Mineral Systems Research Articles

Orogenic gold in the Blue Mountains, eastern Oregon, USA

At least 75% of gold produced in the State of Oregon came from the Blue Mountains. Most gold within the Blue Mountains was mined from orogenic gold veins and associated placer deposits. However, the geodynamic, regional, and deposit scale controls on orogenic gold mineralization within the Blue Mountains are not understood. Here, the mobilization, transport, deposition, and exposure of golds are linked to protracted tectonism of the western North American Cordillera through a scale-integrated mineral system. Gold production by mine (t) was estimated from public domain documents of production value (USD) and production time period (years). Lode endowment was then analyzed against criteria such as host rocks, vein structure, and location within the regional tectonic framework. Argillite, schist, and slate formed in accretionary wedge and fore-arc basins host the majority (∼60%; ∼29 t) of the total recorded gold production. Unique geochemical, geomechanical, and hydrological properties made these rock types excellent hosts. These properties were predetermined by both depositional setting (deep ocean basin) and metamorphic conditions (lower greenschist facies). Nearly half (50–55 %; ∼25.5 t) of recorded lode gold production was mined from lodes striking 030° ± 15° azimuth. A reconstructed paleo-stress field supports that these were left lateral faults. It is speculated that these were part of a margin-parallel shear zone that partitioned the strike slip component of oblique convergence between subducting oceanic plates and associated magmatic arcs. At both the district and the deposit scales, minor deviations in vein strike form local high-grade sites (i.e., dilatant zones). Such dilatant zones within major crustal shear zones could also explain the spatial, but not fluid-genetic association of granitic plutons with lode gold. The intersection lines between the veins, host rock fabrics, and secondary veins likely control the locations, thicknesses, and pitch of high-grade ore shoots.

Changes in Agrochemical Properties of Sod-Podzolic Soil and Productivity of Grain-Grass Crop Rotation Depending on Nutrients Balance

In a stationary field experiment on soddy-podzolic light loamy soil, the influence of fertilizer systems (organic, mineral, organo-mineral) and liming on the balance of nutrients, changes in the agrochemical parameters of the soil and the productivity of grain-grass crop rotation was studied. At the end of the 1st rotation of the five-field crop rotation, a medium-strength correlation (0.51) was revealed between the potassium balance and the change in its content in the soil, determined in an extract of 0.2 n. HCl (according to Kirsanov method). It was established that liming at 1.0 Ha of slightly acidic soil increased the productivity of crop rotation by 10%, which in turn led to an increase in the removal of nitrogen, phosphorus and potassium with crop yields by 10-14%. A positive balance of phosphorus was achieved only in the variant with an organo-mineral fertilizer system when applying manure and mineral fertilizers in full dose. It should be emphasized the need to take into account the return of nutrients with straw, in case of plowing in the field. It was revealed that in the organo-mineral fertilizer system, the share of biological nitrogen entering during the plowing of the clover layer is 26-28%, and about 20-23% more N is supplied during the plowing of straw. It was noted that when calculating the nitrogen balance, it is necessary to take into account its supply not only with mineral fertilizers, but also due to biological nitrogen fixation, when incorporating straw, etc. Failure to take into account these sources can lead to serious miscalculations. The organo-mineral system provided the highest productivity of the grain-grass crop rotation - 5.16 t of grain units/ha on an unlimed background and 5.73 t of grain units/ha with liming. On a slightly acidic background, the organic and mineral fertilizer systems ensured an equal crop rotation productivity of 4.28 t of grain units/ha, while liming had a slight advantage for the mineral system.

Strategies for Targeting in Undercover Terrains: Modeling Multi-Source Data in Apuí Region, SW Amazon Craton, Brazil

Exploring covered terrains is a challenge that requires the integration of multiple sources of knowledge, particularly in the initial stages of mineral exploration. The Apuí region, located in the Southwestern Amazon Craton, has a small and constant gold production, despite the deep cover and limited geological knowledge. The gold is mainly hosted in quartz veins and breccias that cut Paleoproterozoic volcano-sedimentary sequences. The occurrences have similar characteristics to magmatic–hydrothermal deposits, such as a lack of regional metamorphism and intense hydrothermalization. We undertook a multi-source prospective investigation on different scales using 2D and 3D techniques to translate the footprints of the mineral system into mappable criteria. Gold prospectivity maps for the Juma District and Guida Target were produced by integrating geological, geochemical, and geophysical datasets in knowledge-driven fuzzy systems. Regional airborne magnetization vector inversion (MVI) models were utilized. The correlation between the drill cores and the magnetic susceptibility models highlighted a potential surface for gold mineralization associated with the boundary between a granitic intrusion and volcano-sedimentary rocks. The prospectivity maps reduced the search area, and the regional susceptibility models allowed for the reconnaissance of structures and bodies that may be related to gold mineralization at depth. The results present new strategies for increasing discovery performance in the Southern Amazon Craton under cover.

Eutrophication of Arable Soil: The Comparative Effect of Mineral and Organic Fertilizer Systems

Agrogenic eutrophication refers to the artificial enrichment of soil with organic carbon and nutrients in result of applying mineral and organic fertilizers to increase soil fertility and plant productivity. Eutrophication of gray forest soils (Luvic Retic Greyzemic Phaeozems (Loamic)) was created by annual application of increasing doses of mineral (N 90–360, P2O5 75–300 and K2O 100–400 kg/ha) and organic (fresh cattle manure from 25 to 100 t/ha) fertilizers under plants of a 5–field crop rotation for 9 years in microplots experiment. The NPK amounts applied with the manure were approximately equal to the corresponding doses of mineral fertilizer. The rates of soil enrichment by Corg under mineral and organic fertilizer systems were, respectively, 0.29–0.38 and 0.76–1.56 g/kg per year, Ntot – 0.04–0.06 and 0.06–0.09 g/kg per year, available P2O5 – 4–57 and 11–55 mg/kg per year, available K2O – 5–44 and 6–31 mg/kg per year. The fertilizer doses under both systems were the most significant factor in the accumulation of nitrate nitrogen, available forms of phosphorus and potassium in the soil, while the Ntot contents was controlled by the duration of fertilizer application. The Corg content in the soil with organic and mineral fertilizers depended on the dose of manure and the duration of NPK application, respectively. Soil eutrophication with mineral fertilizers was accompanied by a decrease in soil pH, and eutrophication with organic fertilizers, on the contrary, led to an increase in pH. It is emphasized that over–fertilization and long–term use of fertilizers are the main factors in the development of soil eutrophication and the concomitant change in soil pH.

ОБГРУНТУВАННЯ НЕОБХІДНОСТІ СТАНОВЛЕННЯ ДЕРЖАВНОЇ ІННОВАЦІЙНОЇ СИСТЕМИ У СФЕРІ МОРЕГОСПОДАРЮВАННЯ

The article substantiates that the essence of competitiveness at the enterprises of the maritime complex lies in the strengthening of the process of global division of labor due to the interdependence of the macroregions of the globe, as well as in the structural disproportions of their development and the unevenness of the spatial distribution of the resource base in combination with environmental and other limitations. The protectionist steps taken by the maritime states with the aim of increasing the competitiveness of all types of maritime activities are analyzed. The main vectors of activities of international programs for achieving sustainable development, which provide for the prevention and reduction of the consequences of natural disasters and anthropogenic disasters in the World Ocean, the study of the role of the World Ocean, assessment, forecasting, mitigation and adaptation to variations and climate change, improvement of the management system of biological , mineral and energy resources of the World Ocean, improvement of management and protection of marine ecosystems. The article outlines that protectionist measures, such as cargo preferences and reservation of a large part of the cargo base for national shipowners, is a common international practice, characteristic of both leading maritime states and intensively developing coastal countries. It has been proven that the general increase in the need for mineral raw materials and the ever-increasing degree of depletion of its reserves on the continental part of the Planet led to the intensification of search and exploration work for highly liquid types of minerals, primarily oil and gas, on the continental shelf and oceanic slopes. In the article, it is determined that in the interests of increasing their own competitiveness, developed maritime states are conducting a course on anticipatory development of information support for maritime activities using modern means of navigation and communication. It has been analyzed that in our country there is an increasing disconnection of information support systems for maritime activities of the state, an insufficient level of their connection with international and global information systems and networks.

Eutrophication of Arable Soil: A Comparative Effect of Mineral and Organic Fertilizers Systems

Eutrophication of Arable Soil: A Comparative Effect of Mineral and Organic Fertilizers Systems

Potensi deposit wolfram di Indonesia

Bangka island is one of the islands in the Southeast Asian Tin Belt that makes Indonesia the largest tin (Sn) producer in the world. The carrier of wolframite is a by product mineral of the mineral tin (cassiterite). This study aims to study the presence and type of wolfram-as by product in the tin deposits on Bangka island. The research area was conducted on the eastern edge of Klabat Granite in Kepoh Village, Toboali District, South Bangka, at coordinates of 106o 31' 58" BT, 2o 56' 56 " LS. The result shows the presence of wolfram with grade of wolfram in veins reaching 8287 ppm. Wolfram was identified as an associated mineral in the tin mineralization system in Toboali along with rare earth metals (LTJ), molybdenum (Mo) and platinum (Pt). The results of analytical studies (UV, XRF, ICP OES, mineragraphy) on Toboali area minerals show the presence of wolfram in ores, concentrates, slag, and floor crusts. The identified wolfram minerals are wolframite (Fe.Mn)WO4 and scheelite (CaWO4) which are characterized through differences in properties such as color, fluorosence, magnetic, specific gravity and hardness values. The results obtained showed the presence of wolfram in Toboali area with wolfram content of 742 ppm in ore and also in the tin process, specifically in slag II of 1.02%. In addition, wolfram is indicated on the furnace floor and on the anode slime. Indonesia as one of the countries that owns wolfram minerals needs to continue the wolfram extraction process so that Indonesia receive the added value from its minerals.

Distribution of critical metals in evolving pyrite from massive sulfide ores of the Iberian Pyrite Belt

With >90 known deposits containing original reserves of >2400 Mt of sulfide ore, the Iberian Pyrite Belt (IPB) is the largest volcanogenic massive sulfide (VMS) province on Earth. In these evolving mineral systems, texturally different pyrite exhibits characteristic mineralogy and trace element fingerprints. Pyrite (Py-1), which is well preserved in the polymetallic ores that crystallized at the earliest stage of VMS deposit formation, consists of kernels of pyrite framboids surrounded by concentric colloform bands and ended by faceted outlines. It is rich in some metals like Pb, Zn, Sb and As (mostly hosted as nano-to-micron-sized particles, including galena, tetrahedrite and arsenopyrite) but depleted in Cu, Co and Bi. In contrast, pyrite from the pyritic and Cu-rich ore overprinted by late fluids exhibits spongy-looking (Py-2) or homogenous (Py-3) cores surrounded by external facets with crystallographic continuity across the whole single grains due to re-crystallization. Py-2 is depleted in most trace elements with the exception of Au and Bi, which occur both in solid solutions and as nano-to-micron-sized inclusions. Py-3 has the highest Cu, Ag, Co and Ni (mainly associated to nano-to-micron-sized particles of tennantite, chalcopyrite and gersdorffite) and the lowest Au contents in the form of native gold. The progressive increase in metal contents from inner to outer parts of Py-1 matches with the onset of the economic metal endowment of VMS deposits in the IPB, whereas Py-2 and Py-3 are associated with metal shoot processes that led to both leached and high-grade ores, very likely when mafic rocks were emplaced into the footwall of the deposits.

Productivity formation and processability of sugar beet in the conditions of continental climate

Purpose. To reveal the peculiarities of yield formation and processability of sugar beet roots in the conditions of the Steppe of Ukraine through optimizing the cultivation technology.
 Methods. The field experiment was conducted in the years 2020–2021 in the conditions of Chkalov Agrocompany LLC (Kirovohrad region). A drought-resistant diploid sugar beet hybrid ‘Magister’ (SESVanderHave) was grown against the background of the application of a moisture retainer (without hydrogel and hydrogel Aquasorb, 300 kg/ha) and different fertilization systems [without fertilizers – control; manure, 20 t/ha; N170P180K350; Leonardyt, 400 kg/ha; Parostok-20, 400 kg/ha]. Organic and mineral fertilizers (PK) were applied in autumn under plowing, while nitrogen component was applied under early spring cultivation. The adsorbent was applied to the soil two weeks before sowing the crop locally in the zone of the row to be, based on the data of the GPS tracker. The rest of the agricultural activities carried out were generally accepted components of cultivation technology in the research area.
 Results. As a result of rather difficult weather conditions in 2020, the yield of root crops was only 30.3 t/ha on average in the experiment. The lowest level yield (26.0 t/ha) was obtained in the plots of both controls without fertilizer, while the application of 20 t/ha of manure yielded 29.0–30.0 t/ha. The mineral system (N170P180K350), despite its significantly lower efficiency in the treatment without Aquasorb hydrogel (31.0 t/ha), when it was applied to the soil before sowing the crop, ensured the maximum productivity of sugar beets – 34.0 t/ha. In addition, against the background of the hydrogel, the effectiveness of Leonardyt and Parostok-20 increased significantly – yield increases by 7.0 and 6.0 t/ha, respectively. The maximum content of sugars in roots was noted under the mineral fertilization system against the background of Aquasorb hydrogel – 16.3 against 15.0% in the control. However, in the same treatment, the highest content of α-amine nitrogen was also obtained, which significantly reduces the yield of sugar at the factory. In 2021, due to favorable weather conditions during the crop vegetation, the yield of root crops was 55.6 t/ha on average in the experiment, which is almost twice as high as the previous year. As predicted, the lowest yield was obtained in the treatments without fertilizers – 49.7–50.2 t/ha, with manure application – 50.7–53.3 t/ha. Significantly higher, however, unlike in 2020, the indicators for the mineral fertilizer system were 56.9–58.1 t/ha. The most effective from the point of view of the formation of sugar beet productivity were Leonardyt and Parostok-20 yielding 58.1–58.6 and 59.2–61.6 t/ha, respectively. The maximum sugar content of roots was ensured by the use of Parostok-20 fertilizer, both on the background of Aquasorb hydrogel and without it (17.8% compared to control 15.8%).
 Conclusions. Weather conditions during the vegetation of sugar beets are the most significant factor that determines the level of their productivity, as well as the effectiveness of applied agricultural measures. In all treatments with fertilizers, a significant increase in crop yield was observed, and the amount of the obtained increments largely depended on both their type and the use of hydrogel, especially under unfavorable growing conditions. On average, during the research period, the highest indicators of sugar yield were obtained in the treatment with the use of organic fertilizers of the new formulation Leonardyt and Parostok-20 on the background of Aquasorb hydrogel, which indicates the feasibility of their further implementation in the cultivation technology for sugar beet.

Geochronology, geochemistry, and Sr–Nd–Hf isotopes of the Cretaceous igneous rocks in the Zhilingtou area, SE China, and their geological significance

The Zhilingtou deposit is one of the typical porphyry Mo deposits in South China. Disseminated and veinlet Mo ores occur in the roof pendant of the granite porphyry or the contact between the granite porphyry and the Badu Group gneisses, and some orebodies are cut by adamellite dikes. Here we present zircon LA–ICP–MS U–Pb dating yielding crystallization ages of 97 ± 1 Ma for the adamellite and 110 ± 1 Ma for the graniteporphyry. The adamellite and granite porphyry are metaluminous-peraluminous and belong to the high-K calc-alkaline-shoshonite type. They are characterized by high K2O, K2O + Na2O, FeOT, FeOT/(FeOT + MgO) and zircon saturation temperatures (784–817 °C); low MgO, TiO2, P2O5, Sr/Y and La/Yb values; enrichment in trace elements Rb, Th, U, La, Ce and other large ion lithophile elements; and depletion in Ti, Nb and P and other high field strength elements, revealing a highly fractionated A2-type affinity, formed in an extensional tectonic setting. The zircon εHf(t) values of the adamellite and granite porphyry range from −6.3 to −3.2 and from −10.0 to −4.1, respectively, with two-stage Hf model ages (TDM2 (Hf)) of 1559–1367 Ma and 1802–1430 Ma, respectively. The εNd(t) values of the adamellite and granite porphyry range from −19.0 to −11.5 and from −7.5 to −6.2, respectively, with two-stage Nd model ages (TDM2 (Nd)) of 2435–1835 Ma and 1522–1413, respectively, suggesting that they had mixed sources and were mainly formed by partial melting of a late Paleoproterozoic basement in the lower crust. In combination with previous studies, it can be concluded that after the Early Cretaceous, the subduction orientation of the Izanagi plate changed from oblique to parallel with respect to the continental margin, the slab rollback resulted in large-scale lithospheric extension and thinning, asthenospheric upwelling, and the basaltic magma underwent underplating and induced crustal melting, and finally formed the A-type granitic intrusions and related Mo mineralization systems.

Adsorption of the hydrophobic organic pollutant hexachlorobenzene to phyllosilicate minerals

Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the group of persistent organic pollutants (POPs) that can have harmful effects on humans and other biota. Sorption processes in soils and sediments largely determine the fate of HCB and the risks arising from the compound in the environment. In this context, especially HOC–organic matter interactions are intensively studied, whereas knowledge of HOC adsorption to mineral phases (e.g., clay minerals) is comparatively limited. In this work, we performed batch adsorption experiments of HCB on a set of twelve phyllosilicate mineral sorbents that comprised several smectites, kaolinite, hectorite, chlorite, vermiculite, and illite. The effect of charge and size of exchangeable cations on HCB adsorption was studied using the source clay montmorillonite STx-1b after treatment with nine types of alkali (M+: Li, K, Na, Rb, Cs) and alkaline earth metal cations (M2+: Mg, Ca, Sr, Ba). Molecular modeling simulations based on density functional theory (DFT) calculations to reveal the effect of different cations on the adsorption energy in a selected HCB-clay mineral system accompanied this study. Results for HCB adsorption to minerals showed a large variation of solid–liquid adsorption constants Kd over four orders of magnitude (log Kd 0.9–3.3). Experiments with cation-modified montmorillonite resulted in increasing HCB adsorption with decreasing hydrated radii of exchangeable cations (log Kd 1.3–3.8 for M+ and 1.3–1.4 for M2+). DFT calculations predicted (gas phase) adsorption energies (− 76 to − 24 kJ mol−1 for M+ and − 96 to − 71 kJ mol−1 for M2+) showing a good correlation with Kd values for M2+-modified montmorillonite, whereas a discrepancy was observed for M+-modified montmorillonite. Supported by further calculations, this indicated that the solvent effect plays a relevant role in the adsorption process. Our results provide insight into the influence of minerals on HOC adsorption using HCB as an example and support the relevance of minerals for the environmental fate of HOCs such as for long-term source/sink phenomena in soils and sediments.

Dichotomous Role of Humic Substances in Modulating Transformation of Antibiotic Resistance Genes in Mineral Systems.

Widespread antibiotic resistance genes (ARGs) have emerged as a focus of attention for public health. Transformation is essential for ARGs dissemination in soils and associated environments; however, the mechanisms of how soil components contribute to the transformation of ARGs remain elusive. Here we demonstrate that three representative mineral-humic acid (HA) composites exert contrasting influence on the transformation of plasmid-borne ARGs in Bacillus subtilis. Mineral surface-bound HA facilitated transformation in kaolinite and montmorillonite systems, while an inhibitory effect of HA was observed for goethite. The elevated transformation by HA-coated kaolinite was mainly attributed to the enhanced activity of competence-stimulating factor (CSF), while increased transformation by montmorillonite-HA composites was assigned to the weakened adsorption affinity of DNA and enhanced gene expression induced by flagella-driven cell motility. In goethite system, HA played an overriding role in suppressing transformation via alleviation of cell membrane damage. The results obtained offer insights into the divergent mechanisms of humic substances in modulating bacterial transformation by soil minerals. Our findings would help for a better understanding on the fate of ARGs in soil systems and provide potentials for the utilization of soil components, particularly organic matter, to mitigate the spread of ARGs in a range of settings.

The distribution of trace elements in sulfides and magnetite from the Jaguar hydrothermal nickel deposit: Exploring the link with IOA and IOCG deposits within the Carajás Mineral Province, Brazil

The Jaguar nickel deposit represents an important and unconventional discovery of hydrothermal Ni resources (58.9 Mt @ 0.95% Ni) associated with magnetite and apatite within the Carajás Mineral Province, Northern Brazil. The Jaguar deposit shares several similarities with iron oxide copper–gold (IOCG) deposits of the Carajás Mineral Province, especially regarding the structural control, and the hydrothermal alteration. Although IOCG and Kiruna-type iron oxide-apatite (IOA) deposits are closely associated in several geological provinces, this association has not yet been fully constrained in the Carajás Mineral Province. The Jaguar deposit occurs near mafic–ultramafic intrusions, along a regional fault zone, and is hosted either by granitic (northern portion) or felsic subvolcanic (southern portion) rocks. It is characterized by sub-vertical zones hosting a biotite-chlorite (Bt-Chl) hydrothermal alteration with ductile structures and disseminated sulfides (pyrite and millerite) and magnetite. These zones are overprinted by sulfide-magnetite-apatite-bearing breccias, which represent the main mineralization bodies. The sulfide assemblage in the mineralized zones is dominated by pyrite, pentlandite and millerite, with minor sphalerite and chalcopyrite.We have investigated the concentration of trace elements in the magnetite and sulfides from the host rocks, different alteration facies and the mineralization at the Jaguar deposit by LA-ICP-MS. Magnetite composition ranges from higher Al, Mn, Ti and V contents, for at least part of those in host rocks (granitic and felsic subvolcanic) and Bt-Chl alteration, into lower contents in the magnetite-apatite alteration, associated with the main Ni mineralization. Magnetite with higher Ti and V contents in host rocks is associated with discrete hydrothermal alteration pockets, have high Ni/Cr ratios and plot in high temperature hydrothermal fields in multi-element diagrams. Therefore, we support that these features are compatible with a hydrothermal origin. Anomalously high-Ni contents in magnetite point that the Neoarchean mafic–ultramafic layered intrusions of the Carajás Province represent potential Ni sources for hydrothermal remobilization. Anomalously high V contents in magnetite suggest lower fO2 conditions upon the formation of the deposit. The concentration of trace elements in magnetite associated with the Jaguar deposit is similar to those from other IOCG deposits from the Carajás Province (but with higher V and Ni contents), especially the Sossego mine in the Southern Copper Belt, indicating that it could represent a Ni-rich member of the regional-scale IOCG mineral system at Carajás. Pyrite and chalcopyrite have a composition similar to those from magmatic deposits, when using previously proposed discriminant diagrams, but this is also the case for other IOA and IOCG deposits. However, low PGE contents (Ru, Rh, Ir and Os) in pyrite from the Jaguar deposit support a hydrothermal origin. Our results highlight that the classifications provided by available discriminant diagrams are not unequivocal. We suggest that multi-element diagrams represent a complementary approach to binary plots and provide a more comprehensive classification for the use of indicator minerals.

Mapping Canada’s Green Economic Pathways for Battery Minerals: Balancing Prospectivity Modelling With Conservation and Biodiversity Values

Electrification of Canada’s energy and transport sectors is essential to achieve net-zero emissions by 2050 and will require a vast amount of raw materials. A large proportion of these critical raw materials are expected to be sourced from as yet undiscovered mineral deposits, which has the potential to accelerate environmental pressures on natural ecosystems. Herein we overlay new prospectivity model results for a major source of Canada’s battery minerals (i.e., magmatic Ni ± Cu ± Co ± PGE mineral systems) with five ecosystem services (i.e., freshwater resources, carbon, nature-based recreation, species at risk, climate-change refugia) and gaps in the current protected-area network to identify areas of high geological potential with lower ecological risk. New prospectivity models were trained on high-resolution geological and geophysical survey compilations using spatial cross-validation methods. The area under the curve for the receive operating characteristics (ROC) plot and the preferred gradient boosting machines model is 0.972, reducing the search space for more than 90% of deposits in the test set by 89%. Using the inflection point on the ROC plot as a threshold, we demonstrate that 16% of the most prospective model cells partially overlap with the current network of protected and other conserved areas, further reducing the search space for new critical mineral deposits. The vast majority of the remaining high prospectivity cells correspond to ecoregions with less than half of the protected areas required to meet national conservation targets. Poorly protected ecoregions with one or more of the five ecosystem services are interpreted as hotspots with the highest potential for conflicting land-use priorities in the future, including parts of southern Ontario and Québec, western Labrador, and northern Manitoba and Saskatchewan. Managing hotspots with multiple land-use priorities would necessarily involve partnerships with both Indigenous peoples whose traditional lands are affected, and other impacted communities. We suggest that prospectivity models and other machine learning methods can be used as part of natural resources management strategies to balance critical mineral development with conservation and biodiversity values.

Critical mineral constraints in global renewable scenarios under 1.5 °C target

To avoid catastrophic climate change, the world is promoting a fast and unprecedented transition from fuels to renewables. However, the infrastructures of renewables, such as wind turbines and solar cells, rely heavily on critical minerals like rare earths, indium, etc. Such interactions between climate targets, energy transitions, and critical minerals were widely overlooked in the present climate scenario analysis. This study aims to fill this gap through an introduction of metal–energy–climate nexus framework with its application on global energy transition towards a carbon-neutral (or below 1.5 °C) target, in which six state-of-the-art integrated assessment models (IAMs) under different shared socioeconomic pathways were applied. Our analysis revealed that climate mitigation is expected to boost significantly the critical mineral demand by 2.6–267-fold, which varies greatly by IAM models. Solar power development may be constrained by tellurium (Te) and selenium (Se) shortage, while wind power will be jeopardized by the limited scalability of rare earth production. Moreover, a more sustainable pathway may come at higher demand for critical minerals along with higher renewable ratios. Consequently, a holistic investigation of the interaction of mineral, energy, and climate systems is highly recommended for future scenario designing.

Synthetic magnetotelluric modelling of a regional fault network – implications for survey design and interpretation

The magnetotelluric (MT) method is increasingly being applied to mineral exploration under cover with several case studies showing that mineral systems can be imaged from the lower crust to the near surface. Driven by this success, the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is delivering long-period data on a 0.5° grid across Australia, and derived continental scale resistivity models that are helping to drive investment in mineral exploration in frontier areas. Part of this investment includes higher-resolution broadband MT surveys to enhance the resolution of features of interest and improve targeting. To help gain best value for this investment it is important to understand the ability and limitations of MT to resolve features on different scales. Here we present synthetic modelling of continuous, narrow, near-vertical faults 500 m to 1500 m wide with a resistivity 100–200 times less than the background rock resistivity using the ModEM software, and show that for such a situation a station spacing of around 14 km across strike is sufficient to resolve these into the upper crust. However, the vertical extent of these features is not well constrained, with near-vertical planar features commonly resolved as two separate features. This highlights the need for careful interpretation of anomalies in MT inversion. In particular, in an exploration scenario, it is important to consider that a lack of interconnectivity between a lower crustal/upper mantle conductor and conductors higher up in the crust and the surface might be apparent only, and may not necessarily reflect reduced mineral prospectivity.

Effects of a mineralization-promoting peptide on the physical and chemical properties of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) has been used widely in dentistry due to its sealing ability and biocompatibility. Delayed setting time is one of the major limitations of MTA. Various additives have been studied to further improve the properties of MTA with varied degrees of success. In this study, we have investigated the effect of a calcium phosphate mineralization promoting-peptide (MPP3) on the physical and chemical properties of MTA in comparison with Na2HPO4. Based on the reported effects of MPP3 on calcium-phosphate mineralization reaction, our hypothesis was that MPP3 may also show beneficial effects on the calcium-silicate mineralization system of MTA. Na2HPO4 was used for comparison since its setting accelerant effect on MTA has been well documented. The cements were prepared by mixing with distilled water, 0.40 mM MPP3 solution, 15% Na2HPO4 solution, and a combination of MPP3 and Na2HPO4 solution. Initial and final setting times were measured via Vicat needle. Microhardness values were measured via Vickers indenter at 1,3,7, and 28 days after hydration. Compressive strength after setting was measured via universal testing machine. Morphological and compositional analyses were performed via FESEM imaging, XRD and Raman spectroscopy. The microhardness data was evaluated via repeated-measures ANOVA. Setting time and compressive strength data were evasluated via one-way ANOVA. Initial setting time was reduced to ∼3 min in the Na2HPO4 containing groups but remained at ∼5 min in the control and MPP3 groups. Final setting times were significantly reduced in all groups compared to the control group. The reduction in the final setting times in the Na2HPO4 containing groups were significantly higher compared to the MPP3 group. Microhardness was significantly higher in the MPP3 group at all time points. No statistically significant difference in compressive strength was observed among the groups. FESEM analysis showed presence of ettringite crystals in the MPP3 group, and NaBiO3 crystals in the Na2HPO4 containing groups. XRD analysis showed a broadening of peaks at 2θ = 32° in the Na2HPO4 containing groups, possibly due to presence of NaBiO3. Raman spectroscopy showed statistically higher ettringite content in the MPP3 containing groups. Our findings indicate that MPP3 is a beneficial additive to eliminate some of the drawbacks associated with MTA with no detrimental effects on mechanical properties and without resulting in phases that potentially cause discoloration, such as NaBiO3. We propose that the reduced final setting time and increased microhardness by MPP3 may be associated with the increased ettringite content. Future studies, where wider range of MPP3 concentrations are studied may help elucidate and optimize the beneficial effects of MPP3 observed in this study.

Mineral potential modelling of orogenic gold systems in the granites-tanami Orogen, Northern Territory, Australia: A multi-technique approach

In this study we adopted fuzzy inference system (FIS), transformed predictor map-based random forest (RF) and feed-forward deep neural network (FF-DNN) approaches to mineral potential modelling (MPM) of the Granites-Tanami Orogen (GTO), Northern Territory, Australia, to (i) predict gold prospectivity, and (ii) compare the performance of these models to those previously generated in the study area. The current study, which utilized 19 predictor maps previously developed by Roshanravan et al. (2020) in the framework of a mineral systems approach, took into consideration the learnings gained and results obtained from previous approaches to modelling the gold potential of the GTO (Roshanravan et al., 2020: continuous fuzzy gamma, geometric average, data-driven index overlay and non-transformed predictor map-based RF; Roshanravan et al., 2021: cuckoo optimization algorithm). Importantly, our study area extending over > 46,000 km2 in the GTO, represents one of the few, if not the only, areas worldwide that has been subjected to eight different modelling techniques, an approach that delivered unique insights that cannot be achieved by utilizing a single technique. For example, our multi-technique approach enabled us to study what effect predictor maps may have on model performance and resulting mineral potential maps. In the case of data-driven MPM with RF, arguably-one of the most popular machine learning techniques, the effect of non-transformed (i.e., original) and transformed (i.e., derivative) predictor maps has never been evaluated simultaneously. To achieve this, we generated a transformed predictor map-based RF potential model with the aim of comparing it to the non-transformed predictor map-based RF model of Roshanravan et al. (2020). The FF-DNN and Mamdani-type FIS approaches to MPM were carried out specifically for the purpose of comparing and further investigating the modelling results. With respect to the Mamdani-type FIS, the concentration-area (C-A) fractal technique served to more objectively determine thresholds of the underlying mathematical functions, a novel approach that aids in reducing bias resulting from human input and expert opinion. The thresholded results demonstrate that the RF potential map generated with transformed predictor maps outperformed all other data-driven and continuous models. Overall, our multi-technique approach to MPM and the comparing and contrasting of a large set of resulting gold potential models, not only offered insights that helped to develop and calibrate new tools and techniques but also delivered what we believe are more robust gold exploration targets. As a result, we strongly recommend to using a multi-technique approach to MPM, which we hope will soon replace the currently accepted and widely utilized single-technique approach.

Mineral mapping in the Duolong porphyry and epithermal ore district, Tibet, using the Gaofen-5 satellite hyperspectral remote sensing data

Remote sensing technology is an exploration method that can directly map distribution of alteration minerals or zones associated with different types of mineral systems. Hyperspectral remote sensing can identify key pathfinder minerals and compositional variations within minerals. The Duolong porphyry-epithermal ore district, which has proven reserves of approximately 20 million tons of Cu and 420 tons of Au, is part of an emerging world-class metallogenic area in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet, China. The Gaofen-5 hyperspectral (GF-HS) reflectance data were used to map the distribution patterns of hydrothermal alteration and to locate areas potentially containing mineral deposits in the Duolong ore district (DOD). Based on the mixture tuned matched filtering (MTMF) technique and the absorption feature wavelength positions of the minerals, an alteration map was generated using GF-HS data for mineral mapping in the DOD with sparse vegetation. The widely distributed advanced argillic alteration (alunite + pyrophyllite + kaolinite ± dickite), phyllic alteration (high content of Al-rich white mica), propylitic alteration (Mg-rich chlorite), and limited argillic alteration (kaolinite ± dickite ± white mica) were mapped in detail. The distribution patterns of alteration in known deposits were fairly consistent with the mineralogical information obtained in previous studies. In addition, we identified potential mineralization areas with characteristics similar to the Duobuza, Bolong and Naruo porphyry deposits.

Effect of Co-Existing Cations and Anions on the Adsorption of Antibiotics on Iron-Containing Minerals.

The adsorption of antibiotics on minerals is an important process in their environment behavior. The adsorption behavior of antibiotics on iron-containing minerals and the effect of co-existing cations and anions were studied in this work. Magnetite, hematite, goethite and kaolin were selected as the representative minerals and characterized by SEM, XRD and BET. A total of eight antibiotics, including three quinolones, three sulfonamides and two mycins were chosen as the research targets. Results showed a higher adsorption amount of quinolones than that of sulfonamides and mycins on the surface of iron-containing minerals in most mineral systems. The adsorption isotherms of quinolones can be well fitted using the Freundlich models. The effects of five cations and five anions on the adsorption of quinolones were investigated, among which Mg2+, Ca2+, HCO3- and H2PO4- mainly showed significant inhibition on the adsorption, while the effects of K+, Na+, NH4+, Cl-, NO3- and SO42- showed less. Natural surface water samples were also collected and used as media to investigate the adsorption behavior of quinolones on iron-containing minerals. The buffering capacity of the natural water kept the reaction solution at circumneutral conditions, and the adsorption amount was mostly promoted in the goethite system (from 0.56~0.78 μmol/g to 0.52~1.43 μmol/g), but was inhibited in the other systems (magnetite: from 1.13~1.33 μmol/g to 0.45~0.76 μmol/g; hematite: from 0.52~0.65 μmol/g to 0.02~0.18 μmol/g; kaolin: from 1.98~1.99 μmol/g to 0.90~1.40 μmol/g). The results in this work help to further understand the transportation and fate of antibiotics in an aqueous environment.