Pb Ore Research Articles

The environmental fate of metals from zinc and lead mining area in surface water (Przemsza River, southern Poland)

The chemical composition of surface waters of the Przemsza River flowing through Upper Silesia (in southern Poland) is strongly affected by Zn and Pb ore, and less by Carboniferous hard coal deposits. The chemical type of surface water is Ca-HCO3. In the waters, three groups of metals and metalloids were found that directly interfere with the mineralization of the deposit. Although genetically related to the same deposit, each group exhibits a different fate in the environment. A typical deposit association is Pb-Zn-Ag-As-Sb-Hg. The first group of metals in surface waters is consistent with the typical association of the ore Zn-Pb-Cd-(Tl), the second includes Ag-Sb-Hg, and the third includes the additives in the zinc and lead ore Co-Ni-Mo-Mn:[(Ca↔Na)+(HCO3↔Cl)]+[(Zn-Pb-Cd-(Tl))+(Ag-Sb-Hg)+Co-Ni-Mo-Mn)].Depending on the pH-Eh conditions, metals and metalloids precipitate out of the solution or sorb on solid particles. The concentrations of individual groups of metals are interdependent but show different environmental fates along the river course. The natural process of the enrichment of surface waters with Zn-Pb-Cd-(Tl) is by water circulation in a rock matrix naturally rich in the metals and draining groundwaters by the river. Under oxidizing and slightly alkaline conditions, Ag-Sb-Hg incorporated into the soluted chemical compounds, may, when the physicochemical parameters of the waters change, be adsorbed and/or precipitated. The presence and ratio of concentrations of Co-Ni-Mo-Mn with respect to zinc are almost identical, differing only in concentration.

Applications of Pb isotopes in granite K-feldspar and Pb evolution in the Yilgarn Craton

The isotopic composition of Pb in a mineral or rock at the moment it formed – often referred to as common Pb – provides an important tool to track geological processes through time and space. There is a wide range of applications of common Pb isotopes including understanding magma sources, melt production, fractionation, contamination, and crystallization in the crust. Pb but not U is incorporated into the structure of K-feldspar during crystal growth, which, together with its widespread occurrence as a framework mineral, makes it an excellent common Pb tracer. Consequently, common Pb isotopes in granite K-feldspar crystals provide a potential signature of source composition and a link to crustal growth processes in the mid to lower crust. Hence, combining common Pb isotopes with Sm-Nd (or Lu-Hf) isotopic signatures from the same dated rocks allows assessment of the degree of isotopic communication from deep fractionation systems to those higher in the crustal column. In this contribution, we analyze common Pb isotopic signatures in K-feldspar from a granite sample transect through the Archean Yilgarn Craton in Western Australia. This transect crosses the major crustal-scale Ida Fault that is apparent on Nd and Hf isotopic maps and interpreted as a fundamental lithospheric boundary across which magma sources change. Our results yield a difference in median values of the Pb isotope derivative parameters µ (238U/204Pb) and ω (232Th/204Pb) across the Ida Fault, with higher µ and ω associated with more evolved Nd and Hf isotopic signatures on the western side of the fault. Pb evolution in the Yilgarn Craton is distinct from the widely applied Stacey & Kramers (1975) model. New Yilgarn-specific Pb evolution models are developed with implication for common Pb correction. A correlation in the spatial trends of granite K-feldspar common Pb signatures with those of upper crustal Pb ores and also the Sm-Nd and Lu-Hf systems reveals geochemical communication all the way through the crustal column, implying a common source for the entire lithospheric section on each side of the Ida Fault. Pb isotopes in granite K-feldspar are not an independent geochronometer but may yield important source context on major phase silicate growth that helps refine U-Pb geochronology interpretations (e.g., distinguishing magmatic versus metamorphic zircon growth).

Spatial distribution and composition of mine dispersed trace metals in residential soil and house dust: Implications for exposure assessment and human health

Trace metal exposure from environmental sources remains a persistent global problem, particularly in communities residing adjacent to metal extraction and processing industries. This study examines front yard soil and house dust from 62 residences throughout the Australian Ag–Pb–Zn mining city of Broken Hill to better understand spatial variability in metal distributions, compositions and exposures across an industrially polluted urban environment. X-ray fluorescence analysis of paired soil/dust samples indicated that geomean concentrations (mg/kg) of Cu (32/113), Zn (996/1852), As (24/34) and Pb (408/587) were higher in house dust while Ti (4239/3660) and Mn (1895/1101) were higher in outdoor soil. Ore associated metals and metalloids (Mn, Zn, As, Pb) in soil and house dust were positively correlated and declined in concentration away from mining areas, the primary source of metalliferous emissions in Broken Hill. The rate of decline was not equivalent between soil and house dust, with the indoor/outdoor concentration ratio increasing with distance from mining areas for Zn/Pb (geomean = 1.25/1.05 (<1 km); 2.14/1.52 (1–2 km); 2.54/2.04 (>2 km)). House dust and Broken Hill ore Pb isotopic compositions (206Pb/207Pb; 208Pb/207Pb) were more similar in homes nearest to mining areas than those further away (geomean apportioned ore Pb = 88% (<1 km); 76% (1–2 km); 66% (>2 km)), reflecting spatial shifts in the balance of sources contributing to indoor contamination. Incorporation of house dust Pb reduced overestimation of IEUBK modelled blood Pb concentrations compared to when only soil Pb was used. These findings demonstrate that even in contexts where the source and environmental burden of metals are relatively apparent, geochemical relationships and exposures between outdoor and indoor environments are not always predictable, nor easily disaggregated.

Phytoremediation Potential of Four Native Plants in Soils Contaminated with Lead in a Mining Area

Metal pollution in soils is an issue of global concern, and lead (Pb) pollution is considered to be the most serious type. The arid and semi-arid areas of Northwest China are rich in Pb ore resources. In this study, four native crops [wormwood (Artemisia capillaris), dandelion (Taraxacum mongolicum), alfalfa (Medicago sativa), and plantain (Plantago asiatica L.)] that grow naturally around tailings slag in a mining area in Northwest China were selected to screen their ecological restoration impacts on Pb-contaminated soil. In pot experiments, four different metal lead pollution gradients (0, 2, 3, and 5‰ w/w) were set, and crop growth indexes such as plant height, root length, and biomass, together with the changes of soil Pb content in different tissues and organs before and after planting were analyzed. The results showed the difference in the amount of accumulated Pb in relation to the level of Pb content in the soil. It was found that wormwood and plantain have great potential as remediation plants for soil metal lead pollution in the arid and semi-arid lead bearing mining areas of Northwest China.

Trace element and Pb and Sr isotope investigation of tooth enamel from archaeological remains at El-Kurru, Sudan: Evaluating the role of groundwater-related diagenetic alteration

This study reports new trace element and Pb and Sr isotope compositions of tooth enamel from archaeological remains at a Medieval (Christian) cemetery located adjacent to the Kushite royal cemetery of El-Kurru, Sudan. The archaeological site of El-Kurru is located along the Nile River on the southern edge of the Nubian Plateau; the bedrock geology consists of Neoproterozoic crystalline basement and is overlain by fluvial sandstones and mudstones of Cretaceous age. El-Kurru is situated between two well-developed drainage basins, and in the past has been subjected to periodic (wadi-related) flooding as a result of intense local precipitation events. Enamel samples were taken from 18 individuals of varying ages and both sexes. Trace element abundances for a significant number of samples record elevated concentrations relative to modern (“in-vivo”) enamel, including Pb and U; however, the abundances for both elements do not correlate significantly with the contents of the remaining trace elements (Ba, Fe, Mg, Mn, Nd, Sr) investigated here. The calculated enrichment factors for all trace elements studied here relative to average crustal values are not consistent with exposure to Pb ores for human purposes, which is corroborated by the Pb isotope results. The Sr isotope compositions define 2 main groups that yield 87Sr/86Sr ratios that are either higher or lower than 0.7072 with similar Sr abundances (range between ~100 and ~400 ppm). The Pb isotope compositions are extremely variable and correlate well with their corresponding U/Pb ratios; the former overlap Pb isotope ratios for proximal Neoproterozoic rocks belonging to the Saharan Metacraton and Arabian Nubian Shield tectonic provinces. The combined trace element abundances and Sr and Pb isotope compositions for the enamel samples located within the Christian cemetery at El-Kurru are best interpreted to record interaction with groundwater that occurred post-mortem during flooding events. As reported in previous anthropological studies of a similar nature, the Pb isotope results reported here are particularly sensitive to monitoring post mortem diagenetic alteration given their extremely low abundances in non-altered tooth enamel. In contrast, the 87Sr/86Sr ratios have been minimally perturbed by post mortem alteration, and therefore most likely represent individuals with distinct Sr isotopic signatures inherited from different geographic regions.

Bać się czy się nie bać? Bioakumulacja, bioindykacja i toksyczność metali ciężkich Rośliny w świetle badań terenowych i laboratoryjnych

Heavy metals that pose a threat to the environment include lead (Pb), zinc (Zn), copper (Cu), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni) and mercury (Hg). Biomonitoring of environmental quality using plants is widely accepted as a reliable and inexpensive way of obtaining information on contamination also by heavy metals. It allows the assessment of the direction of changes in the natural environment and development of prognoses and methods for early warning related to predicted transformations in ecosystems. This paper presents the results of field and laboratory studies on floristic biodiversity in the areas of southern Poland related to extraction and processing of Zn and Pb ores. The paper also shows the selected plant defence mechanisms against the excess of heavy metals and the results of bioindication studies using different plant species, including the selected metallophytes related to the assessment of contamination levels and the most frequently used plant ecophysiological parameters. It is necessary to monitor contamination level, popularize knowledge and take action at the level of local authorities to mitigate adverse effects of human activity, bearing in mind possible bioaccumulation of heavy metals in the food chain and the adverse health effects associated with environmental contamination.

Radiogenic Pb Enrichment of Mississippi Valley-Type Metallic Ore Deposits, Southern Ozarks: Constraints Based on Geochemical Studies of Source Rocks and Their Diagenetic History

Southern Ozark Mississippi Valley-type ores are enriched in radiogenic Pb, with isotopic signatures suggesting that metals were supplied by two end-member components. While the less radiogenic component appears to be derived from various shale and sandstone units, the source of the more radiogenic component has not yet been identified. Analyses of cherts from the Early Ordovician Cotter Dolomite and tripolitic chert from the Early Mississippian Boone Formation contain highly radiogenic Pb, with isotopic ratios comparable to those of ores. However, most samples have lower 208Pb/204Pb and 207Pb/204Pb for a given 206Pb/204Pb compared to ores. These relationships demonstrate that the enriched Pb isotopic values of the ore array cannot be related to the host and regional lithologies sampled, suggesting that the source of high ratios may lay further afield. The slope of the linear trend defined by the Pb isotope ratios of ores corresponds to an age of about 1.19 Ga. Therefore, an alternative for the linear array is the involvement of Precambrian basement in supplying ore Pb. Rare earth element patterns show that diagenetic processes involving the action of groundwater and hydrothermal fluids affected the sampled lithologies to various degrees, with Cotter Dolomite having experienced the highest degree of alteration.

Cadmium and lead distribution in pyrite ores

The pyrite ores are strategic industrial resources which generally serve as raw material for producing sulfuric acid. However, during the mining and industrial processing activities, associated toxic elements of cadmium (Cd) and lead (Pb) could be released into the surroundings, posing a significant threat to local environment and human health. In this study, the Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme was used to investigate the geochemical fractionation of Cd and Pb in pyrite ores from a mining area located in Yunfu, western Guangdong, China. The results showed that most of Cd and Pb (&amp;gt;90%) were predominantly found in the geochemically mobile fractions, indicating that Cd and Pb were readily bioaccessible thus easily assimilated and accumulated by organisms. FESEM-EDS results showed that the studied pyrite ores were mainly composed of O, S, and Fe, while the XRD characterizations suggested that FeS2 and SiO2 were the major minerals. The high-resolution transmission electron microscope and element mapping characterization further confirmed that FeS2 was the main mineral of pyrite ores which contained relatively enriched toxic heavy metals (e.g., Pb and Cd). The findings highlight that an extremely large amount of geochemically mobile heavy metals can be released into the environmental media during the mining and utilization processes of pyrite ores based on IRMM sequential extraction protocol. Therefore, proper countermeasures against environmental risks of utilizing pyrite ores should be taken to mitigate the impacts on local ecosystem and human health.

Sampling and combined Pb and Ag isotopic analysis of ancient silver coins and ores

The combination of Pb and Ag isotopes in silver coins, artefacts, and ores greatly helps identifying ancient metal sources and detecting alteration such as lead addition, ore mixing, and metal recycling. The present study proposes a new set of procedures suitable for high-precision analysis of lead and silver isotopes in Ag-bearing ores and ancient silver coins. The protocols for combined Pb and Ag extraction and purification are based on multi-step ion-exchange and reversed-phase partition chromatography. In addition to conventional drilling, which irreversibly damages the silver object being sampled, a new method was developed to collect metal from silver coins by etching their edges with a solution of hydrogen peroxide and ammonia (H2O2 + NH4OH), either pure or with added dispersed silicon carbide (SiC) to increase etching efficiency, a technique that only damages the coin patina. This technique can also be applied to silver artefacts other than coins with minor modifications to adapt to different object shapes. Multi-collection inductively-coupled plasma mass spectrometry (MC-ICP-MS) was used to measure the isotopic compositions of both Pb and Ag in ores and coins. Variations in Pb and Ag isotopic compositions are uncorrelated for all the material analyzed, whether ores or silver coins, which demonstrate that isotope variability results from physically different processes. Evidence of mixing between different components is observed for ores, while etched and drilled coins show a conspicuous range of Pb and Ag isotopic compositions. The latter is interpreted as resulting from mass-dependent fractionation during surficial alteration under oxidizing burial conditions, and from patina formation. Silver in patina is isotopically light due to the formation of Ag2S, while the layer below the patina is isotopically heavy. Preliminary patina removal followed by H2O2 + NH4OH etching with suspended SiC may be used as an alternative to coin drilling when the latter is not possible such as for rare and precious coins. The present techniques will further help distinguish primary Pb isotopic variability in artefacts and coins from secondary variations due to underground interaction with the water table, weathering from prolonged burial, and curatorial handling.

Honey Maps the Pb Fallout from the 2019 Fire at Notre-Dame Cathedral, Paris: A Geochemical Perspective

The fire at Notre-Dame cathedral, Paris, in April 2019, was an acute pollution event, releasing lead (Pb)-rich dust into the city. To assess Pb distribution, honey samples (n = 36) were collected (in July 2019) from hives throughout the Ile-de-France following the fire and were analyzed for a suite of metal concentrations and Pb isotopic compositions. Honey from hives downwind of the fire has elevated Pb concentrations (0.023 μg/g Pb, geometric mean) compared to other honey from central Paris (0.008 μg/g), prefire Paris (0.009 μg/ g), and the Rhone-Alpes region (0.004 μg/g). The Pb isotopic range for all analyzed honey (Paris and Rhone-Alpes, 1.144−1.179 206 Pb/ 207 Pb, 2.079−2.125 208 Pb/ 206 Pb) falls within the modern Pb isotopic range for French aerosols and sediments, signifying that the fire did not perturb the isotopic composition of Parisian honey. The variations in downwind Pb concentrations demonstrate the utility of honey as a biomonitor after an acute pollution event. The isotope results are supported by the construction history of Notre-Dame cathedral and historical record of Pb ores used throughout France.

Investigations of Pb and Cu Isotopes to Trace Contamination Sources from the Artificial Shihwa Lake in Korea

Jeong, H.; Choi, J.Y.; Lee, J., and Ra, K., 2020. Investigations of Pb and Cu isotopes to trace contamination sources from the artificial Shihwa Lake in Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1122-1127. Coconut Creek (Florida), ISSN 0749-0208.The concentrations of heavy metals and Pb and Cu isotopes in sediments from five streams (A–G) around the Shihwa National Industrial Complex in Korea were investigated with the aim of identifying sources of metal pollution. The average concentration of Zn (21,106 mg/kg) was the highest, followed by Cu (2,804 mg/kg), Ni (2,126 mg/kg), Pb (897 mg/kg), Cr (807 mg/kg), As (18 mg/kg), Cd (8.0 mg/kg), and Hg (1.4 mg/kg). The concentrations tended to be highest in sediments from stream G. The 206Pb/207Pb and 208Pb/206Pb ratios of stream sediments ranged from 1.1302 to 1.1626 and 2.0983 to 2.1990, respectively. The Pb isotopes in stream sediments showed linear trends both Chinese Pb ore and Korean Pb–Zn Ore deposit. The Pb isotopic composition overlapped with Shihwa road dust values. The δ65CuAE647 values of stream sediments ranged from –0.16‰ to 0.64‰, clustering in two groups, one relatively enriched in the light Cu isotope (0.08‰–0.13‰) and another enriched in the heavy Cu isotope (0.37‰–0.48‰). Our results indicate that streams F and G are relatively enriched in heavy Cu isotopes. 208Pb/206Pb vs. δ65CuAE647 plots indicate that the two branches of the Shingil stream (E and F) are noticeably distinguished, with their isotopic compositions suggesting different pollution sources. The Cu and Pb isotopic compositions reflect those of road dust, and suggest that the stream sediments were affected by road dust transported in stormwater runoff. Thus, road dust may be a potential source of metal pollution in the stream sediments of industrial regions in Korea.

Total-reflection X-ray fluorescence spectrometry as a tool for the direct elemental analysis of ores: Application to iron, manganese, ferromanganese, nickel-copper sulfide ores and ferromanganese nodules

This paper presents a simple and fast method for the determination of major and minor elements in iron, manganese, ferromanganese, nickel‑copper sulfide ores and oceanic ferromanganese nodules by total-reflection X-ray fluorescence spectrometry (TXRF). The preparation of suspension from 5 mL of 1% Triton solution and 20 mg of fine powder with a median particle size of less than 10 μm was used as a sample preparation strategy for direct TXRF analysis. Quantification of elements was performed by the internal standard method. Critical sample mass when the sample could be considered ‘thin’ was calculated for various matrices using Ga as an internal standard. The influence of sampling, particle size, and the internal standard distribution on the reproducibility of the analysis was evaluated. For ore powders with low wettability, preliminarily drying the powder mixed with Ga solution is recommended to increase the uniformity of the distribution of the internal standard. Accuracy was evaluated for S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, and Pb in ores and nodules and for V, Co, Ni, Sr, Y and As in nodules. TXRF provides fast determination of some major and minor elements in ores and nodules; however, the determination of low levels of elements in the ore matrix can only be considered semi-quantitative.

Lead distribution in urban street dust and the relationship with mining, gross domestic product GDP and transportation and health risk assessment

Lead (Pb) is an important pollutant and it is of significance to explore the Pb distribution, influencing factors and health risk. Pb concentration and mass load per unit area in 385 street dust samples collected from 19 cities in China were determined during 2011-2013. The results show that the Pb concentration are 68.8, 105.4, 41.7, 49.7, 75.6, 81.7, 131.9, 67.5, 109.3, 164.1, 74.8, 66.4, 99.8, 58.4, 114.0, 59.6, 103.7, 55.4 and 80.4 for Beijing, Chengdu, Daqing, Harbin, Jilin, Jinan, Kunming, Lanzhou, Luoyang, Panzhihua, Qingdao, Yinchuan, Guangzhou, Tangshan, Xi’an, Guangyuan, Nanjing, Taiyuan and Tianjin, respectively. The Pb pollution level of urban street dust varies among cities in the range of 1.72–5.56 times higher than soil background values. The allometric function can fit the change in Pb concentration with particle size well. The medium-sized (38–120 μm) particles contributed 60.2%–80.4% to the Pb load and should be highlighted when selecting street dust management techniques. Influenced by the distribution of Pb ore, the Pb concentration of urban street dust in China shows obvious regional differences, with value in the south 112% higher than that in the north. Among all kinds of mining types, metal-related mining activities discharge a large amount of Pb dust in the process of crushing and smelting, thus contributing most to the Pb load. The Pb load was also affected by transportation. The relationship between Pb load and gross domestic product (GDP) was described with the environmental Kuznets curve (EKC) model, which indicated that the Pb emissions of most cities were still increasing. Finally, the human health risk assessment model with adjusted parameters showed that the Pb risk of all cities was below the threshold. Despite all this, given the EKC law of Pb emission, long-term follow-up assessments are needed.

Stable isotope and fluid inclusion studies of early Zn-Cu-(Ni-Co)-rich ores, lower ore zone of Brushy Creek mine, Viburnum Trend MVT district, Missouri, U.S.A.: Products of multiple sulfur sources and metal-specific fluids

Mississippi Valley-type (MVT) deposits of the Viburnum Trend are typically lead-dominant and occur in the upper portion of the Cambrian Bonneterre Dolomite. Unusual zinc- and copper-rich ores, with notable enrichments in Ni, Co, and Ag, have been discovered within the lower Bonneterre Dolomite, >30 m below the district’s main ore-bearing horizon. These ores appear to be localized along fault/fracture zones within the Lamotte Sandstone, which promoted extreme dissolution of the base of the overlying Bonneterre Dolomite and resulted in pronounced vertical zoning of early Ni-Co, Cu, Zn and Pb ores above the sandstone/dolomite contact.Stable isotope and fluid inclusion studies were undertaken to assess whether the deep ores resulted from a single fluid reservoir that evolved from Cu-Ni-Co-rich to Zn-rich to Pb-rich or are instead products of distinct fluids unrelated to the stratigraphically higher, main Pb-rich ores of the district. Sphalerite-hosted fluid inclusions from the lower orebody appear to be geochemically distinct from those that formed the upper orebodies. They record the highest K/Na and Mg/Na ratios in the southeast Missouri MVT district, suggesting dominance of siliceous lithologies (arkose and/or felsic igneous rocks) over limestones along their ore-fluid pathways. Paragenetic trends indicate that distinct fluid compositions are associated with specific generations of sphalerite, which likely reflects the presence of multiple fluids.The δ34S values of ore minerals (early pyrite and chalcopyrite, −7 to +5‰; early sphalerite, +6 to +15‰; main sphalerite, +7 to +17‰ V-CDT) indicate deposition from fluids that utilized isotopically distinct sulfide reservoirs. Low-δ34S sulfur sources for early ores likely included sulfide in local brines within the Lamotte Sandstone and diagenetic sulfide minerals within the basal units of the Bonneterre Dolomite. A trend of increasing δ34S values of ore sulfides (from −5 toward +17‰) with vertical distance above the Lamotte Sandstone-Bonneterre Dolomite contact indicates that as the deep ore fluid system worked its way upward, it breached less permeable units in the lower Bonneterre Dolomite, allowing incorporation of high-δ34S sulfide from brines present higher in the stratigraphic section. A concomitant up-section pattern of decreasing δ18O values of dolomite cement and recrystallized remnant host rock (from −3 toward −9‰ V-PDB) is also consistent with a localized, deep mineralizing fluid system, which interacted progressively with the stratigraphically higher, regional-scale, Pb-rich fluid system.The episodic nature of metal sulfide deposition in the lower ore zone points to a system in which fluid mixing would have been highly variable, both temporally and spatially. Reaction path models require mixing of multiple, ore metal-specific and sulfide-bearing fluids in order to form the orebody. The sequence and concentrations of metal sulfides are inconsistent with ore formation from a single, evolving metal-bearing fluid.This study indicates that faults localized early metal- and sulfide-bearing fluids, facilitating mixing of fluids that resulted in the accumulation of high-grade ores near the Bonneterre Dolomite-Lamotte Sandstone contact. Recognition of fault/fracture patterns beneath more typical Pb-rich orebodies in the Viburnum Trend may be a viable exploration strategy for similar Zn-Cu-Co-Ni-rich deposits.

Petrogenesis and Tectonic Setting of Ore-Associated Intrusive Rocks in the Baiyinnuoer Zn–Pb Deposit, Southern Great Xing’an Range (NE China): Constraints from Zircon U–Pb Dating, Geochemistry, and Sr–Nd–Pb Isotopes

The Baiyinnuoer skarn Zn–Pb deposit, located in the Southern Great Xing’an Range, Northeast China, is the largest Zn–Pb deposit of the northern China, with a total reserve of 32.74 Mt at average grades of 5.44% Zn and 2.02% Pb. The Zn–Pb ore bodies are hosted in the Lower Permian Huanggangliang Formation. The results of zircon U–Pb geochronology show that the ore-associated granodiorite porphyry, granodiorite, and diorite were emplaced at 248 ± 1.3, 251 ± 1.8, and 249 ± 1.4 Ma, respectively. The granodiorites and granodiorite porphyry have low P2O5 (0.13–0.23 wt %) and A/CNK (0.79–1.05) values, and their SiO2 and P2O5 contents are negatively correlated, indicating I-type affinity. The positive εNd(t) values (+1.3 to +1.8) and young two-stage model ages (TDM2) (880–916 Ma) of the Baiyinnuoer intrusive rocks suggest that they might have formed by the mixing of both mantle and crustal materials. The variations in the major elements, Rb, Sr, and Ba, and the negative Nb–Ta–Ti anomalies indicate that fractional crystallization might have occurred during magma ascent. In combination with the regional geology, the new geochronological, geochemical, and isotopic data reveal that the ore-associated intrusive rocks at Baiyinnuoer were formed in a post-collision setting in the Late Permian.

A 10,000-year record of trace metal and metalloid (Cu, Hg, Sb, Pb) deposition in a western Alpine lake (Lake Robert, France): Deciphering local and regional mining contamination

Concentrations of trace metals and metalloids (Cu, Hg, Sb, Pb), major elements, stable Pb and C isotope ratios, total organic carbon (TOC), C/N atomic ratios, were analyzed in two sediment cores encompassing 10,000 years of sedimentation sampled in Lake Robert (French Alps).The results showed that the establishment of a soil cover and vegetation during the Holocene climatic optimum increased Cu and Hg deposition in sediments. Results also enabled reconstruction of the history and local vs regional origins of pollution. During the Bronze Age (1800–1000 BC), Cu mining activities increased Hg and Sb accumulation rates (AR) by a factor of 7 (Hg) and 9 (Sb) compared to pre-Bronze Age values. The rise in Hg AR was equivalent to that of the industrial era highlighting a major local Hg point source not recorded in regional archives. During the Iron Age, Pb pollution was attributed to Sicilian ores whereas during the Roman Empire Pb pollution had the isotopic signature of Spanish Pb ores. During the Medieval period (ca. AD 1200), Pb and Hg pollution was due to the exploitation of the local Ag–Pb mines. Finally, during the industrial era, metal accumulations rates were 90 (Pb), 5 (Hg) and 20 (Sb) times higher than those in the pre-Bronze Age. The isotopic composition of Pb reflected mixed sources including industrial Pb and gasoline Pb. Synchronously, the increase in Sb and Hg pollution is attributed to global and regional atmospheric pollution.

Exploring Spatially Non-stationary Relationships in the Determinants of Mineralization in 3D Geological Space

Exploring the spatial relationships between various geological features and mineralization is not only conducive to understanding the genesis of ore deposits but can also help to guide mineral exploration by providing predictive mineral maps. However, most current methods assume spatially constant determinants of mineralization and therefore have limited applicability to detecting possible spatially non-stationary relationships between the geological features and the mineralization. In this paper, the spatial variation between the distribution of mineralization and its determining factors is described for a case study in the Dingjiashan Pb–Zn deposit, China. A local regression modeling technique, geological weighted regression (GWR), was leveraged to study the spatial non-stationarity in the 3D geological space. First, ordinary least-squares (OLS) regression was applied, the redundancy and significance of the controlling factors were tested, and the spatial dependency in Zn and Pb ore grade measurements was confirmed. Second, GWR models with different kernel functions in 3D space were applied, and their results were compared to the OLS model. The results show a superior performance of GWR compared with OLS and a significant spatial non-stationarity in the determinants of ore grade. Third, a non-stationarity test was performed. The stationarity index and the Monte Carlo stationarity test demonstrate the non-stationarity of all the variables throughout the area. Finally, the influences of the degree of non-stationary of all controlling factors on mineralization are discussed. The existence of significant non-stationarity of mineral ore determinants in 3D space opens up an exciting avenue for research into the prediction of underground ore bodies.

Application of electromagnetic transient method for Zn\u2013Pb exploration at the Cho Dien\u2013Cho Don District, Bac Can Province, North Vietnam

Effectiveness of transient electromagnetic method (TEM) used for the localization of Pb–Zn ore bodies at the Cho Don deposit, province Bac Can, North Vietnam is appraised based on the modelling processes results. Conductive Pb–Zn ore bodies hosted in high-resistive limestone are in good conditions for the application of the TEM. The modelling process relays on the calculation of the voltage decay in time domain formed from the induced magnetic field diffusing into the study medium, when a pulse current with a given frequency is flowing in a transmitting loop coil. The model results show that the power current of 1 A transmitted from the coils with 100 or 400 m of size is effective for localization of the Zn–Pb ore bodies. However, the resolution and penetration depth of the TEM with a coil of L = 100 m is better and shorter in comparison with those in the case using the coil L = 400 m.

Stable isotopes of nonsulphide Zn–Pb ores in Britain and Ireland: fluid characteristics and palaeoclimatic variability

Stable isotope (C–O) analysis was applied to smithsonites and cerussites from Zn(Pb) nonsulphide ores from Britain and Ireland, to determine the nature of the fluids responsible for the precipitation of secondary carbonates, and any relationship with palaeoclimatic conditions. The carbon isotope compositions of the Irish smithsonites show a major contribution of organic carbon whereas those of both Zn- and Pb-carbonates in the UK deposits indicate contribution of organic carbon and host-rock carbonates. δ 18 O VSMOW values for cerussite from both areas are about 13‰ lower than those of smithsonites, UK smithsonite δ 18 O VSMOW values are more variable than those for cerussites and the Irish smithsonites have unusually high values. Isoscape maps indicate that δ 18 O values for both carbonates are higher in the west and decrease toward the east. This trend correlates with a general decrease in the oxygen isotope compositions of rainwater moving eastward, and suggests that oxidation of sulphides occurred at temperatures of about 15–20°C, under climatic conditions warmer than today. Supplementary material: A comprehensive overview of the investigated sites, detailed data for the samples and SEM images are available at https://doi.org/10.6084/m9.figshare.c.4579535

The mixing of multi-source fluids in the Wusihe Zn–Pb ore deposit in Sichuan Province, Southwestern China

The Sichuan–Yunnan–Guizhou (SYG) metallogenic province of southwest China is one of the most important Zn–Pb ore zones in China, with ~ 200 Mt Zn–Pb ores at mean grades of 10 wt.% Zn and 5 wt.% Pb. The source and mechanism of the regional Zn–Pb mineralization remain controversial despite many investigations that have been conducted. The Wusihe Zn–Pb deposit is a representative large-scale Zn–Pb deposit in the northern SYG, which mainly occurs in the Dengying Formation and yields Zn–Pb resources of ~ 3.7 Mt. In this paper, Zn and S isotopes, and Fe and Cd contents of sphalerite from the Wusihe deposit were investigated in an attempt to constrain the controls on Zn and S isotopic variations, the potential sources of ore-forming components, and the possible mineralization mechanisms. Both the δ66Zn and δ34S values in sphalerite from the Wusihe deposit increase systematically from the bottom to the top of the strata-bound orebodies. Such spatial evolution in δ66Zn and δ34S values of sphalerite can be attributed to isotopic Rayleigh fractionation during sphalerite precipitation with temperature variations. The strong correlations between the Zn–S isotopic compositions and Fe–Cd concentrations in sphalerite suggest that their variations were dominated by a similar mechanism. However, the Rayleigh fractionation mechanism cannot explain the spatial variations of Fe and Cd concentrations of sphalerite in this deposit. It is noted that the bottom and top sphalerites from the strata-bound orebodies document contrasting Zn and S isotopic compositions which correspond to the Zn and S isotopic characteristics of basement rocks and host rocks, respectively. Therefore, the mixing of two-source fluids with distinct Zn–S isotopic signatures was responsible for the spatial variations of Zn–S isotopic compositions of sphalerite from the Wusihe deposit. The fluids from basement rocks are characterized by relatively lighter Zn (~ 0.2 ‰) and S (~ 5 ‰) isotopic compositions while the fluids from host rocks are marked by relatively heavier Zn (~ 0.6 ‰) and S (~ 15 ‰) isotopic compositions.