Gold Research Articles

EVIDENCES OF MINERAL MELTING IN THE ORES OF THE SVETLINSK GOLD DEPOSIT, SOUTH URALS, RUSSIA

For the large Svetlinsk gold deposit (South Urals) evidences of partial melting of minerals and possible participation of polymetallic melts in the concentration and redistribution of gold and other metals are given. Finding of bismuth and antimony minerals in ores, among which there are gold minerals new to the deposit (pampaloite, montbrayite and aurostibite), specific mineral intergrowths (polymineral Sb–Bi–Pb–Te–Ag–Au drop inclusions), enrichment of early sulphides with Low-Melting-point Chalcophile Elements (LMCE), high formation temperatures for ore assemblages (up to 400°C), as well as the occurring metamorphism of amphibolite facies indicate the possibility of the formation of such melts. Polymetallic melts at the deposit could be formed both by partial melting of early sulphides and directly from hydrothermal fluids. The signs of melting also include simplectites of calaverite and native gold in the marginal parts of the large montbrayite grain.

Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

Anticancer Potential of Hemidesmus indicus-enriched Pt/Au Bimetallic Nanoparticles against Human Breast and Skin Cancer Cell Lines

Background: Worldwide, cancer has become the most disastrous disease, causing an enormous number of deaths in the population. According to GLOBOCON, in the year 2020, there were 1.93 crore cases of cancer reported and 10 million deaths caused by cancer. Methods: Metallic nanoparticles, such as gold, silver, and platinum, which possess properties of bioenvironmental stability, safety, and lower toxicity, have become preferred materials for drug delivery. Bimetallic nanoparticles, in particular, have shown enhanced optical, magnetic, electrical, catalytic, and medicinal properties compared to monometallic nanoparticles. We have developed goldplatinum PtAuBNPs containing H. indicus methanolic extract using a green synthesis approach. The PtAuBNPs were characterized by UV-visible spectroscopy, particle size analysis, zeta potential measurement, and surface characteristics using TEM, XRD, Raman spectroscopy, and DSC. The anticancer activity of PtAuBNPs was investigated using two distinctive cell lines, MCF-7 and B16F10. Results: The change in the colour of the prepared systems after incubation indicated the development of nanoparticles, as analysed by UV spectroscopy. The PtAuBNPs showed a particle size of 243.3 nm and a zeta potential of -14.4 mV. TEM analysis showed the hexagonal and cubic nature of the nanoparticles. XRD analysis indicated the crystalline nature of the nanoparticles. The bimetallic nanoparticles showed greater anticancer activity against the breast cancer cell line (MCF-7) and the skin cancer cell line (B16F10), with IC50 values of 35.52µg mL-1and 30.22 µg mL-1, respectively, which have been found to be lower than the standard 5-FU. Conclusion: The development of PtAuBNPs may pave the way for a new era of enhancing the anticancer activity of herbal extracts through the synergistic effects of gold and platinum metals. The developed PtAuBNPs have been shown to exhibit excellent anticancer activity against skin and breast cancer.

Surface Plasmon Resonance (SPR)-Based Multimode Optical Fiber Sensors for Electrical Transformer Oil Aging Detection

I In this study, optical fibers were designed and implemented as a chemical sensor based on surface plasmon resonance (SPR) to estimate the age of the oil used in electrical transformers. The study depends on the refractive indices of the oil. The sensor was created by embedding the center portion of the optical fiber in a resin block, followed by polishing, and tapering to create the optical fiber sensor. The tapering time was 50 min. The multi-mode optical fiber was coated with 60 nm thickness gold metal. The deposition length was 4 cm. The sensor's resonance wavelength was 415 nm. The primary sensor parameters were calculated, including sensitivity (6.25), signal-to-noise ratio (2.38), figure of merit (4.88), and accuracy (3.2). In the current study, the refractive index values of sucrose and water solutions at different concentrations, which were used as a calibration method, were calculated to be (1.346, 1.359, 1.382, and 1.39). It was found that when the refractive index of the sensitive medium increases, the length of the resonant wavelength increases due to the decrease in energy.

Thermal Behavior of Biaxial Piezoelectric MEMS-Scanners

This paper presents the thermal behavior of non-resonant (quasi-static) piezoelectric biaxial MEMS scanners with Bragg reflectors. These scanners were developed for LIDAR (LIght Detection And Ranging) applications using a pulsed 1550 nm laser with an average power of 2 W. At this power, a standard metal (gold) reflector can overheat and be damaged. The Bragg reflector developed here has up to 24 times lower absorption than gold, which limits heating of the mirror. However, the use of such a reflector involves a technological process completely different from that used for gold and induces, for example, different final stresses on the mirror. In view of the high requirements for optical power, the behavior of this reflector in the event of an increase in temperature needs to be studied and compared with the results of previous studies using gold reflectors. This paper shows that the Bragg reflector remains functional as the temperature rises and undergoes no detrimental deformation even when heated to 200 °C. In addition, the 2D-projection model revealed a 5% variation in optical angle at temperatures up to 150 °C and stability of 2D scanning during one hour of continuous use at 150 °C. The results of this study demonstrate that a biaxial piezoelectric MEMS scanner equipped with Bragg reflector technology can reach a maximum temperature of 150 °C, which is of the same order of magnitude as can be reached by scanners with gold reflectors.

Advances in E-Waste Recycling: Physical and Chemical Treatment Methods

The unprecedented rise in production and consumption of electronic devices has resulted in staggering amounts of electronic waste (e-waste). Improper recycling and disposal of e-waste can cause severe environmental and public health repercussions due to the presence of toxic substances like lead, mercury, and flame retardants. This article introduced advanced e-waste recycling technologies, focusing on physical and chemical treatment methods. Physical treatments such as gravity separation, electrostatic separation, and inverse flotation enable efficient and cost-effective recovery of precious metals like gold, silver, platinum, and rare earth metals from e-waste components. These physical processes are often environmentally friendly, scalable, and can handle diverse e-waste streams. Chemical treatments, including the dimethylformamide technique, supercritical fluid technique, and pyrolysis, allow for separating hazardous substances and recovering valuable materials not amenable to physical processes. Supercritical CO2 fluid destroys toxic organic compounds while enabling metal recovery. Pyrolysis converts plastics into liquid oil and gas products. By enhancing the separation and purification of valued materials, these physical and chemical e-waste recycling techniques provide more profitable, efficient, and sustainable solutions to ever-growing e-waste volumes.

Physico-Chemical Alternatives for Synthesis of Metal Nanoparticles Using Fusarium Chlamydosporum

Abstract Introduction/Objective Background: Synthesizing metal nanoparticles (NPs) by chemical or physical methods is difficult due to energy and time consumption, equipment costs, and chemical toxicity. Chemosynthesis-derived NPs are unstable, limiting their biological applications. Thus, identifying alternative green sources to address these drawbacks is difficult scientifically. The hardest part of green metal nanoparticle synthesis is finding a nontoxic natural product and an eco-friendly solvent. Objectives: Isolation of fungal endophytes from Eucalyptus sideroxylon leaves to synthesize ZnO and Au nanoparticles. Methods/Case Report Materials and methods: We used healthy Eucalyptus sideroxylon plant samples from the desert research center to separate endophytes. All fungi were grown on malt extract broth on a rotary shaker at 28 °C (120 rpm) for 96 hours after isolation. Biomass components were removed by filtration and washing in distilled water. Nanoparticles came from biomass cell filtrate. 0.1 M, 1 mL of Zn SO4, and HAuCl4 were added to 10 mL of fungal filtrate and agitated for 24 hours in the dark at room temperature to make Zn and Au nanoparticles separately. Characterization of nanoparticles shows a green synthesis of ZnONPs and AuNPs. Results (if a Case Study enter NA) Results: Fungal endophytes' filtrates were mixed with 1mM Zn SO4 and HAuCl4 solutions to test their extracellular biosynthesis of ZnO and Au NPs. The fungal filtrate became colorless and violet after mixing with Zn SO4 and HAuCl4. Only FI-03 is from 13 (FI-01 to FI-013). The most potent fungal strain for Zn O NP and Au NP nanoparticle synthesis was Fusarium Chlamydosporum. Pure, mostly spherical ZnO and Au NPs averaged 19.3 and 22.1 nm. UV-Vis absorption: Excitonic absorption peaks of ZnO NPs were between 300 and 400 nm. ZnO NPs' maximum absorption peak was 305 nm, while Au NPs' peak was 520 nm. One absorption peak indicates metallic gold nanoparticles. Au and ZnO NPs aggregate the most due to their hydrophilicity, HD of 34.88 and 15.77 nm, and PdI of 0.77, 1.00, and 0.952. Gold face-centered cubic fcc structure dominates Au NPs' XRD pattern. EDX shows 64.61 and 35.39 percent Zn and O, respectively, in both nanoparticles. The optical absorption band of gold nanocrystallites peaked at 2.2 keV in energy-dispersive X-rays. Conclusion Endophytic fungus biosynthesizes ZnO and Au NPs, which are bioactive compounds for medicine and food without toxic chemicals and are environmentally friendly.

Slag chemistry, element distribution behaviors, and metallurgical balance of e-waste smelting process

The co-smelting of electronic waste (e-waste) in copper/lead pyrometallurgical processes is widely recognized as the preferred solution for sustainable development. However, aluminum and halogen elements in e-waste causes new challenges. To address this, the slag chemistry of high Al2O3-containing slag was studied, and the distribution behaviors of Au, Ag, Sn, and other elements in the copper alloy/slag/gas system were investigated in the presence of halogen elements (F/Cl/Br) using the equilibration method. The industrial practice of electronic waste smelting was modeled using METSIM, and the material and energy balances of one industrial process were obtained. Under the conditions of electronic waste smelting, the solubility of Al2O3 in the FexO–SiO2–Al2O3–CaO slag system decreased with increasing CaO content. When the CaO content was 20 wt%, and the Fe/SiO2 mass ratio was 0.62–0.95, the solubility of Al2O3 in the slag reached 20 wt%. When 1%–10% CaF2 was added, 93% of Au entered the metal phase. When the same amount of CaCl2 or CaBr2 was added, up to 32% Au entered the gas phase. When CaF2 was added to the system, 22%–49% of Ag entered the gas phase. However, when CaCl2 or CaBr2 was added, 3%–34% of Ag entered the gas phase. The proportion of tin in the gas and slag phases increased with increasing temperature or the addition of halides. The METSIM simulation results showed that under optimized conditions, the crude copper contained more than 90 wt% copper, the discharged slag contained approximately 0.5 wt% copper, and the recovery rates of copper, gold, and silver were ≥98%. The heat generated from raw materials and fuel accounted for the largest part of the heat income, representing 65.32% of the total.

High efficiency design of metal–insulator–metal metasurface by ResNets-10

Deep learning prediction of metasurface has been a widely discussed issue in recent years. However, the prediction accuracy is still one of the challenges to be solved. In this work, we proposed using the ResNets-10 model to predict plasmonic metasurface S11 parameters. The two-stage training was performed by the k-fold cross-validation and small learning rate. After the training was complete, the predicted logarithmic losses for aluminum, gold, and silver metal–insulator–metal metasurfaces were −48.45, −46.47, and −35.54, respectively. Due to the ultralow error value, the proposed network can efficiently replace the traditional computing methods within a certain structural range. The ResNets-10 can complete training within 1100 iterations, which is highly efficient. The ResNets-10 model we proposed can also be used to design meta-diffractive devices and meta-resonance biosensors, thereby reducing the time required for the simulation process. The ultralow lose value of the network indicates that this work contributes to the development of future artificial intelligence electromagnetic devices computing software.

Fruits and plants, grains and seeds, birds, precious metals, and substances, or the conceptualization of colors in Tunisian Arabic

Abstract Two opposed views dominate the color scene: Universalism and relativism. Each view has been shown to have fallen short of fully accounting for color perception and naming across languages and cultures. Beyond this controversy, the current article proposes cultural neuroscience as an alternative view to account for color naming and the conceptualization of experiences in color terms in Tunisian Arabic (TA). Cultural neuroscience accumulated massive cross-cultural empirical evidence to the effect that culture greatly impacts brain and cognition. The current article will draw on cultural neuroscience to explain the central role played by culture in shaping cognition and language. Thus, the argument will run as follows: The language in which color is cloaked owes much to experience in social cognition, which is greatly impacted by the cultural environment. This view implies that color naming is under the influence of the cultural needs of color users and cognizers in their respective cultures, with the language they speak as ancillary to culture. In TA, there are 11 color terms, with five focal colors including multiple shades and a form in mes– (–ish), reminiscent of English brownish from brown. Color naming in TA is conceptualized in terms of names of fruits (oranges, apricots, peaches, dates), plants (Jew’s mallow), aromatic plants (lavender), grains (wheat), birds (canary), seeds (pistachio), precious metals (gold), and substances (honey, coffee, chocolate, ash). Color is also manifest as a source domain in various metaphoric and metonymic expressions to conceptualize experiences and events using verbal, nominal, and adjectival derivations.

Effects of alloy composition in traditional Japanese shakudo patination.

Japanese craftspeople have dominated the art of patinating copper-alloys since the 15th century, using precise alloy compositions and complicated patination processes in different hot solutions to create a variety of colours on swords fittings such as tsuba. While this complex tradition is increasingly popular in the East, the reasons behind the choices made by craftspeople in the selection of the components of the alloys and are still not fully understood. This paper investigates the effect of different alloying elements (tin, gold, and silver) on the resulting patina. Experimental results are compared with optical and compositional analyses on historical Japanese artefacts, confirming the effects of the different alloying elements on the patina characteristics and colour. The absence of tin and the presence of gold limit the growth of an oxide layer and promote the formation of a thin patina characterised by a smooth appearance without visible grains. Therefore, a limited thickness of the patinas is a key aspect for the production of the desired colour and appearance of the patinas. The first colorimetric analysis on historical Japanese artefacts demonstrates the influence of gold, silver and tin in the final patina colour, validating the observations in the experimental replicas.

Origin of the Dashuigou Independent Tellurium Deposit at the Southeastern Qinghai-Tibet Plateau: Based on the Abundances of Trace Elements in the Country Rocks

Through a detailed study of the abundances and spatial-temporal distribution patterns of Te, Bi, As, Se, Cu, Pb, Zn, Au, and Ag in the rock types of different geological epochs in the Dashuigou independent tellurium deposit, and in combination with other research findings of previous researchers in this area, the authors conclude as follows: Abundances of the main ore-forming elements Te, Bi, As, Se, Au, and Ag are not high in the regional geological background, generally lower or close to their respective crustal Clark values, but almost all altered country rocks contain high levels of ore-forming elements. This indicates that the deposit’s ore-forming elements do not come from the country rocks. This also indicates that the geological thermal events that cause alteration and mineralization originate from depths and may be related to mantle plumes. Considering the distribution pattern of these ore-forming elements in the ore bodies’ hanging wall and footwall, the metallogenic mechanism may be as follows: Mineralization is not achieved through lateral secretion in the horizontal or near horizontal direction, but rather through the upward movement and emplacement of deep ore-forming elements driven by geological processes such as mantle plumes. In addition, the migration of deep ore-forming elements is not achieved through dispersed infiltration between overlying rock particles, but through non widespread concentrated penetrating channels. This type of channel is likely to be the expansion structures where faults from different directions intersect, or where linear faults intersect with circular structures.

Spectroscopic insights into gold-cerium oxidation states influencing catalytic activity and selectivity in CeO2-supported gold during CO-PROX reaction

Here we present an investigation into the evolution of gold-cerium oxidation states in Au/CeO2 catalysts concerning Au content and its relationship between the influence of these oxidation states on catalytic activity and selectivity during the CO-PROX reaction. The Au-loading notably influences the electronic states of gold and cerium species. As gold content increases, metallic gold particles form, and their stability under reaction conditions decreases. Oxygen vacancies and dynamic oxygen storage capacity (OSC) increase at low gold loadings (0.32 wt.%). Catalytic activity depends on Au content, exhibiting higher CO2 selectivity at lower Au content (0.32 wt.%) under 120 °C. CO oxidation activity heavily depends on dynamic OSC, which is associated with oxygen vacancies. Selectivity depends on the specific electronic properties of catalysts. CO2 selectivity depends on the presence of cationic Au species. Meanwhile, H2 oxidation occurs on surfaces where a high content of metallic Au species is exposed on the catalyst surface.

Electrochemical Synthesis of Gold-N-Heterocyclic Carbene Complexes.

An electrochemical synthesis of gold(I)-N-heterocyclic carbene (Au-NHC) complexes has been developed. The electrochemical methodology uses only imidazolium salts, gold metal electrodes, and electricity to produce these complexes with hydrogen gas as the only by-product. This high-yielding and operationally simple procedure has been used to produce eight mononuclear and three dinuclear Au-NHC complexes. The electrochemical procedure facilitates a clean reaction with no by-products. As such, Au-NHC complexes can be directly transferred to catalytic reactions without work-up or purification. The Au-NHC complexes were produced on-demand and tested as catalysts in a vinylcyclopropanation reaction. All mononuclear Au-NHC complexes performed similarly to or better than the isolated complexes.

Structural Analyses of DP-1, a Protein with the Ability To Bind Gold Nanoparticles, by Using Nuclear Magnetic Resonance Spectroscopy.

Gold nanoparticles (AuNPs), consisting of metallic gold, are applied in various fields owing to their characteristic physical properties. Collimonas sp. D-25 (D-25) is a Gram-negative bacterium obtained from soil, compost, and other environmental materials in the Akita Prefecture. DP-1 is a water-soluble protein found in D-25 that binds specifically to AuNPs and retains them with high stability. This study aimed to identify the part of DP-1 that interacts with AuNPs and determine its 3D structure in solution using nuclear magnetic resonance spectroscopy. Peptide fragments obtained by trypsin digestion were examined for their AuNP-binding capacity to determine the key Au-binding domain of DP-1. A fragment consisting of 16 amino acid residues (GHAATPEQYGVVTANK) was identified as the peptide with the highest binding activity. Structural analyses of this peptide indicated that the main chain was elongated, and negatively charged residues in the side chain were exposed on the surface by incorporating AuNPs. These results suggest that DP-1 interacts with AuNPs through negatively charged residues and extended hydrophobic residues for protein-protein interactions. The structural data also provide new insights into biomimetic technologies.

Precious Metals and Oil Price Dynamics

The aim of this study is to examine dynamic relationship among the prices of four precious metals (gold, silver, platinum, and palladium), oil price, and the US dollar/euro exchange rate. Recent literature for precious metals (gold, silver, platinum, palladium) and oil depict a lot contradiction results of their nexus in the long and short runs. So that, there is still much to investigate and learn about their relationship between them and with the exchange rate. The monthly data span from January 1990 to October 2021 is utilized, the study applies the co-integration analysis, multivariate Granger causality test and Variance Decomposition (VDC) analysis. The result shows the evidence of a long-run equilibrium relationship but weak feedbacks in the short run. The precious metal markets respond significantly (but temporarily) to a shock in any of the prices of the other metal prices and the exchange rate. Furthermore, we discover some evidence of market overreactions in the palladium and platinum cases as well as in the oil market. The study implies whether there are overreactions and re-adjustments or not, investors may diversify at least a portion of the risk away by investing in precious metals, oil, and the euro.

Green Synthesis of Nanoparticles and Their Energy Storage, Environmental, and Biomedical Applications

Green synthesis offers a superior alternative to traditional methods for producing metal and metal oxide nanoparticles. This approach is not only benign and safe but also cost-effective, scalable, and straightforward, operating under ambient conditions. Notable metals and metal oxide nanoparticles, such as manganese oxides, iron oxides, silver, and gold, have been produced using various bio-reductants derived from plant extracts. These biological agents not only expedite the reduction process but also stabilize the nanoparticles, serving dual roles as reducing and capping agents. This review presents the green synthesis of nanoparticles (NPs) obtained from biogenic wastes and plant extracts. The green-synthesized nanostructured MnO2 nanoparticles are evaluated as a potential photocatalyst for water treatment and as an electrode material in lithium-ion batteries and supercapacitors. The green-derived iron oxide nanoparticles are examined as promising antioxidant, anti-inflammatory, and anti-diabetic agents. Additionally, this review discusses the green synthesis of precious metal nanoparticles, specifically silver (Ag NPs) and gold (Au NPs), highlighting their potential medical applications in areas like antiviral treatments and cancer therapy.

Effect of biogenic siderophores produced by Bacillus thuringiensis on gold and other element bioleaching from silicate ore

This comprehensive study delves into the role of silicate ore pretreatment and the biogenic siderophores produced by Bacillus thuringiensis in the bioleaching process of gold (Au) and various other elements. The results revealed that an effective pretreatment method involved subjecting silicate ore to ball milling (BM) at 200 rpm for 1 h, followed by ozonation (O3) for 10 min before initiating the bioleaching process. Subsequently, in the leaching of Au and other elements, the highest leachability was achieved through a two-step conditioning approach, involving the first and second stages of bioleaching with B. thuringiensis. The results strongly suggest that the mechanism of elements leaching is closely linked to the release of biogenic siderophores by B. thuringiensis, which possess remarkable potential as chelators and metal-binding agents, facilitating the formation of metal-siderophore complexes. Furthermore, the finding confirmed that commercial siderophores can effectively facilitate the leaching of Au and elements from silicate ore. Additionally, the presence of amino acids in nutrient broth (NB) medium provides the ability to bind with Au, forming Au-amino acids complexes. This finding underscores the effectiveness of the two-step conditioning approach with B. thuringiensis, particularly under mild alkaline pH conditions. This innovative technology offers numerous advantages, including its environmentally friendly and sustainable nature, safety, and cost-effectiveness. It presents a promising method for the efficient recovery of Au and other elements from pretreated silicate ore, especially those with low concentrations of valuable minerals, all through the remarkable capabilities of biogenic siderophores.

Trace element evidence for diverse origins of superheavy pyrite in Neoproterozoic sedimentary strata

Sedimentary pyrite has long been used as an archive of marine environments in Earth history. To capture reliable paleoenvironmental signals, however, we need to first evaluate pyrite in sedimentary strata as it can be altered and masked by later diagenetic and/or hydrothermal processes. Here, we trained two supervised machine learning algorithms on a large LA-ICP-MS pyrite trace element database to distinguish pyrite of different origins. The analysis validates that two models built on the co-behavior of 12 trace elements (Co, Ni, Cu, Zn, As, Mo, Ag, Sb, Te, Au, Tl, and Pb) can be used to accurately predict pyrite origins. Further statistical analysis suggests four trace element clusters behaving differently among sedimentary (syngenetic and early diagenetic), synsedimentary hydrothermal (syngenetic hydrothermal), and post-sedimentary hydrothermal (epigenetic hydrothermal) pyrite, which is probably driven by chemical and physical properties of source fluids, interactions between elements, competition among coprecipitating minerals, and pyrite growth rate. Armed with this initial success and aided by new LA-ICP-MS trace element data from 9 samples, we then demonstrated the efficacy of this approach in identifying the origins of pyrite from two Neoproterozoic sedimentary successions in South China. The first set of samples contain isotopically superheavy pyrite (i.e., whose bulk-sample δ34S values greater than those of contemporaneous seawater sulfate and whose origins remain controversial) from the Cryogenian Tiesi’ao and Datangpo formations. The second set of samples contain pyritic rims (associated with fossiliferous chert nodules and thought to be critical in exceptional fossil preservation) from the Ediacaran Doushantuo Formation. For the superheavy pyrite, the models consistently show high confidence levels (mostly > 80 % probability) in identifying its genesis type, and three out of four samples were given sedimentary origins. For the pyritic nodule rims, the models suggest that early diagenetic pyrite was subsequently altered by hydrothermal fluids and therefore shows mixed signals. The study highlights the importance of pyrite trace elements in deciphering and distinguishing the origins of pyrite in sedimentary strata.

Superimposed Gold Mineralization Events in the Tuanshanbei Orogenic Gold Deposit, Central Jiangnan Orogen, South China

Abstract The Jiangnan orogen, one of the largest gold-producing areas in China, has experienced multiple orogenic events with complex structural overprinting that is marked by multiple stages of magmatism, deformation, metamorphism, and orogenic gold mineralization. Different orogenic events have been recognized in the Neoproterozoic, mid-Paleozoic, Triassic, and Early Cretaceous, reflecting collisions and intracontinental orogenic episodes. The age of gold deposition in the Jiangnan orogen, however, has been poorly constrained owing to the absence of suitable dating minerals. Field studies in the orogen indicate the Tuanshanbei gold deposit includes two generations of auriferous quartz-ankerite-pyrite-arsenopyrite veins (Q2 and Q3), with the latter of the two notable for containing more abundant ankerite and base metal sulfides. The Q2 veins were formed throughout the near S-N–directed shortening associated with D1 deformation and along resulting subhorizontal to low-angle-dipping EW- to WNW-striking transpressive faults. The Q3 veins, containing about 70% of the total gold resource, were primarily localized in moderately to steeply dipping NW-striking tensional/tensional shear faults and moderately dipping NE- to NNE-striking transpressive faults that were products of NW-SE–directed shortening during D2 deformation. Both vein generations are temporally younger than the 437.2 ± 4.2 Ma Tuanshanbei granodiorite host, and both are crosscut by postgold ca. 225 Ma diabase dikes. Hydrothermal monazite coexists with native gold and gold-bearing metal sulfides in the Q2 and Q3 veins. The Q2 monazite yielded a Tera-Wasserburg lower intercept age of 415.1 ± 2.1 Ma, consistent within error with an ankerite Sm-Nd isochron age of 410 ± 15 Ma and a laser ablation-inductively coupled plasma-mass spectrometry hydrothermal zircon 206Pb/238U age of 411.2 ± 4.0 Ma. The Q3 monazite yielded a Tera-Wasserburg lower intercept age of 234.3 ± 1.1 Ma. These new ages suggest that the Early Devonian gold event was overprinted by hydrothermal activity along the same structural system almost 200 m.y. later such that the gold resource must be a product of two temporally distinct events. Geologic and structural evidence, coupled with existing published geochemical data, suggests both ore-forming events were related to crustal metamorphism typical of most orogenic gold deposits. Fluids would have been derived from Neoproterozoic metasedimentary basement rocks, most likely from metamorphic devolatilization of the Neoproterozoic Cangxiyan Group greenschist-amphibolite facies metasediments. There is no evidence suggesting any type of magmatic contribution to the ore-forming process at either time. The data are best interpreted to suggest that various parts of the basement were metamorphosed near the greenschist-amphibolite boundary at different times, but during both times, the gold-bearing metamorphic fluids eventually migrated into the same structural conduits.