Ga), and rare earth elements (REY) within coal-bearing strata represents a cutting-edge concern in coal geology, ore deposit studies, and metallurgy research. With the rapid advancement of technology and emerging industries, the global demand for Li-Ga-REY has significantly escalated. Several countries worldwide are facing immense pressure due to shortages in Li-Ga-REY resources. Coal-associated Li-Ga-REY depositions have emerged as a pivotal direction for augmenting Li-Ga-REY reserves. To ascertain the enrichment distribution patterns and genetic mechanisms of Li-Ga-REY within the coal-bearing strata of the late Permian Heshan Formation in Wanfu mine, Xian’an Coalfield, Guangxi Province, this study carried out comprehensive testing and analysis on Li-Ga-REY enriched in the mineralized layers within the strata. The Heshan Formation in Wanfu mine presents four layers of Li-Ga-REY-enriched mineralization, labeled from bottom to top as mineralized layers I, II, III, and IV, corresponding to coal seams K5, K4, K3, and K2. These critical metals are predominantly hosted within clay minerals (kaolinite, illite/smectite, and chlorite). The enrichment of critical metals within the Heshan Formation is closely related to terrigenous detrital materials from the Daxin paleocontinent, volcanic detrital materials induced by the Emeishan mantle plume and the Yuenan magmatic arc. The accumulation of Li-Ga-REY and other critical elements within the mineralized layers is the result of inputs from terrestrial and volcanic detrital sources, interactions between peatification and diagenesis stages, and occasionally the input of metal-enriched fluids. In the mineralized layers I, II, and III, the content of lithium oxide (Li2O) surpasses the boundary grade, and the levels of REY, Ga, and (Nb,Ta)2O5 are close to boundary grades, indicating promising exploration prospects. The Wanfu mine in the Xian’an Coalfield can be considered a primary target zone for the exploration and development of coal-associated critical metal resources in Guangxi.

Insights Into a Correlation Between Magnetotactic Bacteria and Polymetallic Nodule Distribution in the Eastern Central Pacific Ocean

AbstractThe Clarion–Clipperton Fracture Zone (CCFZ) in the eastern central Pacific Ocean is the world's largest area for potential deep‐sea polymetallic nodule mining and is attracting increased scientific and commercial interest. Recent studies indicate that biogenic magnetite, generated intracellularly by magnetotactic bacteria (MTB), can carry a biogeochemical remanent magnetization in polymetallic nodules, although whether biogenic or physical‐chemical processes are responsible for nodule formation remain poorly constrained. Here, we report a combination of magnetic, electron microscope and geochemical analyses on seafloor surface sediments from the eastern CCFZ to understand the spatial distribution of biogenic magnetite and possible relationships between MTB and polymetallic nodules. Experimental results indicate that sedimentary magnetic minerals from the northern and southern regions are dominated by detrital (eolian loess and volcanic material) and biogenic magnetic minerals (magnetosomes), respectively. Sediments from the intermediate region contain both detrital and biogenic magnetic minerals. Quantitative first‐order reversal curve‐principal component analysis indicates that biogenic magnetite has the highest concentration in the intermediate CCFZ region, coincident with the highest polymetallic nodule density. Combined with previous research, we speculate that MTB growth on the CCFZ seafloor is driven mainly by local redox conditions. Manganese nodule surfaces are rich in organic biofilms, which results in a relatively thick oxic‐anoxic transition zone in high‐abundance manganese nodule regions, which generates an optimal microenvironment for both MTB growth and magnetite biomineralization. This study provides new clues for understanding the ecological distribution of MTB and the biogeochemical remanent magnetization recorded by biogenic magnetite in deep‐sea sediments.

Investigation of properties of SCC with perlite as a partial replacement of coarse and fine aggregate

Abstract Self-compacted concrete, is an extremely flowable concrete that can spread readily into formwork without any void and solidify without showing signs of bleeding or segregation when there is no vibration. The effects of using Perlite material as a partial replacement of aggregate on the fresh and hardened characteristics of self-compacting concrete have been examined in this study. Perlite material, is alumino-siliceous amorphous volcanic material that occurs naturally and is derived from crude perlite rock is utilized in construction Its high porosity and low density make it a great option for a lightweight mineral filler in a variety of applications. In order to do this, the mixing procedures maintained at constant ratio of water to cement and super plasticizer, and perlite was substituted at varying volume percentage (20, 40, and 50) %. Concrete’s flow ability, passage ability, and resistance to separation were examined using performance tests such the V- funnel, Slump flow, L- box tests and Segregation Index. The findings revealed that when perlite was substituted for coarse aggregate and fine aggregate in the observe concrete, the workability reduced. This study has looked into the mechanical characteristics of hard self-compacting concrete as well. For this reason, a series of tests were conducted, including ones measuring thermal conductivity and density at 28 days. compressive, splitting, and flexural strength at ages 7, 28, and 56 days. By increasing the percentage of perlite the values of (compressive strength, flexural strength and splitting tensile strength) decreased significantly compared with reference mixture (0% perlite replacement). The highest decreased was at 50% perlite replacement of aggregate.

Etna volcanic ash as new sustainable supplementary cementitious material

The use of supplementary cementitious materials (SCMs) is one of the fundamental pillars in the transition towards sustainable binders, and the seek for new alternative SCMs is becoming more and more important to front, on one hand, the increased request, and the expected future shortage of some existing SCMs, such as blast furnace and steel slag, on the other. In this work the use of volcanic ash as a pozzolanic constituent in the manufacture of a type IV mixed cement has been explored. Thousands of tons of ash are erupted for each Strombolian event from the volcano Etna (Italy) . The periodicity and magnitude of the events is variable but very often impressive. In the year 2021 alone, 51 significant paroxysmal events occurred. The enormous quantities of material removed from urbanized areas constitute a valuable resource that can be reused instead of being disposed of as waste. The experimental results of the tests carried out for the physical, mechanical and chemical characterization of the new mixed cement showed that the volcanic material meets the requirements dictated by the standard EN 196-5 to assess pozzolanic properties, and can be effectively used in the production of commercial pozzolanic cements as a partial, or even total replacement for the natural pozzolans. These findings are fundamental to encourage the start-up of a production chain aimed at recycling the waste eruptive material of volcanoes that insist on urbanized areas. Moreover, a review of the regulative framework concerning test methods assessing the pozzolanicity of volcanic material is given.

Comparative study of various volcanic materials as fillers in polymer composites

Comparative study of various volcanic materials as fillers in polymer composites

Formation mechanism and implication of analcime in the sandstone reservoirs of the Permian Jingjingzigou formation in the Jinan sag, southern Junggar basin, NW China

Analcime plays a significant role in sandstone reservoirs as an authigenic diagenetic mineral in the Junggar Basin (northwestern China). However, the origin and controls on the reservoirs have received remarkably little attention. This study investigates the formation mechanism of analcime in the Middle Permian strata in the Jinan sag (southern Junggar Basin) through petrography and geochemistry. The results show that analcime is formed through early alkaline hydrolysis of volcanic materials under specific temperature and pressure conditions. The reservoir rocks primarily consist of various lithic sandstones, including volcanic debris such as basalt, andesite, and tuff. Analcime is characterized as rich in aluminium and poor in sodium, classified as low-silica analcime with a low Si-Al ratio (1.98–2.38). Furthermore, various other diagenetic minerals, such as glauconite, chlorite, albite, and calcite have been identified. The primary reservoir space chiefly consists of intragranular dissolved pores of analcime, while secondary pores are formed by intragranular pores of feldspar and lithic, along with some remaining intergranular pores. Cementation of analcime during early diagenesis changes primary pore structures and reduces reservoir properties. The low-silica analcime dissolves due to acidic pore fluids associated with three stages of oil and gas charging, transforming into albite and creating numerous secondary pores, thereby enhancing reservoir quality.

Insights into alkali and acid-activated volcanic ash-based materials: A review

This review provides a comprehensive study of the fundamentals of the alkaline and acid activation of volcanic ashes (VA), for mainstreaming their use as a conventional feedstock for developing geopolymers and their applications. The low reactivity in an alkaline environment is driven by the low content of the amorphous phase and the low solubility of iron, calcium and magnesium at pH > 12. Nevertheless, techniques such as mechanochemical activation has significantly improved the reactivity and the properties of the resulting products. In the acid phosphate medium, the high solubility of iron, calcium and magnesium ensures good reactivity and a high reaction rate at room temperature. As a result, the engineering properties of acid-phosphate-activated volcanic ash are superior to those of alkali-activated volcanic ash. The resulting materials have great potential for use as binders in concrete design, for the stabilization of compressed earth bricks and for the rapid repair of deteriorated concrete structures. However, significant research is required to fully understand their durability performances, life cycle and techno-economic viability for large-scale utilisation. Further, the limited availability of phosphate resources makes acid activation not a viable route to activate volcanic ash for building purposes. The acid-activated volcanic ash has potential in waste management applications such as nuclear waste or heavy metal encapsulation. Finally, volcanic ash emerges as a promising raw material for developing sustainable building materials through alkali and acid activation. This holds as its exploitation is non-disruptive, and processing requires less energy compared to calcined clay or fly ash.

Empirical Model of Unconsolidated Tephra Erosion: Verification and Application on Micro Catchment

Erosion is an important process that shapes the earth's surface. Given the complexity of the process, efforts to understand it are essential. Over the last 50 years, numerous models of soil particle erosion by surface runoff emerged, some of which share similar forms and parameters. The differences lie in the coefficient values of the parameters, attributed to the characteristics of the soil material such as texture, structure, and organic matter content. However, these erosion models tend to underpredict in the case of new volcanic deposit erosion. The erosion model for unconsolidated tephra, proposed by Yunita, was developed through laboratory experiments using volcanic material from Merapi Volcano, Indonesia. Nevertheless, the model has not been implemented for other cases. Therefore, this study aims to verify the erosion model for volcanic material in other cases, explore the possibility of broader implementation, identify the factors that influence its accuracy, and determine the model’s limitations. To verify the model’s potential for broader application, we applied it to micro-scale catchments in St. Hellens (USA), Sakurajima (Japan), and a laboratory scale plot in Merapi (Indonesia). The verification yielded satisfactory results for all three cases, especially for new tephra deposits. In the case of St. Helens, the extrapolation of model coefficients was proven to still be applicable even for thicker tephra layers. However, the erosion prediction was overestimated for tephra layer deposits older than 1 year, as the erosion rate decreases over time due to the compaction and stabilization of the tephra layer. In the Sakurajima, the model was also suitable for predicting long-term erosion amounts (daily and monthly). Meanwhile, in Merapi, the model provided accurate predictions for slopes of 20º and 25º but was less accurate for 30º slopes, where the measured erosion was due to both erosion and slope failure. These verification results demonstrate the potential of applying the empirical erosion model to micro catchments with relatively homogenous slopes and tephra properties. The sensitivity test revealed that slope, runoff, rainfall intensity, and volcanic ash thickness are strongly influence the erosion rate. This study also simplified the volcanic ash erosion model as a function of slope (S0), runoff (q), and rainfall (i) by assuming the value of (1-τc/τ0) is equal to 1. Further study using GIS tools is required for its application on several catchments with heterogeneous characteristics. Doi: 10.28991/CEJ-2024-010-07-02 Full Text: PDF

THE BABYNSKA SUITE TUFFS OF THE CONTINENTAL FLOOD BASALTS OF WESTERN VOLYN: MINERALOGY, PETROGRAPHY, PETROCHEMISTRY, GENETIC AND APPLIED SIGNIFICANCE

According to the data of comprehensive precision research, the spatial distribution and mineral composition were revealed, the petrographic and petrochemical features, and the genetic and practical significance of the Babynska effusive-pyroclastic suite tuffs of the continental flood basalts of Western Volyn were clarified in connection with the copper content. The thicknesses and hypsometry of the relief of the paleosurface of the pyroclastic formations of the Babynska suite were analyzed and the important elements of its vertical and lateral structure (by area) were clarified, the real picture of which is reflected in the constructed maps of the thicknesses and relief of the paleosurface of the pyroclastic formations of the suite, in particular, on the Ratnе–-Kamin-Kashyrsk Area. The formation of the Babynska suite tuffs in the regime of gravitational deposition of pyroclastic material with the accumulation of tuff deposits at the stage of incomplete solidification of volcanic material and the formation of coarse, non-rhythmic layering, without clear signs of redeposition, i.e. of volcanomictіс origin, has been proven. Differences in the mineral composition and petrochemistry of tuffs of different colors: gray-green and red-brown were found. Emphasis is placed on the enrichment of native copper in tuffs of gray-green color and possible explanations for this correlation are proposed. The obtained results from a genetic point of view provide important information for paleovolcanogenic and paleogeographical reconstructions, in practical terms they contribute to the improvement of the copper bearing prospects of volcanogenic layers of the continental flood basalts and can be proposed for use by production organizations of the geological profile.

Mineralogy and Selenium Speciation Analysis of Early Cambrian Selenium-Rich Black Shale in Southern Shaanxi Province, China

Selenium (Se) is an essential trace element for humans and animals, and an excess of or deficiency in Se is harmful to health. Research on the selenium enrichment zone began in the late 1970s in Shuang’an, Ziyang, southern Shaanxi Province. Naore village is only one selenosis area in Shuang’an, Ziyang, China. Different scholars have conducted systematic studies on the occurrence of selenium, its organic geochemistry and biomarkers, and its content and enrichment patterns in this area. This study applied the TIMA (TESCAN integrated mineral analyzer) for the first time to conduct detailed mineralogical work. The minerals included quartz, carbonate minerals (calcite and dolomite), feldspar (plagioclase, albite, and orthoclase), biotite and muscovite, clay minerals (chlorite and kaolinite), hematite, pyrite, and accessory minerals (almandine, olivine, zircon, and apatite) in Naore village, Ziyang, Shaanxi Province. The ATi index (100 × apatite/(apatite + tourmaline)) is used to determine the source of heavy minerals and the degree of heavy minerals’ weathering. The content POS (100 × (pyroxene + olivine + spinel)/transparent heavy mineral) of olivine, pyroxene, and spinel in heavy minerals can reflect the contribution of basic and ultrabasic rocks in the source area. The ATi and POS indexes for the heavy minerals in the research area were 91.83~99.96 and 0.01~18.75, respectively, reflecting the abundance of volcanic rock material in their source. In addition, the migration, transformation, bioavailability, and toxicity of selenium in the environment are closely related to its species. The species of selenium in various selenium-rich areas (Naore, Wamiao, and Guanquan) mainly include unusable residues and organic forms, followed by humic-acid-bound selenium. The proportions of water-soluble, exchangeable, and carbonate-bound selenium are relatively small, and the proportion of Fe-Mn oxide-bound selenium is the lowest.

Study on the preparation, performance, and mechanism for solid waste cementitious materials

Using granulated blast furnace slag (GGBS) as the volcanic ash material and fly ash (FA) as the supplementary material, the study was conducted to investigate the mix proportions of an alkali-activated solid waste cementitious material under the stimulating effect of alkali activator carbide slag (CS). This type of cementitious material could serve as a substitute for a portion of cement usage, contributing to resource conservation and mitigating environmental pollution caused by solid waste. This facilitates green and sustainable development. Firstly, an analysis of three raw materials was conducted, and the mix proportions were designed with reference to the CaO-Al2O3-SiO2 system of Portland cement. Then 28 groups of specimens were prepared based on the designed mix proportions. The flowability and setting time of each group of specimens were tested. It was observed that an increase in the amount of CS and a decrease in the amount of GGBS resulted in decreased flowability and earlier setting times of the specimens. Additionally, FA exhibited a retarding effect on setting time. Compressive strength tests were conducted on these specimens, revealing that the optimal CS content ranged between 20 % and 40 %. Overall, FA had minimal impact on compressive strength, but it contributed to increased compressive strength in the specimens at later ages. Subsequently, microscopic characterization of the hydration products was performed using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Differential Thermal Analysis (DTA), Scanning Electron Microscope (SEM), and Energy Dispersive Spectrometer (EDS). The hydration products were identified as predominantly composed of calcium silicate hydrate. The quality and defects in the microstructure of gel products from various specimen formulations were compared to elucidate differences in macroscopic performance. Finally, the hydration process mechanism diagram of alkali-activated materials was presented to illustrate the stimulation and formation of gel products, primarily composed of C-S-H. This diagram revealed the principles behind the action of alkali-activated cementitious materials. The proposed design and testing methodology for the GGBS-FA-CS system in this study had certain reference significance for research in the direction of alkali-activated solid waste cementitious materials.