Minerals Zn Research Articles

Constraints of C[sbnd]H[sbnd]O[sbnd]S[sbnd]Pb isotopes and fluid inclusions on the origin of the giant Zhugongtang carbonate-hosted Pb–Zn deposit in South China

The Sichuan–Yunnan–Guizhou (SYG) metallogenic province on the western margin of the Yangtze Block has long been a research focus and is an important region of Pb–Zn mineralization in China, but its genesis is poorly constrained. This study examines the Zhugongtang carbonate-hosted Pb–Zn deposit (>3.0 Mt, 0.09–35.04 wt% Pb + Zn), the largest discovery made in the past decade in the southeastern part of the SYG metallogenic province. Fluid inclusions from sphalerite and calcite, CHO–isotopes from calcite, and S–Pb isotopes from sulfide minerals in the Zhugongtang Pb–Zn deposit were analyzed to understand the sources and genesis of the metals and hydrothermal fluids. Fluid inclusions in sphalerite and calcite from the largest ore body indicate that the fluids of the main mineralization stage had low temperatures (105 °C–210 °C) and moderate salinities (0.35–12.89 wt% NaCl equiv.). The sulfides are characterized by narrow ranges of sulfur isotope compositions (δ34Spyrite = +14.27 ‰ to +15.89 ‰, δ34Ssphalerite = +14.31 ‰ to +15.53 ‰, and δ34Sgalena = +10.64 ‰ to +12.97 ‰), indicating that reduced sulfur was derived from sedimentary sulfate in the Devonian to Permian carbonate host rocks by thermochemical sulfate reduction with the addition of organic matter. The δ13CPDB and δ18OSMOW values of calcite range from − 8.6 ‰ to +0.82 ‰ and +15.45 ‰ to +19.41 ‰, respectively, which are similar to values for mantle, marine carbonate rocks, and sedimentary organic matter. The negative correlation between δ13CPDB and δ18OSMOW values indicates that CO2 in the hydrothermal fluids was sourced from marine carbonate rocks and sedimentary organic matter. Calculated δ18OH2O and δDH2O values range from +3.5 ‰ to +7.5 ‰, and −93 ‰ to −52 ‰, respectively, indicating that the ore-forming fluids were dominantly metamorphic, but diluted by meteoric water that had reacted with organic matter. The galena samples yield 206Pb/204Pb values of 18.52 to 18.82, 207Pb/204Pb of 15.68 to 15.93, and 208Pb/204Pb values of 38.97 to 39.96. The μ and ω values of the sulfides range from 9.61 to 10.07 and 38.84 to 43.67, respectively. These data plot on the upper crust Pb evolution curve, generally in the field of Devonian to lower Permian sedimentary rocks, although the value for one sample falls in the field of Proterozoic metamorphic rocks, pointing to a complex origin for the ore-forming materials. Overall, the fluid inclusion and isotope data, together with geological evidence, suggest that the ore-forming fluids of the Pb–Zn deposit were sourced from deep metamorphic water with the features of low temperatures and moderate salinities, and the ore-forming metals were sourced from Devonian to lower Permian sedimentary rocks and partly from basement rocks. The genesis of the Zhugongtang ore is typical of SYG-type deposits.

The occurrence of cobalt and implications for genesis of the Pusangguo cobalt-rich skarn deposit in Gangdese, Tibet

The Pusangguo cobalt-rich skarn deposit occurs in Gangdese, Tibet. In recent years, research on this deposit has detailed the geochronology, petrogenesis, fluid inclusions and skarn mineralogy, but there has been a lack of focus on the occurrence of cobalt. We present X-ray fluorescence, scanning electron microscopy and electron probe microanalyses that address this omission and help elucidate the genesis of cobalt-rich skarn deposits. Correlations between Co and other ore-forming elements (Cu, Pb, Zn and Ag) reveal that Co mineralization was synchronous with other metals. Photomicrographs and backscattered electron and X-ray maps of thin sections, confirm that cobalt mineralization is usually associated with chalcopyrite, sphalerite and other sulfides, which developed at the retrograde skarn stage with quartz, carbonate minerals, tremolite and other skarn-related minor phases. Three independent cobalt minerals are identified (cobaltite, carrollite, and linnaeite). The EPMA results further reveal two different occurrences of cobalt (independent cobalt minerals and isomorphous substitution Co in sulfides) in the Pusangguo deposit. Compared with chalcopyrite (mean Co content = 0.06 ± 0.06 wt.%, 1σ, n = 142) and galena (mean Co content = 0.02 ± 0.04 wt.%, 1σ, n = 82), both pyrite and sphalerite typically contain obviously higher Co contents (mean = 0.16 ± 0.17 wt.%, 1σ, n = 97 and 0.20 ± 0.10 wt.%, 1σ, n = 108, respectively). The correlations between Co and other elements indicate that Co + Ni replace Fe in pyrite via isomorphous substitution while Co + Fe replace Zn in sphalerite. These results further indicate that Co and Zn mineralization occurred at the same time. Combined with previously published Sr-Nd isotopic data on skarn minerals, the mineralization of Cu, Pb, Zn, Ag and Co were likely derived from, or share a common source with the intrusions at Pusangguo.

Leaching of heavy metal(loid)s from historical Pb–Zn mining tailing in abandoned tailing deposit: Up-flow column and batch tests

This study aims to investigate the water-leaching characteristics of heavy metal(loid)s (HMs) from historical Pb–Zn mine tailing of an abandoned tailing deposit in eastern China. Up-flow column and batch leaching tests were conducted at different liquid-to-solid (L/S) ratios to estimate the releases of HMs and investigate the controlling mechanisms. Calcite and silicate were the dominant minerals in the tailing and the HMs contents followed the order of Zn (2371 mg/kg) > Pb (2061 mg/kg) > Cu (109 mg/kg) > Cr (47.8 mg/kg) > As (15.9 mg/kg) > Cd (5.1 mg/kg). Moreover, considerable fractions of Pb, Zn, and Cd existed in the acid-soluble forms (41–47%). Column and batch leaching tests consistently showed that limited quantities (<0.002%) of HMs could be leached from this historical tailing. In particular, variations in column conditions (e.g., length, flow rate, and initial saturation) significantly affected the release fluxes from the columns but had a relatively limited effect on the leaching mechanisms. The estimated results of HM release suggested that the leaching process was predominantly solubility-controlled and the dissolution of Ca-bearing minerals (e.g., calcite) primarily controlled the release of HMs. The studied tailing had a limited impact on the quality of the surrounding aquatic environments because the water-leaching concentrations of HMs were generally lower than the Chinese standards for drinking water. Only for Pb, the leaching results in column tests were significantly lower than those in batch tests; whereas the results in column tests for other HMs were comparable to those in batch tests to a certain extent. Based on the column test results, the amounts of HMs potentially released from the abandoned tailing deposit (height, 10 m; footprint area, 30,000 m2; tailing dry density, 1.9 × 103 kg/m3) followed a decreasing order of Zn (4.2 × 105 kg) > Cu (2.3 × 104 kg) > Pb (1.4 × 104 kg) > Cr (2.3 × 104 kg) > Cd (1.6 × 103 kg) > As (1.2 × 103 kg) over the 75-year assessment period (corresponding to an L/S ratio of 10 L/kg with an annual precipitation of 1500 mm).

Carbonate mineral controls the transport of Cd from tailings to surrounding soils: An example from Cd-rich Niujiaotang Zn mine in Guizhou Province, Southwest China

Heavy metal pollution derived from the oxidation of sulfides in Pb-Zn mine tailings has been a common public concern. Although the oxidative dissolution of sphalerite will release cadmium into the soil environment, it is still unclear whether other minerals contain a large amount of cadmium and how much these minerals contribute to the surrounding environmental media. In this paper, XRD, particle size analyzer, SEM-EDS and improved BCR sequential extraction method were used to analyze cadmium rich zinc mine tailing and adjacent farmland soil in Duyun, Guizhou Province. The results show that the average contents of Pb, Zn, and Cd in tailing are 214 ± 71 mg/kg, 2668 ± 773 mg/kg, and 37.5 ± 9.97 mg/kg respectively. While in the surrounding soil, they were 519 ± 280 mg/kg, 3,779 ± 2614 mg/kg, and 30.8 ± 14.4 mg/kg respectively. The mineralogical composition of tailing is mainly dolomite and less pyrite. Cadmium in tailing is mainly in weak acid extractable state, indicating that cadmium mainly exists in dolomite of tailing. Pyrite in tailing generates acid through oxidation, which accelerates the dissolution of dolomite, thus releasing Cd from minerals and migrating to surrounding farmland, resulting in soil cadmium pollution. This study reveals an important process that has been neglected. Carbonate minerals play an important role in the migration of cadmium in the tailing of the Mississippi Valley-type (MVT) lead-zinc mine and the soils affected by the tailing.

Interpretation of hydrothermal alteration and structural framework of the Huize Pb–Zn deposit, SW China, using Sentinel-2, ASTER, and Gaofen-5 satellite data: Implications for Pb–Zn exploration

The Huize Pb–Zn deposit is one of the largest and high–grade Pb–Zn deposits in the world, containing more than 7 Mt Pb and Zn reserves at an ore grade of ∼30–35 % Pb + Zn. Therefore, brownfield exploration of additional Pb and Zn orebodies at Huize Pb–Zn deposit is of high priority. Hydrothermal alteration minerals and structural features are typically associated with Pb–Zn mineralization, which can be identified quickly and economically using a multi-source remote sensing satellite dataset. In this study, Sentinel-2, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and Gaofen-5 (GF-5) satellite remote sensing imagery were employed for brownfield exploration of additional Pb–Zn orebodies in the Huize Pb–Zn deposit. The Sentinel-2 satellite remote sensing imagery was used to interpret the structure and map oxides/hydroxides by implementing the band ratio (BR) and principal components analysis (PCA) method; the ASTER satellite data were applied to map argillic, quartz, and carbonate hydrothermal alteration minerals using the PCA method; the GF-5 satellite data were utilized to map hematite, kaolinite, calcite, and dolomite minerals by the mixture tuned matched filtering (MTMF) method; and the mapped hydrothermal alteration information was verified by field reconnaissance and laboratory analysis. Finally, remote sensing geological exploration characteristics of the Huize Pb–Zn deposit were summarized by comprehensively analyzing the hydrothermal alteration minerals and structural characteristics, and three new brownfield exploration target zones of Pb–Zn mineralization were delineated. The study can provide a reference for the brownfields exploration in the vicinity of an existing Pb–Zn deposit around the world.

Alleviation of heavy metal stress and enhanced plant complex functional restoration in abandoned Pb–Zn mining areas by the nurse plant Coriaria nepalensis

Heavy metal pollution caused by mining has been a topic of concern globally because it threatens ecological functions and human health. Nearly all current remediation strategies take into account only such short-term issues as how to reduce or stabilize the content of heavy metals in soil, how to reduce the toxicity of heavy metals, and how to preserve water, soil and nutrients. However, little attention is paid to such long-term issues as whether plants can survive, whether communities can be stabilized, and whether ecosystem functions can be restored. Therefore, improving plant diversity and community stability are key aspects of improved mine restoration. To explore the possibility of reconstructing plant complexes in mining areas, the local nurse plant Coriaria nepalensis was selected as the research object for a study in the Huize Pb–Zn mining area of southwest China. C. nepalensis could increase the contents of nutrient elements (C, N, and P), reduce the contents of heavy metals (Mn, Cu, Zn, Cd, and Pb), and strengthen the plant complex functions (diversity, functional traits, and complex biomass) in its root zone. In general, C. nepalensis can form fertility islands (survival islands) in mining areas, which facilitate the colonization and success of additional less stress-resistant species. We propose C. nepalensis as a key species for use in restoration based on its ability to restore ecosystem functions under extremely stressful conditions. We encourage combination of C. nepalensis with other nurse plants to reinforce the rehabilitation of ecosystem functions.

Potential mobilization of cadmium and zinc in soils spiked with smithsonite and sphalerite under different water management regimes

Particulate cadmium (Cd) and zinc (Zn) are ubiquitous in agricultural soils of Pb–Zn mining regions. Water management serves as an important agronomic measure altering the bioavailability of Zn and Cd in soils, but how this affects particulate Cd and Zn and the underlying mechanisms remain largely unknown. Microcosm soil incubation combined with spectroscopic and microscopic characterization was conducted. During a two-year-long incubation period we observed that the concentrations of soil CaCl2-extractable Zn and Cd increased 3–10 times in sphalerite-spiked soils and 1–2 times in smithsonite-spiked soils under periodic flooding conditions due to the long-term dissolution of sphalerite (SP) and smithsonite (SM). However, the increase in the concentration of CaCl2-extractable metals (Zn: from 0.607 mg kg−1 to 1.051 mg kg−1 and Cd: from 0.047 mg kg−1 to 0.119 mg kg−1) was found only in SP-treatment under continuous flooding conditions, indicating the mobilization of metals. Ultrafiltration analysis shows that the nanoparticulate fraction of Zn and Cd in soil pore water increased 5 and 7 times in SP-treatments under continuous flooding conditions, suggesting the increment of metal pools in soil pore water. HRTEM-EDX-SAED further reveals that these nanoparticles were mainly crystalline ZnS and Zn-bearing sulfate nanoparticles in the SP-treatment and amorphous ZnCO3 and ZnS nanoparticles in the SM-treatment. Therefore, the formation of the stable crystalline Zn-bearing nanoparticles in the SP-treatment may explain the elevation of the concentration of soil CaCl2-extractable Zn and Cd under continuous flooding. The potential mobility of particulate metals should therefore be expected in scenarios of continuous flooding such as paddy soils and wetland systems.

Legacy of contamination with metal(loid)s and their potential mobilization in soils at a carbonate-hosted lead-zinc mine area

Chemical weathering of carbonate-hosted Pb–Zn mines via acid-promoted or oxidative dissolution generates metal-bearing colloids at neutral mine drainage sites. However, the mobility and bioavailability of the colloids associated with metals in nearby soils are unknown. Here, we monitored the mobility of metal(loid)s in soils affected by aeolian deposition and river transport in the vicinity of a carbonate-hosted Pb–Zn mine. Using chemical extraction, ultrafiltration, and microscopic and spectroscopic analysis of metals we find that contamination levels of the soil metals cadmium (Cd), lead (Pb) and zinc (Zn) were negatively correlated with metal extractability. However, nano-scale characterization indicates that colloid-metal(loid) interactions induced potential mobilization and increased risk from metal(loid)s. Dynamic light scattering (DLS) and HRTEM-EDX-SAED analysis further indicate that organic matter (OM)-rich nano-colloids associated with calcium (Ca), silicon (Si) and iron (Fe) precipitates accounted for the majority of the dissolved metal fractions in carbonate-hosted Pb–Zn mine soils. More stable nano-crystals (ZnS, ZnCO3, Zn-bearing sulfates, hematite and Al–Si–Fe compounds) were present in the pore water of aeolian-impacted upland soils rather than in river water-impacted soils. Our results suggest that future work should consider the possibility that potential mobilization of metal(loid)s induced by the weathering and transformation of these metal-bearing nano-crystals to metal-bearing amorphous colloids, potentially elevating metal mobility and/or bioavailability in river water-impacted agricultural soils.

Maternal supplementation of different trace mineral sources on broiler breeder production and progeny growth and gut health.

Trace mineral minerals Zn, Cu, and Mn play important roles in breeder production and progeny performance. The objective of this study was to determine maternal supplementation of trace mineral minerals on breeder production and progeny growth and development. A total of 540 broiler breeders, Cobb 500 (Slow feathering; 0–66 weeks old) were assigned to one of three treatment groups with the same basal diet and three different supplemental trace minerals: ITM–inorganic trace minerals in sulfates: 100, 16, and 100 ppm of Zn, Cu, and Mn respectively; MMHAC -mineral methionine hydroxy analog chelate: 50, 8, and 50 ppm of bis-chelated MINTREX®Zn, Cu and Mn (Novus International, Inc.), and TMAAC - trace minerals amino acid complex: 50, 8, and 50 ppm of Zn, Cu, and Mn. At 28 weeks of age, eggs from breeder treatments were hatched for progeny trial, 10 pens with 6 males and 6 female birds per pen were fed a common diet with ITM for 45 days. Breeder production, egg quality, progeny growth performance, mRNA expression of gut health associated genes in breeder and progeny chicks were measured. Data were analyzed by one-way ANOVA; means were separated by Fisher’s protected LSD test. A p-Value ≤ 0.05 was considered statistically different and 0.1 was considered numerical trend. Breeders on ITM treatment had higher (p < 0.05) body weight (BW), weight gain and lower (p < 0.05) feed conversion ratio (FCR) from 0 to 10 weeks, when compared to birds fed MMHAC. MMHAC significantly improved egg mass by 3 g (p < 0.05) and FCR by 34 points (0.05 < p < 0.1) throughout the reproductive period (26–66 weeks) in comparison to ITM. MMHAC improved (p < 0.01) egg yolk color versus (vs.) ITM and TMAAC in all periods, except 28 weeks, increased (p < 0.01) eggshell thickness and resistance vs. TMAAC at 58 weeks, and reduced (p < 0.05) jejunal NF-κB gene expression vs. TMAAC at 24 weeks. There was a significant reduction in tibial dry matter weight, Seedor index and resistance for the breeders that received MMHAC and/or TMAAC when compared to ITM at 18 weeks. Lower seedor index but numerically wider tibial circumference was seen in hens fed MMHAC at 24 weeks, and wider tibial circumference but lower tibial resistance in hens fed TMAAC at 66 weeks. Maternal supplementation of MMHAC in breeder hens increased (p < 0.0001) BW vs. ITM and TMAAC at hatching, reduced (p < 0.05) feed intake vs. ITM at d14 and d28, and improved (p < 0.01) FCR and performance index vs. TMAAC at d28, reduced (p < 0.01) NF-κB gene expression and increased (p < 0.05) A20 gene expression vs. TMAAC on d0 and vs. ITM on d14, reduced (p < 0.05) TLR2 gene expression vs. ITM on d0 and vs. TMAAC on d14, increased (p < 0.05) MUC2 gene expression vs. both ITM and TMAAC on d45 in progeny jejunum. Overall, these results suggest that supplementation with lower levels of MHA-chelated trace minerals improved breeder production and egg quality and reduced breeder jejunal inflammation while maintaining tibial development in comparison to those receiving higher inorganic mineral supplementation, and it also carried over the benefits to progeny with better growth performance, less jejunal inflammation and better innate immune response and gut barrier function in comparison to ITM and/or TMAAC.

Chemistry and U–Pb geochronology of cassiterite in the Xiasai deposit, central Yidun Terrane (SW China): Link between Sn and Ag–Pb–Zn mineralisation

Tin and (Ag)–Pb–Zn mineralisation generally co-exist in SEDEX, porphyry, skarn, greisen, as well as magmatic-hydrothermal Sn and/or Pb–Zn polymetallic deposits. The genetic relationship between these two styles of mineralization, however, is not well defined. More than 20 skarn and hydrothermal-vein-type Ag–Pb–Zn–Sn deposits can be found in the central Yidun Terrane (YDT) of southwestern China. Amongst these is the large Xiasai deposit, which contains 1028 t Ag @ 337.8 g/t, 0.27 Mt Pb + Zn @ 8.33 %, and 20,000 t Sn @ 0.75 %. The deposit is zoned, comprising proximal cassiterite-quartz veins and distal Ag–Pb–Zn veins. We present micro-textural studies, LA–ICP–MS U–Pb dating results, as well as cassiterite major and trace element data that served to better constrain the link between the Sn and Ag–Pb–Zn mineralisation at Xiasai. Two types of cassiterite, i.e., Cst I and Cst II, can be distinguished using cathodoluminescence (CL) imagery. Cst I has a dull luminesce and oscillatory zonation, and it has been partially replaced by Cst II, which has a bright luminesce and a homogeneous texture. Whistle the SnO2 and TiO2 contents of Cst I and Cst II are similar, the latter has slightly higher FeO compositions (from bdl to 0.08 wt% and 0.01 to 0.11 wt%, respectively). LA–ICP–MS U–Pb dating of cassiterite yielded a Tera-Wasserburg U–Pb lower intercept age of 99.2 ± 0.8 Ma (n = 39, MSWD = 1.8), identical to the ages of granitic magmatism and Ag–Pb–Zn vein formations. LA–ICP–MS trace element analyses revealed that cassiterite is enriched in Ti and W, but depleted in Fe, Mn, Nb, and Ta. The Zr/Hf ratios of cassiterite range from 4.7 to 15.8 and Ti/Zr ratios range from 1.8 to 6.2. Overall, the measured Fe, W, Nb, and Ta concentrations, as well as the calculated Zr/Hf and Ti/Zr ratios, indicate that the cassiterite-quartz veins at Xiasai have a magmatic-hydrothermal origin. Our findings, when combined with previous micro-thermometrical fluid inclusion data (423–481 °C for Sn and 158–386 °C for Ag–Pb–Zn mineralisation), suggest that Sn and Ag–Pb–Zn mineralisation was cogenetic and linked to a common magmatic-hydrothermal system. The spatial relationship between Cretaceous A-type granitic magmatism and Ag–Pb–Zn–Sn mineralisation in the central YDT can be used as a guideline for mineral exploration of both skarn and hydrothermal veins.

Ore forming and reworking processes in the Xitieshan Pb–Zn deposit, Qinghai Province, China: Constraints from in situ trace-element and S isotope compositions of sulfides

Although volcanogenic massive sulfide (VMS) deposits always form in extensional settings, many have been reworked by metamorphism, deformation, and the circulation of hydrothermal fluids during subsequent accretionary events. The genesis of VMS deposits has been well documented, however, the mechanisms that rework the mineralization have been relatively poorly constrained. An understanding of these mechanisms, though, is critical to the development of robust mineral deposit models as they are capable of remobilizing ore-forming metals. The Xitieshan Pb–Zn deposit, located in Qinghai Province, western China, is the third largest Pb–Zn deposit in China, with a total Pb–Zn metal reserve of 6.4 million tons. The occurrence of laminated and non-laminated orebodies in the Xitieshan deposit make it an ideal candidate to i) constrain the effects of metamorphic and hydrothermal processes on remobilization of metals in these base-metal systems, and ii) assess the genetic nature of this deposit. This is accomplished here by integrating new S isotope data and trace-element chemistry of sulfides from laminated ores with previous information on regional and deposit geology, and deformation characteristics preserved by the mineralized system. The S isotope composition of pyrite and sphalerite grains from laminated ores are consistently positive and range from 2.08 ‰ to 5.81 ‰, indicative of mixing of reduced sulfur from three distinct sources — volcanic rocks, seawater and thermochemical reduced sulfate, which is typical of VMS deposits globally. Greigite (Fe3S4) grains in laminated ores exhibit oscillatory zonation with respect to Cu, Co, Mn, Sb, and Tl concentrations; such compositional variations indicate that at least some of the primary VMS mineralization characteristics have been preserved despite subsequent reworking by metamorphism, deformation, and hydrothermal circulation. Combined with the results of previous studies, a two-stage genetic model is proposed for the formation and modification of the Xitieshan Pb–Zn deposit — i) initial formation of the primary Pb–Zn mineralization with minor of Cu, and ii) subsequent metamorphism and hydrothermal reworking of the deposit, which did not completely destroy the textural and chemical characteristics of the primary mineralization.

Re Variation Triggered from the Paleo-Pacific Plate Evolution: Constrains from Mo Polymetallic Deposits in Zhejiang Province, South China Mo Province

Although highly dispersed, critical Re metal has attracted lots of attention from geoscientists, the controlling factors of Re-content variation are not completely understood, especially with regards to the genetic relationship between Re-bearing Mo polymetallic deposits and plate subduction evolution. It is well documented that the South China Mo Province, in Zhejiang Province, is characterized by multi-stage Mo polymetallic mineralization associated with Paleo-Pacific plate subduction. The Xianlin Mo(Cu)–Fe deposit occurs in Western Zhejiang as porphyry mineralization or skarn mineralization between the granodiorite and limestone. Zircon U–Pb analysis of the ore-forming granodiorite yields a Concordia age of 150.8 ± 1.1 Ma. Six molybdenite samples have relatively high Re contents (128.9~155.7 ppm) and deliver a weighted mean model age of 149.6 ± 1.3 Ma. These geochronological data suggest the Xianlin polymetallic mineralization was genetically related to the granodiorite in the Late Jurassic. Moreover, a new compilation of reliable Re contents and Re–Os isotope age data in Zhejiang Province indicates a decreasing trend in Re contents of molybdenite from the Jurassic Fe-/Cu-dominated Mo mineralization stage to the Cretaceous PbZn-enriched Mo mineralization stage in the South China Mo Province. Based on previously proposed models relating tectonic, magmatic, and hydrothermal processes, it is suggested that the Jurassic Re-enriched Mo mineralization, associated with I-type granitoids, formed in a compressive setting during the low-angle subduction of the Paleo-Pacific slab, whilst the Cretaceous Re-poorer Mo/Mo–Pb–Zn mineralization, related to both I- and A-type granitoids, formed in an extensional back-arc setting triggered by the rollback of the Paleo-Pacific slab.

Phytochemical screening, Gas chromatography: Mass spectrometry and antidiabetic properties of aqueous extract of ginger (Zingiber officinale) in Alloxan induced diabetic Wistar rats

The study investigates the phytochemistry, Gas-Chromatography–Mass Spectrometry (GC-MS), atomic Absorbtion spectroscopy (AAS) and antidiabetic activities of aqueous ginger (Zingiber officinale) extract in diabetic alloxan-induced Wistar rats. Qualitative phytochemical analysis, GC-MS, AAS and antidiabetic properties of the aqueous ginger extract were determined using standard procedures. Phytochemical analysis of the aqueous ginger extract shows that the extract contains tannins, flavonoids, saponins, alkaloids, simple phenolic, glycosides, carbohydrates, reducing sugar and steroids. The GC-MS study of the aqueous Zingiber officinale extract revealed the presence of eleven different compounds with 1,3-Cyclohexadiene, 5-(1,5-dimethy 4-hexenyl)-2-methyl-, [S-(R*,S*)]- been the most abundant with peak area of 33.98%. The AAS analysis shows that ginger contain: Ca, Na, Fe, K, P and Zn minerals. Twenty five (25) Wistar rats were grouped into 5 groups and investigated for antidiabetic study for a period of 15 days. Group A and B animals were normal and negative control respectively. Group B rats were induced with alloxan and not treated with drugs or extract. Animals in other groups (C, D and E rats) were diabetic and treated with standard drug (glibenclamide with concentration of 10 mg/kg), 200 and 400 mg/kg body weight of aqueous ginger extract respectively. The group of rats treated with 10, 200 and 400 mg/kg body weight of glibenclamide and aqueous ginger extract showed significant reduction (p

Ore-forming environment of Pb−Zn mineralization related to granite porphyry at Huangshaping skarn deposit, Nanling Range, South China

Multiple metallogenic types (skarn-type and vein-type) related to hypabyssal granites are found at the Huangshaping polymetallic deposit in the Nanling Range, South China. To constrain the crystallization and mineralization processes of skarn formation, three generations of magnetite and pyrrhotite from the hydrous silicate stage, oxide stage, early quartz–sulfide stage, and late quartz–sulfide stage were distinguished. The geochemical compositions of magnetite and pyrrhotite were obtained by electron probe microanalyzer (EPMA) and in-situ ablation−inductively coupled plasma−mass spectrometry (LA-ICP-MS). The results show that there may be silicate inclusions in magnetite and interaction of wall rock occurred in the mineralization process. The geochemical trends recorded in pyrrhotite show the influence of limestone during the crystallization of pyrrhotite. The re-equilibration temperatures of Po I, Po II, and Po III are 420.46, 380.45, and 341.81 °C, respectively, which suggests a continuous evolution following the high-temperature W–Sn mineralized system. The content change of Ni and V reflects a gradual decrease of oxygen fugacity from Mag I to Mag III, while the sulfur fugacity calculated from pyrrhotite gradually decreases. This continuous skarn mineralization evolution process helps us to better understand the change of metallogenic environment in the retrograde stage of the Huangshaping deposit.

Combination of low-accumulation kumquat cultivars and amendments to reduce Cd and Pb accumulation in kumquat grown in contaminated soil

Kumquat, the main economic fruit of Guangxi, China was selected as the research object of this study. Pot and field experiments were conducted to systematically study the safe utilization of Cd- and Pb-contaminated orchard soil, which is a typical karst zone surrounding a historical Pb–Zn mining area in Yangshuo County, Guilin City, Guangxi Province. The pot experiment compared the Cd and Pb accumulation ability of different kumquat cultivars. The results showed that Cuipi (CP) had a lower Cd and Pb accumulation ability. Compared with Yingmu (YM), the Cd and Pb contents of CP leaves were reduced by 39.71% and 32.83%, respectively. In the field experiment (one year), CP with low accumulation was combined with 0.5% amendments including rice husk biochar (RB), pig manure (PB), soil conditioner (SC), and organic fertilizer (OF) in real Cd- and Pb-contaminated kumquat orchard soils. The results showed that all amendments reduced non-carcinogenic health risks and improved agricultural sustainability. In terms of health risk reduction, the amendments significantly reduced the accumulation of Cd and Pb in fruit of CP. In particular, RB decreased Cd and Pb by 76.90% and 25.59%, respectively, achieving the highest health risk reduction (37.16%). Moreover, RB is more advantageous owing to its low cost. To determine agricultural sustainability, the soil quality and kumquat production were evaluated. After adding amendments, the available Cd and Pb contents in soil decreased by 42.19–60.94% and 41.64–57.79%, respectively. SC and OF improved soil quality more effectively, while RB increased the fruit biomass and the basic quality of CP. Comprehensive analysis, RB has more advantages. The mechanism of immobilization by the different amendments was further analyzed. RB and OF primarily immobilized the heavy metals by adsorption, and that of SC and PB mainly due to adsorption and precipitation. This study provides a theoretical and practical basis for the remediation of heavy metal-contaminated orchard soil.

Wastewater irrigation: An opportunity for improving soil phosphorus availability; PHREEQC modeling and adsorption studies

Wastewater, an alternative supply of water and nutrients, is being allocated as a priority for human population sustainability in arid and semi-arid regions. This work proposes phosphorus (P), a vital growth-limiting nutrient, adsorption behavior in wastewater irrigated agricultural soils in comparison to non-irrigated soils using laboratory batch experiments. The adsorption mechanism was assessed using different adsorption isotherm models. Saturation indices were modeled, using the hydro-geochemical transport code PHREEQC and MINTEQ geochemical software. Phosphorus buffering parameters were also calculated based on the standard equations. The equilibrium data were well fitted with the Freundlich isotherm model. The physical adsorption mechanism was found based on the calculated isotherm parameters. The maximum adsorption capacity was two times more in non-wastewater irrigated soils than irrigated. Results highlighted the effectiveness of wastewater irrigation in P availability in soil. Based on the PHREEQC modeling data, precipitation of Pb and Zn mineral phases was probable in soils by wastewater influence. Meanwhile, the precipitation of stable calcium phases, that affect the P sorption and/or co-precipitation, in non-wastewater irrigated soils was highlighted in the PHREEQC calculations. The standard buffer capacity (SBC) was 43 and 64 L kg−1 in wastewater irrigated soils and non-irrigated soils, respectively. Findings of the present study demonstrate the importance of wastewater reuse opportunities for agricultural application, especially soil P availability, and are helpful to minimize the environmental impacts of wastewater and solid waste.

Characterization and genesis of supergene karstic vanadium ores in the Djebba Pb–Zn district (Triassic Diapirs zone, North Eastern Tunisia)

The Djebba district hosts hypogene Pb–Zn sulfides and two successive stages of supergene Pb–Zn–Fe–V mineralization. This study mainly focuses on the supergene karstic vanadium mineralization of Jebel Goraa deposit. The hypogene Pb–Zn mineralization is considered to have been formed during Late Miocene (Alpine Orogeny) by Mississippi-Valley-Type (MVT) brines, similar to that proposed for many other Pb–Zn ore deposits of the Diapirs zone in Northern Africa. During the Late Neogene-Pleistocene, several episodes of uplift and erosion enabled the exhumation and karstification of the Early Eocene host rocks, and spatially related hypogene Pb–Zn-(Fe) sulfides, their subsequent weathering, and the formation of supergene ores. Vanadium mineralization is developed in karst cavities filled with oxidized ores (goethite, smithsonite and hemimorphite) and argillaceous materials (smectite). The paragenesis of supergene ores reveals two successive stages of deposition: 1) early supergene weathering with formation of Fe-bearing carbonates in turn oxidized to goethite, smithsonite, hemimorphite, and cerussite; 2) late supergene weathering with deposition of Pb–Zn vanadate minerals (vanadinite, descloizite, and vanadinite-pyromorphite intermediate compositions), minor mimetite and late calcite.Vanadium, phosphorous and probably chlorine of the vanadate ores are inferred to have originated from the immature organic matter of Early Eocene country rocks (Tmax <435 °C and TOC average 3.4 wt%) by descending low-temperature aqueous solutions. Pb, Zn and minor As were derived from primary Pb–Zn sulfides undergoing oxidation. Genesis of supergene vanadium ores is genetically related to post-Miocene uplifting-related weathering episodes, controlled by tectono-morphological and climatic evolution following the Alpine orogeny. The formation of the vanadium mineralization spans through the Late Miocene to Holocene. However, with paleoclimatic considerations it could be generally confined to the Middle Pliocene. Genetically, the supergene vanadium ores of Djebba Pb–Zn district belong to the vanadate ores type, which have been reported in other areas of southern and northern Africa (e.g., Namibia and Morocco). The association of vanadium, particularly in highly fractured and faulted zones with high levels of immature organic matter and spatially close to surface or near-surface MVT Pb–Zn ore deposits, can be used as an exploration tool for new vanadium-bearing deposits.

Influence of minor Zn additions on grain boundary anelasticity, grain boundary sliding, and superplasticity of Al-Mg-based alloys

Al-Mg alloys (AA5083-type) are widely used for superplastic forming. Limited grain boundary sliding as compared to other superplastic alloys limits the formability of Al-Mg based alloys. Grain boundary sliding intensity depends on the grain size, grain boundaries structure, and chemical composition of alloys. To improve superplastic properties of Al-Mg based alloys, we investigated the influence of a minor addition of Zn on the grain boundary relaxation effect and grain boundary sliding ability. The temperature dependence internal friction, superplastic deformation behavior, and microstructural changes during superplastic deformation for the AA5083 alloy and Zn modified alloy were compared. A minor Zn addition of 0.7 wt% does not influence the mean grain size but decreases the relaxation strength and the activation energy of grain boundary relaxation. The mechanisms of superplastic deformation and their contributions to the total strain were analyzed using FIB-milled grids evolution on the samples’ surface. Grain boundary sliding, grain rotations, and intragranular strain included both dislocation slip/creep and diffusional creep were involved in the deformation process. The contribution of grain boundary sliding increased from 10% to 25% for the Zn-free AA5083 alloy to 30–50% for the Zn-modified alloy. In result, a minor Zn addition proved to stimulate grain boundary sliding that decreases stress and increases strain rate sensitivity and elongation-to-failure of the studied alloy.

Ore genetic implications of pyrite and sphalerite compositions fromRajpura‐Daribaand ZawarmalaPb‐Zndeposits, Northwestern India

Pb–Zn mineralization at Rajpura‐Dariba and Zawarmala, India, is hosted in the Palaeoproterozoic meta‐volcano‐sedimentary sequence of Aravalli‐Delhi Belt. We have studied different generations of pyrite (Py‐I, II and III) and sphalerite (Sph‐I, II and III), associated with ore mineralization and remobilization stages, from both the deposits. In Rajpura‐Dariba, high concentrations of the majority of trace elements in syngenetic Py‐I and Sph‐I suggest their formation from trace element enriched hydrothermal fluid in SEDEX environment. Enrichment of lattice bound elements in Py‐II (As, Co, Ni) and Sph‐II (Mn, Hg and Cd) during metamorphic recrystallization of early pyrite and sphalerite indicates their local derivation from host rocks. The Pb, Tl, Ag and Sb rich Py‐III and Sph‐III in discordant ore indicate their crystallization from low melting‐point chalcophile elements enriched sulfide melt. In Zawarmala, the trace element poor natures of diagenetic banded Py‐I and Sph‐I suggest that the initial ore‐forming fluid was depleted in trace elements. Enrichment of trace elements in Py‐II (As, Mn, Tl, Cu) and Sph‐II (Mn, Hg, As, Ga) in sphalerite‐pyrite vein ore signify their derivation from carbonate host rocks. The high abundance of trace elements in Py‐III and Sph‐III indicates their precipitation at lower temperatures from a trace element enriched hydrothermal fluid during the massive galena‐sphalerite ore formation. Pyrite and sphalerite from global SEDEX are trace elements enriched as compared to MVT deposits, where their compositions have remarkably correlation with host rocks. Our study highlights the influence of host rock in pyrite and sphalerite compositions and their ore genetic implications.

Two-stage Cu[sbnd]Pb[sbnd]Zn mineralization of the Baoshan deposit in southern Hunan, South China: Constraints from zircon and pyrite geochronology and geochemistry

The Baoshan CuPbZn deposit is one of the representative polymetallic deposits in the middle of the Nanling Range, the western part of the Qin–Hang ore belt. In order to better understand the magmatic activity (granodiorite porphyry and porphyritic granodiorite) and mineralization in the Baoshan deposit, in situ UPb and LuHf isotope studies of zircons and trace element compositions of two generations of pyrite (ore stage: Py I and post-ore stage: Py II) have been carried out. This constrains the geochronology, magma source, fluid composition, and the origin of the ore-forming materials. The zircon UPb dating results from two types of intrusions show two geochronological populations: (i) ~180 Ma for the Cu (PbZn) mineralization that is related to the porphyritic granodiorite, and (ii) ~160 Ma for the CuPbZn mineralization which is associated with the granodiorite porphyry. The similar REE patterns, Hf/U, Nb/Ta, and Y/Ho ratios along with Hf isotopic characteristics of both granite types indicate that these rocks were sourced from the partial melting of lithospheric mantle and lower crust. Zircons from the granodiorite porphyry have higher Nb, Ta, Lu, and Hf contents, but lower Ti contents and Th/U ratios than those from the porphyritic granodiorite, suggesting that the magma-forming granodiorite porphyry had lower temperature, higher oxygen fugacity, and probably experienced strong crystal fractionation. Py I and Py II are associated with the porphyritic granodiorite and are related to the mineralization that occurred at ~180 Ma. The composition of pyrite in the two stages indicates the contribution of granite and limestone to mineralization. The higher contents of metals (Cu, Pb, Zn, Bi, Ag, except Co and Ni) in Py I than in Py II indicate the cooling and mixing process of ore-forming fluid with meteoric water. The geochemical characteristics of the pyrite generations and UPb dating of zircons suggest that the small-scale mineralization occurred at ~180 Ma under a relatively high-temperature and lower oxidized magmatic environment, whereas the major metallogenic event occurred at ~160 Ma under a low-temperature, medium oxidized, and strongly fractionated magmatic environment. This study reveals that the multi-stage magmatic and mineralization processes mainly occurred during the Early to Late Jurassic in South China.