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A comprehensive monitoring and risk assessment of arsenic (As) pollution concerning surface water and sediment is performed in the Jie River basin, where gold smelting enterprises are concentrated. The study area is divide into six regions, labeled as A, B, C, D, E, and F, from sewage outlets to downstream. Results shows that with far away from the sewage outlets, the total As concentrations in water and sediment gradually decrease from regions A to F. However, in region F, the concentration of bioavailable As significantly increases in the sediment due to the higher pH, leading to the transformation of As(V) into more mobile As(III). In sediment, Paracladius sp. exhibits strong resistance to As pollution in sediment, which can potentially elevate the risk of disease transmission. In water bodies, diatoms and euglena are the main phytoplankton in the Jie River while toxic cyanobacteria exhibits lower resistance to As pollution. Overall, measures should be taken to ecologically remediate the sediment in downstream while implementing appropriate isolation methods to prevent the spread of highly contaminated sediments from regions near sewage outlets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Research background: In order to examine market uncertainty, the paper depicts broad patterns of risk and systematic exposure to global equity market shocks for the major South Asian and Chinese equity markets, as well as for specific assets (gold and Bitcoin). Purpose of the article: The purpose of this paper is to investigate the dynamic correlation among the major South Asian equity markets (India and Pakistan), the Chinese equity markets, the MSCI developed markets, Bitcoin, and gold markets. Methods: While applying the GARCH-Vine-Copula model and the TVP-VAR Connectedness approach, major patterns of dependency and interconnectedness between these markets are investigated. Findings & value added: We find that risk shocks from developed equity markets are critical in these dynamic links. A net return spillover from Bitcoin to the Chinese and Pakistani stock markets throughout the sample period is reported. Interestingly, gold can be applied to hedge and diversify positions in China and major South Asian markets, particularly following the COVID-19 outbreak. Our paper presents three main original add valued: (1) This paper adds global factors to the targeted study of risk transmission among South Asian and Chinese stock markets for the first time. (2)The assets of Bitcoin and gold were added to the study of risk transmission among South Asian and Chinese stock markets for the first time, enabling the research in this paper to observe the non-linear link among the South Asian and Chinese stock markets with them. (3) Our research adds to these lines of inquiry by giving empirical evidence on how COVID-19 altered the dependent structure and return spillover dynamics of Bitcoin, gold and South Asian and Chinese stock markets for the first time. Our results have critical implications for investors and policymakers to effectively understand the nature of market forces and develop risk-averse strategies. [ABSTRACT FROM AUTHOR]

By studying both the microscopic physical and chemical typomorphic characteristics of typical mineral pyrite samples associated with representative gold deposits on the north-central margin of the North China Platform, this paper seeks to identify macroscopic metallogenic mechanisms of gold deposits and to reveal the formation mechanism of lattice gold in pyrite. Typomorphic characteristics of pyrite reveal that pyrite grain size has a negative correlation with gold content. Cubic pyrite, as the dominant crystal form, contains more gold than pentagonal dodecahedral pyrite. Both pyrite crystal forms and chemical compositions indicate that the replacement style of gold deposit formed in a low saturability, low sulfur fugacity, and at temperatures either much higher or much lower than its best forming temperature; comparatively, that of the quartz vein style of gold deposit occurred under conditions with the best temperature, rich in sulfur, and with high sulfur fugacity. The Au/Ag ratios of the pyrites show that both the replacement and quartz vein styles of deposits are mesothermal and hypothermal, while the Co/Ni ratios of the pyrites indicate that the quartz vein style is of magmatic-hydrothermal origin. The X-ray diffraction intensity of pyrite rich in gold is lower than that of pyrite poor in gold at the quartz vein style. In general, with an increase in gold content in pyrite, the total sum intensity ΣI decreases. The pyroelectricity coefficient has a negative correlation trend with the values of (Co + Ni + Se + Te)-As and (Co + Ni + Se + Te)/As. The pyrite pyroelectricity of the replacement style is N-type, indicating that it formed under low sulfur fugacity, while that of the quartz vein style is a mixture of P-N types, indicating that it formed under high sulfur fugacity. On the pyroelectricity-temperature diagram, pyrite of the replacement style is mainly distributed between 200 and 270 °C, while that of the quartz vein style varies between 90–118 and 274–386 °C, demonstrating a multistage forming process. In contrast to previous researchers' conclusions, the authors confirm the existence of lattice gold in pyrites through the use of an electron paramagnetic resonance (EPR) test. Au in the form of Au+, entering pyrite as an isomorph and producing electron–hole centers, makes the centers produce spin resonance absorption and results in EPR absorption peak II. The intensity of auriferous pyrite absorption peak II has certain direct positive correlations with pyrite gold content. The #I and #III absorption peaks of pyrites possibly result from the existence of Ni2+ and/or Cu2+. γ1, γ2, and γ3 are the strongest and most typical absorption peaks of the infrared spectra of the pyrites. Generally, with the increase in gold content in the pyrite samples, γ1, γ2, and γ3 tend to shift to higher wavenumbers, and the gold content in the pyrite samples has a positive correlation with their relative absorbance. [ABSTRACT FROM AUTHOR]

This paper focuses on the empirical analysis of the closing price of gold, the SSE Index, and the China Economic Policy Uncertainty Index by means of a GARCH model to study the main characteristics of their movements. The series of gold closing price returns are analysed for linkage using the current mainstream VAR model, so as to analyse and compare the hedging function of gold. The article selects the closing price of gold, the SSE Index, and the China News-Based EPU from June 2005 to June 2019 as the sample series for the study. The background of the study and the theoretical knowledge of VAR and GARCH models are first introduced, and then, the GARCH family model and statistical analysis methods are used to derive the respective movements of the log returns of gold closing price, SSE index log returns, and China News-Based EPU log volatilities. The results show that the movements of the closing price of gold, the SSE Index, and the China News-Based EPU have the characteristics of financial assets in general, such as spikes and thick tails, agglomeration, and leverage effects. For the empirical study of the linkage between the three, this paper first considers only three variables, namely gold closing price, SSE index, and EPU. In order to investigate whether there is a co-integration relationship between them, a vector autoregressive model is established, followed by the corresponding impulse response analysis and variance decomposition. The analysis of the linkage between the closing price of gold, the SSE index, and the EPU concluded that changes in the EPU had a greater impact on the changes in the closing price of gold, while changes in the SSE index had a smaller impact on the changes in the closing price of gold. Finally, the conclusion of this article is some advice to investors on gold investment., Competing Interests: The authors declared that they have no conflicts of interest., (Copyright © 2022 Borui Xiao.)

The formation of Carlin-type gold deposits is poorly constrained, mainly due to the lack of accurate ages for gold mineralization. The Youjiang basin, SW China, represents the world's second-largest Carlin-type gold province after NV, USA. In this paper, we use hydrothermal apatite U–Th–Pb dating to systemically determine the mineralization ages of five Carlin-type gold deposits, namely, Shuiyindong, Jinfeng, Zimudang, Linwang, and Jinya, in the Youjiang basin. The hydrothermal apatite is characterized by intimate intergrowth with gold-bearing sulfides, presence of primary fluid inclusions, irregular morphology and cathodoluminescence zoning, and MREE-enriched composition patterns, indicating that it is clearly associated and coeval with gold mineralization. The concentrations of lattice-bound U and Th in the apatite are highly variable, making it suitable for in situ secondary ion mass spectrometry (SIMS) U–Th–Pb dating. The dating results of hydrothermal apatite from the five deposits show that they formed at ca. 150–140 Ma, contemporary with the widespread felsic magmatism and associated W–Sn mineralization to the east of the Youjiang basin, probably in response to slab breakup of the Paleo-Pacific oceanic plate beneath the South China continental plate. Our case story suggests that hydrothermal apatite could be a robust chronometer for age dating of sedimentary rock-hosted gold mineralization worldwide. [ABSTRACT FROM AUTHOR]

This paper focuses on researching the scientific problem of deep extraction and inference of favorable geological and geochemical information about mineralization at depth, based on which a deep mineral resources prediction model is established and machine learning approaches are used to carry out deep quantitative mineral resources prediction. The main contents include: (i) discussing the method of 3D geochemical anomaly extraction under the multi-fractal content-volume (C-V) models, extracting the 12 element anomalies and constructing a 3D geochemical anomaly data volume model for laying the data foundation for researching geochemical element distribution and association; (ii) extracting the element association characteristics of primary geochemical halos and inferring deep metallogenic factors based on compositional data analysis (CoDA), including quantitatively extracting the geochemical element associations corresponding to ore-bearing structures (Sb-Hg) based on a data-driven CoDA framework, quantitatively identifying the front halo element association (As-Sb-Hg), near-ore halo element association (Au-Ag-Cu-Pb-Zn) and tail halo element association (W-Mo-Co-Bi), which provide quantitative indicators for the primary haloes' structural analysis at depth; (iii) establishing a deep geological and geochemical mineral resources prediction model, which is constructed by five quantitative mineralization indicators as input variables: fracture buffer zone, element association (Sb-Hg) of ore-bearing structures, metallogenic element Au anomaly, near-ore halo element association Au-Ag-Cu-Pb-Zn and the ratio of front halo to tail halo (As-Sb-Hg)/(W-Mo-Bi); and (iv) three-dimensional MPM based on the maximum entropy model (MaxEnt) and Gaussian mixture model (GMM), and delineating exploration targets at depth. The results show that the C-V model can identify the geological element distribution and the CoDA method can extract geochemical element associations in 3D space reliably, and the machine learning methods of MaxEnt and GMM have high performance in 3D MPM. [ABSTRACT FROM AUTHOR]

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To integrate the evidential signatures into a mineral prospective map, it is necessary to model the observed data of metallogenic predictors with complex relationships. In this paper, a methodology was developed for gold prospectivity modeling by combining Laplacian eigenmaps (LEMS) and the least angle regression (LARS). LEMS were used to transform metallogenic predictors into Laplacian spectra to enhance the data classification ability, and the Laplacian spectra were used in LARS for gold prospectivity modeling. The Jinchanggouliang area, an important gold metallogenic district in China, was taken as the study area. Based on the geological and geochemical survey data of the study area, the LARS model, the combination of LEMS and LARS (LEMS–LARS) model, the logistic regression (LGR) model and the one-class support vector machine (OCSVM) model were each established for gold prospectivity modeling in the study area. The performances of these four models were measured using different performance evaluation methods. The receiver operating characteristic (ROC) analysis reveals that the LEMS–LARS model, the LGR model and the OCSVM model yield comparable performances and were superior to the LARS model, for gold prospectivity modeling in the study area. The prediction–area (P–A) plots of the four models show that the LEMS–LARS model, the LGR model and the OCSVM model each predicted about 20% of the study area as gold prospective areas, which contain about 80% of the known gold deposit locations. However, the performance of the LARS model was difficult to evaluate by the P-A plot because its prediction curve overlaps with its area curve, forming a straight-line segment, in the P-A plot. The gold prospective areas delineated optimally separately by the LEMS–LARS model, the LGR model and the OCSVM model are associated spatially with areas having favorable metallogenic conditions. The case study illustrates that the LEMS–LARS model can be used as a data-driven mineral prospectivity method, and its performance, in gold prospectivity modeling in the study area, is comparable to that of the LGR method and OCSVM method. [ABSTRACT FROM AUTHOR]

A Paleoproterozoic 40Ar/39Ar age, interpreted as the gold metallogenic epoch of the Lijiapuzi deposit in NE China, is reported in this paper. The ore body of this deposit is hosted in the marbles and schists of the Paleoproterozoic Dashiqiao Formation and exhibits parallel development to the foliation of the country rocks. Coexisting auriferous pyrite and tremolite can be observed both in the field and under a microscope, revealing the presence of hydrothermal activity in the deposit. The δ34S composition of the auriferous pyrite varies from +8‰ to +12.3‰, indicating a sedimentary origin. The auriferous pyrite and host marble have similar Pb isotopic ratios, indicating the contribution of Paleoproterozoic sediments to gold mineralization. Furthermore, in situ S and trace element analyses of the auriferous pyrite reveal that the main gold mineralization stage was Py2, which coexists with radial tremolite. 40Ar/39Ar dating of these tremolite samples yields a plateau age of ~1851.23 Ma, with similar isochronal and inverse isochronal ages. The Paleoproterozoic gold metallogenesis, together with the contemporary Pb-Zn, boron, graphite, and magnetite mineralization, constitute an important mineralogenetic series during the evolution of the Jiao-Liao-Ji orogeny in the Liaodong Peninsula. [ABSTRACT FROM AUTHOR]

With the increasingly demanding requirement of environmental protection in China, the proportion of non-cyanide gold extraction in the gold metallurgy industry is increasing. This paper summarizes the types, performance, and gold leaching efficiency of novel environment-friendly gold extraction agents emerging in recent years in China, and focuses on the analysis and discussion of the synthesis and gold leaching mechanism of these gold extraction agents. It is suggested that further optimization of the synthesis process of the novel environment-friendly gold extraction agents, the research on the gold leaching mechanism, and continuous enhancement of its adaptability to different types of gold ores, are the key research directions of the future popularization and application of this kind of gold extraction agents, in order to provide references for the realization of "green, environmentally friendly and safe gold metallurgy". [ABSTRACT FROM AUTHOR]

The Zhashui-Shanyang ore cluster area is one of the most important gold polymetallic ones in northwestern China. The Qinglingou gold deposit is a newly discovered small-scale deposit in the Zhashui-Shanyang area. Gold mineralization closely related to acid intrusive rocks has been found for the first time in this area. In this paper, the geochronology, whole-rock geochemistry, and isotope signature of the granite porphyries in the deposit are studied. They are characterized by variable medium SiO2 (67.22–71.72 wt.%), high K2O + Na2O contents (6.54–10.34 wt.%), and variable Al2O3 (14.47–15.10 wt.%) values. The A/CNK ratios range from 0.90 to 1.23, and the A/NK ratios vary from 1.14 to 1.48. These rocks also contain biotite and amphiboles and are similar to peraluminous and high-K calc-alkaline I-type granites. The Qinglingou granite porphyries show relative enrichment of Rb, Th, and K, and depletion of Nb, Ta, P, Ti, and other high field strength elements. These porphyries are enriched in light rare earth elements relative to heavy rare earth elements with weak negative Eu anomalies (δEu = 0.63–0.89), which is interpreted to be the best age of crystallization of the Qinglingou porphyries. LA–ICPMS zircon U–Pb dating yields an age of 211 ± 1.2 Ma (n = 16, MSWD = 0.39). The close spatial relationship between the ore bodies and granite porphyry dikes indicates that this age may represent the metallogenic age in this area. The zircons have 176Hf/177Hf ratios ranging from 0.282625 to 0.282702, the εHf(t) values are near 0 and the two-stage zircon Hf model ages range from 1121 to 1296 Ma. These data indicate that the Qinglingou granite porphyries were derived from the interplay between mantle- and crustal-derived magmas. We therefore propose that there is potential gold in carbonate rocks at the periphery of porphyry-skarn copper-molybdenum deposits. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation of the incorporation of Au within pyritic ore from the Qiucun epithermal Au deposit, China. The new data provide insights into the mode of occurrence of Au during fluid-rock interactions within epithermal systems. The distribution and mode of occurrence of Au within arsenian pyrite were investigated using a chemical and structural characterization-based approach combining laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analysis, megapixel synchrotron X‑ray fluorescence analysis (MSXRF), and atom probe tomography (APT). The resulting data indicate that invisible Au is present at elevated concentrations in the form of a homogeneous solid solution within As-rich pyrite domains, which yields Au concentrations that positively correlate with As. Arsenic-induced lattice defects, such as stacking faults and the expansion of the pyrite unit cell, provide evidence of the effect of As on the incorporation of Au into pyrite. The nucleation and crystallization of electrum preferentially occurred at the fluid-pyrite reaction interface or along fractures and grain boundaries within the pre-existing pyrite. This study indicates that changes in physicochemical conditions (e.g., temperature, pH, and sulfur fugacity) during fluid-pyrite interactions are key controls on the development of nanometer- or micrometer-scale clusters of gold. The systematic compositional and textural observations documented in this study provide new insights into the mechanisms responsible for the different modes of occurrence of Au (ionic vs. particulate) and enable us to further understand the processes involved in the formation of Au mineralization. [ABSTRACT FROM AUTHOR]

Purpose: Zaozigou gold mine is located in the Qinghai-Tibet Plateau, and it is one of the largest gold (Au) mines in China. Agricultural soil pollution of toxic trace elements (TTEs) in Au mining area has become an increasingly common issue and potentially harms the environment and human health. In this paper, 78 samples were collected from a typical Au mining area to evaluate pollution degree of TTEs in the soils and assess related human health risk. Materials and methods: In this study, a total of 78 samples including 36 agricultural soil, 21 sediment, and 21 river samples were collected from the Au mining area. The soil chemical properties of soil samples were analysed. The geo-accumulation (Igeo), contamination factor (CF), and pollution loading index (PLI) were used to analyse the degree of contamination by TTEs. In addition, potential ecological and health risks to local residents via different three exposure routes were revealed using potential ecological risk index and US-EPA health risk assessment models. Pearson correlations between soil chemical properties and toxic elements concentration were calculated. Results and discussion: Results showed that the mean concentrations of As, Cd, Zn, Pb, Cr, and Hg in soils were 27.02, 4.22, 1.57, 1.46, 1.17, and 4.88 times higher than the background values, respectively. The Igeo index and CF values indicated that As pollution was the most severe and Hg and Cd pollution was moderate. Additionally, PLI indicated that soil As and Hg posed extremely high risks. The average potential ecological risk value of all TTEs was 602.34, and As had a higher contribution rate than the other elements, suggesting that the study area was under very high risk, mainly posed by soil As. The hazard index values for Pb, Cr, Cd, Hg, and Zn were below safe value of 1. However, the hazard index values of As for local adults and children were 1.66 and 10.25, respectively. Meanwhile, As presented the unacceptable carcinogenic risks for local residents. The presence of As was related to mining activities, based on the Pearson correlation (between soil chemical properties and TTE contents) and As levels in rivers and sediments near the mining area. Conclusions: As pollution from Au mining activities has posed potential ecological risks to the ecosystem and caused human health risk in the Au mining area. Therefore, more efficient policies to control As contamination in the soils should be implemented as soon as possible. [ABSTRACT FROM AUTHOR]

Recent discoveries in north-west China and the Central Asian steppes have shed new light on the study of power display and material connections amongst nomadic groups during the development of gold-making technology in Iron Age Eurasia. Bringing together material science and archaeological approaches, this paper presents an interdisciplinary study of serially produced gold artefacts recovered from the elite burials of north-west China, to gain a better understanding of the inventive nature of early gold-making industry. In particular, we find that the technology used to craft the gold appliqués found in the Xigou cemetery (3rd-2nd centuries BCE) in north-west China attested to the use of moulds or matrices for serial production, closely linked to technological practice of the central Asians steppes. We consider the spread of the peculiar technique and iconography as a tangible way to examine technology transfer and cultural interactions. The contextual analysis reveals that the mould-pressing technique, the animal-style gold artefacts, and the burial practice of using prestigious gold as body adornment constitute a shared set of material expressions of the status and power of nomadic elites in north-west China, Kazakhstan and southern Siberia. Technological practice, in turn, opens up new research avenues in the field, recalibrating our recognition and understanding the active involvement of material objects in human life and culture. [ABSTRACT FROM AUTHOR]

This paper seeks to identify macroscopic metallogenic mechanisms of various mineral deposits by studying microscopic typomorphic characteristics of typical minerals associated with the deposits and to reveal the mechanism of lattice gold in detail by studying both physical and chemical characteristics of quartz from representative gold deposits in the North China Platform. As part of their extensive research, the authors examine the relationship between trace elements with wall rock, the ore-forming media, and gold immigration of various types of gold deposits, including their salinity, type, temperature. These are key factors to revealing the mineralization mechanism, and indicators for mineral prospecting, exploration, mining, and metallurgical technology. In order to address the questions posed, the following methods were used: field investigations of geology and sampling of the representative gold deposits, physical study and chemical analysis of quartz including, but not limited to, fluid inclusions as well as their compositions and trace elements in quartz, the unit cell parameters, electron paramagnetic resonance spectrum (EPR), and infrared spectroscopic analysis (ISA). As a result of this study, the authors observe the following key findings: unit cell parameters of quartz vary with their contents of foreign elements including gold, paragenetic stage, wall rock type, and other factors; the higher the forming temperature and the lower the gold content in quartz, the smaller the unit cell parameters, and vice versa. Additionally, the EPR absorption lines resulted from the O–Al defect center. The density of these types of hole centers increases and the EPR signal strengthens when the temperature decreases. Based on the findings, the authors conclude that lattice gold exists in quartz. Gold, in the form of Au+ and/or Au3+, entering quartz and producing an electron–hole center, namely, the O-Au hole center, makes the center produce spin resonance absorption and results in the EPR absorption peak #I. Both unit cell parameters and EPR of quartz can potentially be used in mineral prospecting, relative ore-forming temperature determination, and grade control during mining. [ABSTRACT FROM AUTHOR]

As the most important gold producer in China, the Northwest Jiaodong Peninsula is famous for its large gold deposits. In recent years, the discovery of gold mineralization has reached a depth of 4 000 m below the surface in this region. It has attracted significant interest from explorers about the prospecting potential at greater depths. Besides, the current deep drilling shows that the prospecting effect in the west portion is better than the region to the east. Does it imply that there is a difference in prospecting potential between the east and the west? This paper seeks to address the issue through fission track thermochronology on apatite and zircon to reveal the temperature-time evolution relationship of rock mass and to inverts their thermal evolution history. In addition, this study analyzes the transformation of ore deposits after mineralization, quantitatively calculates the uplift-erosion rate of rock mass, and summarizes the preservation law of ore deposits. Based on the thermal history simulation of the apatite fission track, our results show that the Guocheng gold belt has experienced three stages of thermal evolution: 108–74, 74–27, and 27–0 Ma. The uplift and cooling processes of the three-stage tectonic uplift events are the results of multi-stage Pacific plate accretion. The calculated total denudation depth of the gold deposit in the Guocheng gold belt from Cretaceous to the present is about 3.4–5.3 km. The metallogenic depth of the ore body in the gold belt is 5.6–8.0 km, which indicates that the ore body in the Guocheng gold belt has suffered a significant degree of denudation. It is speculated that the location with less denudation in the southwest has greater prospecting potential. Our results quantitatively identify the uplift and denudation of the deposit after mineralization, which provides a new theoretical reference for regional mineralization, deep prospecting and exploration. [ABSTRACT FROM AUTHOR]

The preparation technology of micron spherical metal powder has become a common problem in the fields of chip, medical diagnosis, and 3D-printing. In this paper, micron spherical gold powder was prepared by hydrometallurgy process, and high-purity conductive gold ball was prepared by plasma spheroidizing method. The high-purity and highly dispersed gold powder was prepared with the self-made Au-99. 999% as raw material, hydrazine hydrate as reducing agent and PVP as diluent, and the reduction potential was controlled at 1 692 ~ 1 002 mV, 5N micron conductive gold spheres for semiconductor chips are obtained by gas flow crushing and plasma spheroidizing. At present, this method has realized industrialized production of 10 kg, preliminarily solved the problem that the conductive gold ball for domestic chip packaging was monopolized by other countries, and made an important contribution to improving China's chip R & D industry chain, especially the research and development of electronic grade gold raw materials. [ABSTRACT FROM AUTHOR]

Exploration of deep mineralization, particularly where the mineralization of interest is covered by a conductive overburden, is still a challenge for the conventional transient electromagnetic (TEM) method, which measures TEM response using induction coils as the sensor. However, sensors such as fluxgate and superconductive quantum interfere device (SQUID) magnetometers can measure the B-field directly, which can provide more reliable deep information for mineralization exploration. In this paper, we report on the research and development of our newly developed high-temperature superconductor (HTS) SQUID magnetometer, which is cooled by liquid nitrogen at 77 K, and its application in TEM measurement for deep exploration in a gold deposit in China. This improved SQUID magnetometer version has a good performance with noise (60 fT/ Hz ), slew rate (0.8 mT/S), dynamic range (100 dB), sensitivity (6.25 mV/nT), and bandwidth (DC-20 kHz). To find deep and peripheral ore in the Baiyun gold deposit located in Liaoning Province, NE China, both the SQUID magnetometer and induction coil were used for TEM data acquisition. Results show that TEM can detect the distribution of local strata and the faults contained within them. Results also indicate that the SQUID magnetometer has superior response performance for response over geological targets with slower decay time when compared to the induction coil signals. The SQUID magnetometer is more sensitive at observing the induced-polarization effect which is closely related to the ore-controlling faults. [ABSTRACT FROM AUTHOR]

The migration, accumulation and dispersion of elements caused by tectonic dynamics have always been a focus of attention, and become the basis of tectono‐geochemistry. However, the effects of faulting, especially strike‐slip faulting, on the adjustment of geochemical element distribution, are still not clear. In this paper, we select the West Junggar Orogenic Belt (WJOB), NW China, as a case study to test the migration behavior of elements under tectonic dynamics. The WJOB is dominated by NE‐trending large‐scale sinistral strike‐slip faults such as the Darabut Fault, the Mayile Fault, and the Baerluke Fault, which formed during the intracontinental adjustment under N–S compression during ocean‐continental conversion in the Late Paleozoic. Geochemical maps of 13 elements, Al, W, Sn, Mo, Cu, Pb, Zn, As, Sb, Hg, Fe, Ni, and Au, are analyzed for the effects of faulting and folding on element distribution at the regional scale. The results show that the element distribution in the WJOB is controlled mainly by two mechanisms during tectonic deformation: first is the material transporting mechanism, where the movement of geological units is consistent with the direction of tectonic movement; second is the diffusion mechanism, especially by tectonic pressure dissolution driven by tectonic dynamics, where the migration of elements is approximately perpendicular or opposite to the direction of tectonic movement. We conclude that the adjustment of element distributions has been determined by the combined actions of transporting and diffusion mechanisms, and that the diffusion mechanism plays an important role in the formation of geochemical Au blocks in the WJOB. [ABSTRACT FROM AUTHOR]

Previously, the multi‐channel transient electromagnetic (MTEM) system has been successfully developed and applied to hydrocarbon reservoirs exploration on land and offshore environments in France. In order to explore the mineral resources buried at the depths up to 2,000 m in China, we developed a new MTEM system. In this paper, we present the components of the system, methods, principles, the parameters of the system, and the data interpretation method. To validate the effectiveness of the methodology and the developed system, we carried out an MTEM survey to locate the controlling faults of a gold deposit in the east of China. The survey contains 30 receivers distributed over 12‐km survey. By comparing the MTEM interpretation results with the known geological background, we find that MTEM methods can provide a good estimation of the ore‐controlling faults and this method could be a potential tool for the future deep mineral exploration. [ABSTRACT FROM AUTHOR]

The Jiapigou gold ore belt is located in the northeastern corner of the wedge‐shaped North China Craton and is hosted by Neoarchean basement gneiss and amphibolite, along with late Palaeozoic and Mesozoic granitoids. In this paper, whole‐rock major and trace element geochemistry together with zircon U–Pb ages and Lu–Hf isotope compositions are reported for Late Permian to Triassic igneous rocks from the gold belt. The dominant population of zircons in all these rocks shows oscillatory growth zoning in CL images, and relatively high Th/U ratios (0.10–5.23) that are indicative of a magmatic origin. Zircon U–Pb data indicate that the igneous rocks formed during two major phases: ca. 252 Ma and ca. 230–213 Ma. Geochemically, the Late Permian (ca. 252 Ma) diorites are high‐K calc‐alkaline in composition and low total Fe2O3, MgO, and CaO contents, and represented by enrichment in LILEs relative to HFSEs and HREEs, all of which are indicative of a postcollision high‐K calc‐alkaline granite affinity. In contrast, the Late Triassic (ca. 230–213 Ma) igneous rocks are mainly quartz syenite porphyries, felsites, and granodiorites, and are variable medium‐ to high‐K calc‐alkaline series and exhibit a negative Eu anomaly with A‐type affinities, indicating an extensional environment. In addition, in situ Hf isotopic analyses of zircons from four dated samples reveal that they have εHf(t) values of −3.0 to +2.2, with two‐stage model (TDM2) ages range from 964 to 1,210 Ma, indicating that they probably originated from the partial melting of a dominantly Mesoproterozoic to Neoproterozoic crustal source. On the basis of the geochemical data and regional geological investigations, we further propose that the Jiapigou gold ore belt in the Late Permian was formed in a postcollisional tectonic setting, whereas an extensional tectonic setting in the Late Triassic that caused lithospheric thinning during a postorogenic event. [ABSTRACT FROM AUTHOR]

Data-driven prospectivity modeling based on deep learning, particularly supervised learning, has demonstrated outstanding performance for mineral exploration targeting in the past years, thanks to its powerful feature learning ability. However, this approach necessitates a substantial amount of large, high-quality labeled training data, and the scarcity of known mineral deposits poses significant challenges in constructing a high-performance mineral prospectivity prediction model. Self-supervised contrastive learning can alleviate this problem by exploiting large amounts of readily available unlabeled data. In this study, we utilized geochemical element data from the Malanyu district to train a self-supervised contrastive learning model. This model was then employed to predict gold mineral prospectivity, and its accuracy was compared with supervised learning method. The results show that the self-supervised contrastive learning model has higher performance in prospectivity prediction than the supervised learning model and its recognition accuracy reaches 100.00%, which is 7.41% higher than that of the supervised learning model ResNet50 and 14.81% higher than that of the supervised learning model MobileNetV2. At the same time, the prediction results of gold prospecting have a strong consistency with the known gold deposits in this district. This study demonstrates the feasibility of applying the self-supervised comparative learning model to the prediction of gold prospects, and it is of great significance to realize intelligent prediction of mineral resources. Article Highlights: A self-supervised contrastive learning model is proposed for predicting gold prospectivity. The model can learn valuable feature representations from a large amount of readily available unlabeled geochemical data. Compared to the supervised learning method, the proposed model not only reduces reliance on the number of known deposits but also achieves higher accuracy. [ABSTRACT FROM AUTHOR]

This paper focuses on the area around the Changgou gold mine within the North Hanyin area of the South Qinling Mountains, China. We combine new large‐scale field geological, tectonic, and lithofacies data with the results of previous research and present new information on the geological characteristics of mineralization within this region. These data indicate that the Changgou gold mine is a brittle–ductile shear zone associated gold deposit and that the key controls on the formation of the deposit can be used to identify areas in this region that are favourable for future exploration. The key control on the spatial distribution of mineralization within the Changgou gold mine area is the location of the DSZ3 brittle–ductile shear zone, with secondary faults and fractures controlling the specific locations of gold orebodies. The structural deformation is dominated by the development of an S2 foliation that strikes 290–350° (predominantly inclination 230° and dip 30°). Gold‐bearing pyrite is preferentially aligned along the S2 foliation, and individual orebodies are preferentially located along the S2 foliation. Therefore, this foliation controlled the location of mineralization at both micro‐ and macroscopic scales. Mineralization also occurs in S2‐phase quartz veins that contain visible granular gold, whereas the S3‐phase quartz veins are generally barren and are not related to the location of gold mineralization. Fluid inclusion microthermometry indicates that gold‐bearing quartz veins homogenized at 190–260°C and have salinities (in NaCl equivalent terms) of 6–12%. All of these fluid inclusions contain gas and liquid phases dominated by CO2 and H2O, respectively, indicating that they are CO2–H2O type. The hydrothermal fluids that formed the Changgou deposit are similar to those that generate epithermal deposits (i.e., moderate‐ to low‐temperature, moderate‐ to low‐salinity, and low‐density CO2–H2O fluids). Our research into the geological characteristics of the quartz veins that formed at different times in the study area and their associations with different styles of mineralization and alteration indicates that the hydrothermal fluids associated with the S2 period of deformation were the main ore‐forming fluids associated with the Changgou gold deposit. [ABSTRACT FROM AUTHOR]

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Dayaoshan, as an important metal ore-producing area in China, is faced with the dilemma of resource depletion due to long-term exploitation. In this paper, remote sensing methods are used to circle the favorable metallogenic areas and find new ore points for Gulong. Firstly, vegetation interference was removed by using mixed pixel decomposition method with hyperplane and genetic algorithm (GA) optimization; then, altered mineral distribution information was extracted based on principal component analysis (PCA) and support vector machine (SVM) methods; thirdly, the favorable areas of gold mining in Gulong was delineated by using the ant colony algorithm (ACA) optimization SVM model to remove false altered minerals; and lastly, field surveys verified that the extracted alteration mineralization information is correct and effective. The results show that the mineral alteration extraction method proposed in this paper has certain guiding significance for metallogenic prediction by remote sensing. [ABSTRACT FROM AUTHOR]

Exploration for buried gold ores and other deeply buried ores, especially in high altitude localities, is one of the tough challenges facing the geological world today. Fast and efficient ore prospecting methods are badly needed to deal with the situation. This paper documents a test that, for the first time, uses an electrogeochemical approach to prospect ores in the alpine meadow-covered Bangzhuoma area and its periphery in Qinghai-Tibet Plateau. The results were compared with conventional soil measurements from a 2D prospection, and an ideal model of electrogeochemical anomaly formation in the area was established based on the comparison in order to provide theoretical guidance to buried ore prospecting in areas with similar conditions. The research shows that: (1) For exploration of deeply-buried mineral deposits, an electrogeochemical approach is better than soil measurements in terms of correspondence between element content values and anomaly forms and spatial distribution of known deposits in sections. Anomalies of high to low temperature element associations (Bi-Mo; Au-Ag-As-Bi and Au-Ag) and clear zonation were also observed along vertical vein runs in the sections. Based on integration of the observation with geological characteristics of the sections, we propose to use Au, Ag and As as the electrogeochemical indicators and Bi and Mo as the electrogeochemical tracing elements to guide further analysis. (2) Judging from element statistics and the scale, intensity, and range of anomalies in plan maps, we found that an electrogeochemical approach is less affected by topography and secondary actions. The plan maps also show that elemental differentiation coefficients of the study area are in an ascending order of Ag (0.67) < Mo (0.85) < Bi (0.97) < Au (1.51) < As (2.35), better representing the element distribution in the area and yielding more striking and concentrated anomalies for known deposits than that of the soil measurements. Apart from that, electrogeochemical anomalies were observed in the south of lines 002 and 003 and the central of lines 008 and 009. We suggest the existence of deeply-buried mineral deposits based on analyses of element combinations and gold grade variations in samples taken from exploratory trenches in the area. (3) A three-stage (referring to the ore body dissolution, the mineralogenetic particle migration, and the mineralogenetic particle unloading) electrogeochemical ideal model was established for the study area, which takes into account moderate rainfall, high altitude, low air pressure, well-developed vegetation and roots, and an Upper Triassic Nieru Formation carbonaceous sandy slate as overburden. [ABSTRACT FROM AUTHOR]

Seven pieces of gold foils for surface decoration of the lacquerware were excavated in the late Western Han Dynasty tomb in the area of the Jin Yang (晋阳) Ancient City site in Taiyuan (太原), Shanxi (山西), China. These gold foils portray images of the carriage, the leopard, the tigers, the ox, and the dancer with fluttering sleeves, etc., with black lines outlining the contours and red paint depicting vivid patterns. The study used Stereo Microscopes, Metallurgical Microscopy, Environmental Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDS), and Laser Raman Spectroscopy (LRS) to analyse the thickness of the gold foils, the alloy composition, the composition of the paint and other surface attachments, and investigate the manufacturing process. As the results show, the thickness of the gold foils is about 26 μm. The composition is a gold-silver alloy with about 96% Au/(Au + Ag) (surface) and 98% Au/(Au + Ag) (cross-section). The metallurgical observation shows that the gold foils underwent heating and forging. The black lines on the front side are Chinese ink lines, with cracking and peeling phenomenon, and parallel polishing lines can be seen at the peeling places, while no polishing lines are observed on the back side. Some red paint made of cinnabar is above the black lines, and the binder is organic. Some lacquer residues are found on the back. According to the results of the study, the manufacturing process of the gold foils applied on the lacquerware is as follows: the gold foils are obtained by heating and forging, the front sides of the gold foils are polished, the shapes are carved out, and the gold foils are pasted on the lacquerware when the lacquerware's surface is not yet dry. The gold foils are painted with black Chinese ink and red cinnabar pigment. The study's results offer important references for understanding the manufacturing craft of the gold foils applied on the lacquerware in the late Western Han Dynasty of China and guide the conservation of the lacquerware decorated with painted gold foils. [ABSTRACT FROM AUTHOR]

Delineating the process of hydrothermal alteration is crucial for effectively enhancing exploration strategies and better understanding the gold mineralization process. Rutile, with its capacity to accommodate a wide range of trace elements including high-field-strength elements and base metals, serves as a reliable fluid tracer in ore systems. As one of the most significant gold ore concentrations globally, Jiaodong boasts a gold reserve exceeding 5500 t. The Xincheng gold deposit is a world-class high-grade mine, boasting a proven gold reserve exceeding 200 t, and stands as one of the largest altered-type gold deposits in the vast gold province of the Jiaodong Peninsula, Eastern China. In this study, rutile (Rt1,2,3) was identified in the K-feldspar alteration, sericitization, and pyrite–sericite–quartz alteration stages of the Xincheng gold deposit in Jiaodong based on petrographic characteristics. Rt1 coexists with hydrothermal K-feldspar and quartz, while Rt2 coexists with minerals such as sericite, quartz, muscovite, and pyrite. Rt3 is widely distributed in hydrothermal veins and is primarily associated with minerals including quartz, pyrite, chalcopyrite, and sericite. Raman spectroscopy, EPMA, and LA-ICP-MS analysis were conducted to investigate the characteristics and evolution of altered hydrothermal fluids. This study indicates that the Zr vs. W and Nb/V vs. W diagrams suggest that Rt1 is of magmatic–hydrothermal origin, while Rt2 and Rt3 are of metamorphic–hydrothermal origin. Notably, the W content in Rt2 and Rt3 is significantly higher than in Rt1 (<100 ppm), suggesting a close relationship between the W content in rutile and mineralization. The three types of rutile exhibit significantly different concentrations of trace elements such as W, V, Nb, Zr, Sn, and Fe, displaying distinct bright spots and elemental zoning characteristics in backscattered electron images and surface scans. These features arise from the isomorphic substitution of Ti4+. While Rt1 exhibits no significant element exchange with the hydrothermal fluids, Rt2 and Rt3 show a stronger substitution of W, Nb, V, and Fe, indicating a gradual enrichment of F and Cl in the fluids. This process activates and transports these elements into the fluids, leading to their continuous accumulation within the system. From Rt1 to Rt3, the increasing concentrations of Fe and W, along with the negative Eu anomaly, suggest a decrease in fluid temperature and oxygen fugacity during the alteration and mineralization process. The gradual increase in the contents of REEs and high-field-strength elements such as W, V, Nb, and Sn indicates that the hydrothermal fluids are enriched in F and Cl, exhibiting weak acidity. The nature of the fluids during hydrothermal alteration is closely related to the composition of rutile, making it a promising tool for studying hydrothermal alteration and related mineralization processes. [ABSTRACT FROM AUTHOR]

The Yueguang gold deposit is located in Fengjia, Xinhua County, Hunan Province, South China. It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt, west of the Baimashan granitic batholith. In order to discern the characteristics of the ore-forming fluids, the underlying mineralization processes, and establish a foundation for the origin of the Yueguang gold deposit fluid inclusion microthermometry, as well as quartz hydrogen and oxygen isotope analysis, have been carried out on samples obtained from various stages of mineralization. The hydrothermal mineralization stages within the Yueguang gold deposit can be categorized into three stages: (i) the barren, pre-ore quartz-pyrite stage (Stage I), the quartz-pyrite-gold stage (Stage II), and the post-ore quartz-carbonate stage (Stage III), with the second stage being the main mineralization stage. The fluid inclusions identified in samples from the main mineralization stage can predominantly be described with the NaCl–H2O and CO2–NaCl–H2O systems. These inclusions display homogenization temperatures ranging from 158.8 to 334.9 °C, and the fluid salinity ranges from 0.3% to 4.0% (wt.% NaCl equiv.). Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO2, CH4, and N2. Isotopic analysis indicates δ18O fluid values ranging from 3.95 to 6.7 ‰ and δDH2O values ranging from − 71.9 to − 55.7 ‰. These results indicate that the ore-forming fluid of the Yueguang gold deposit belongs to metamorphic hydrothermal fluids of middle-low temperature and low salinity. In the process of ore formation, gold is transported in the form of Au (HS)2− complexes, with gold deposition being driven by fluid immiscibility. Therefore, the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrothermal fluid. It may become a new target for gold exploration in the Baimashan region, central Hunan Province. [ABSTRACT FROM AUTHOR]

This paper examines the dynamic relationships between gold and stock markets in China. Using daily gold and stock indexes data, we estimated the DCC-GARCH model for the five bear markets since 31 October 2002, and simultaneously used different segments of China's stock markets for analysis. Our main objective was to examine the time-varying correlations between gold and stock and to check the effectiveness of gold as a hedge or a safe haven for stocks. Results showed that: (1) the dynamic conditional correlations switched between positive and negative values over the periods under study; (2) due to the increasing investment demand of gold, the hedging effect of gold on China's stock market has strengthened remarkably. Gold acts as a safe haven for only the latest two of the five bear markets analyzed (12 June 2015-26 August 2015 and 22 December 2015-29 February 2016); and (3) for non-bear markets, gold does not offer good risk hedging. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pianyanzi area in western Sichuan hosts a rare sellaite-bearing orogenic gold deposit. • Gold is mostly present as visible native gold formed in two stages. • Gold precipitation was forced by interaction between auriferous fluids and wall rocks. • Metasomatized mantle lithosphere served a potential source of ore fluids. The Pianyanzi gold deposit is situated at the western margin of the Yangtze Craton, and represents a rare sellaite-bearing orogenic gold deposit. This deposit belongs to the Dauduhe gold belt of southwestern China and remains poorly documented. In this paper we present first petrographic and in-situ geochemistrical and sulfur isotope data from pyrite as well as results of multielement mapping. The deposit is dominated by native gold (average gold fineness = 980.8) filling fractures in minerals (e.g., pyrite, quartz, sellaite and hematite) or also emplaced along the contact interface between mineral grains. Pyrite is the most abundant sulfide mineral of this deposit. We identified five generations of pyrite: Py1, Py2a, Py2b, Py3, and Py4. Gold occurs in sellaite- and hematite-bearing mineral assemblages formed simultaneous with the formation of Py2a&b and Py4, respectively. Py1 formed in the Au-poor ore stage, while Py3 formed during the late galena-dominated sulfide stage. All generations of pyrite exhibit low concentrations of gold with an average value of less than 2 ppm. Py2a&b possess distinctive textures and chemical zonation, with trace elements displaying greater variations compared to Py1, Py3 and Py4. The δ34S values vary from −0.52 ‰ to 7.08 ‰, which is consistent with those of orogenic deposits of the Daduhe gold belt. The deep metasomatized mantle lithosphere acted as a potential source of ore fluids. We conclude that the co-precipitation of native gold and sellaite was triggered by the interaction between auriferous fluids and dolomite. [ABSTRACT FROM AUTHOR]

Gold mineralization in the Jiaojia gold belt was formed in a structurally- dominant hydrothermal mineral system showing a close spatial association with the Jiaojia detachment fault. This study delves into the Jiaojia gold belt from the perspective of coupled spatial association and ore-forming processes by employing spatial analysis of three-dimensional (3D) models, 3D ore-forming numerical modeling, and 3D prospectivity modeling using machine learning techniques (random forest (RF) and multilayer perceptron (MLP)). The overarching goal is to gain insight into the structural-hydrothermal gold system and pinpoint potential areas of deep-seated gold deposits for future exploration endeavors. The spatial analysis of ore-controlling faults uncovers a close correlation between gold enrichment and specific fault geometrical attributes, including a dip angle ranging from 20° to 40°, minimal variations in dip angle (less than 5°), and convex topographical features. These attributes likely stem from the influence of fault morphology on the flow and pooling of fluids. In conjunction with this, 3D ore-forming numerical modeling of structural deformation and fluid flow reveals that gold mineralization is intertwined with moderate volumetric strain and shear strain of rock and fluid divergence. This interaction seems particularly pronounced in areas characterized by channel-like or gentle features. Consequently, it is plausible that gold distribution in the Jiaojia region is the outcome of a comprehensive coupling process involving strain localization, rock deformation, fluid flow, heat transfer and/or interaction. The deep gold prospectivity models of RF and MLP for the Jiaojia district jointly using the predictive variables of fault geometry features and ore-forming simulation data (volume strain, shear strain, temperature variation, and fluid flux) exhibit higher AUC (area under the curve) values compared to models employing individual predictor variable datasets. This improvement underscores their enhanced predictive capability. The prospectivity results thus were used for identifying gold potential within the Jiaojia region, where five promising gold targets at depth were ultimately determined. [ABSTRACT FROM AUTHOR]

The Jiaodong gold province is one of the most important gold fields globally and the largest in China. The Denggezhuang gold deposit is situated in the eastern portion of the Muping metallogenic belt, within the Jiaodong gold province. Despite many recent investigations, detailed mineralogical studies, particularly on auriferous minerals such as pyrite, are lacking. Therefore, further constraints on the occurrence mode and source of gold are necessary for this deposit. This study employed in situ laser ablation (multi-collector) inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) trace element and sulfur-lead isotopic analyses on pyrite at different stages. The aim was to reveal the occurrence status of various trace elements within Denggezhuang pyrite and to trace the complete evolution process of multi-stage fluids at Denggezhuang, elucidating the sources of gold mineralization. Four generations of pyrite in chronological order, Py-1, Py-2a, Py-2b, and Py-3, were identified via petrographic and backscattered electron (BSE) image analyses. Using in situ LA-MC-ICP-MS, we found that Co and Ni are most abundant in Py-1, while Py-2b is rich in As, Au, Ag, Pb, and Zn, reflecting the evolution of the mineralizing fluids in different mineralization stages. Py-2b contains a significant amount of invisible lattice gold, which migrates and precipitates within fluids rich in As. The in situ LA-MC-ICP-MS S-Pb isotopic analysis of pyrite indicates a relatively consistent source of ore-forming materials across different stages. Additionally, the S-Pb isotope characteristics resemble those of widely distributed coeval mafic dikes. Therefore, we propose that a water-rich, fertile, and deep-seated mafic magmatic system might have provided fluids, materials, and heat for mineralization. [ABSTRACT FROM AUTHOR]

We present in situ LA-ICP-MS U-Pb dating of xenotime and monazite in assemblages with native gold and Au (Ag) tellurides from the Xiaoqinling lode gold district in central China. Composite xenotime and monazite grains formed through coupled dissolution-reprecipitation reactions reveal two discrete gold mineralization events. The first gold mineralization event, recorded by monazite (158.6 ± 3.3 Ma, Tera-Wasserburg lower intercept age) and xenotime cores (157.11 ± 0.83 Ma, weighted mean 206Pb/238U age), is characterized by the mineral assemblage of lingbaoite (AgTe3)-sylvanite ([Au,Ag]2Te4)-stützite (Ag5–xTe3)/native tellurium-sylvanite-stützite. The second gold mineralization event, recorded in the rims of xenotime (135.46 ± 0.93 Ma, weighted mean 206Pb/238U age), is characterized by the mineral assemblage of native gold-calaverite (AuTe2)-petzite (AuAg3Te2)-tellurobismuthite (Bi2Te3). Our study implies that the large-scale Jurassic mineralization event in eastern China, related to flat subduction of the paleo-Pacific plate beneath the eastern China continent, also caused widespread gold mineralization in the Qinling-Dabie Orogen, in addition to production of its world-class porphyry Mo deposits. The fact that only a few Jurassic gold mineralization ages have been reported before, may be due to the lack of suitable geochronometers to record the earlier Jurassic hydrothermal processes, which have been overprinted by the better-recognized Early Cretaceous gold mineralization event. This study also presents a rare example of xenotime compositional alterations and resetting of U-Pb ages induced by low to moderate salinity carbono-aqueous fluids at low temperatures. The textural relationships between gold minerals in contact with such composite xenotime crystals demonstrate that they could have precipitated before, coeval with, or after the dated domains. Since low to moderate salinity carbonoaqueous fluids are commonly involved in the formation of lode gold deposits, it is crucial to examine xenotime textures and recognize potential alteration textures before carrying out isotopic dating of xenotime collected from these deposits. Without prior compositional and textural characterization, attempts to date such composite crystals could yield mixed dates and meaningless ages. [ABSTRACT FROM AUTHOR]

From integrated textural and compositional studies of auriferous and barren pyrite/marcasite in the epithermal Axi gold deposit, China, we have identified a relationship between multiple gold mineralizing events, mafic magma recharge, and fluid-rock reactions. Three generations of pyrite (Py1–3) and four generations of marcasite (Mar1–4) record episodic gold mineralizing events, followed by silver-copper-lead-zinc-cadmium enrichment. The gold mineralizing events are recorded by high concentrations of subnanometer-sized gold in Py1, Py3, and Mar3 (max. = 147, 129, and 34 ppm, med. = 39, 34, and 12 ppm). Based on previous Re-Os age determinations of pyrite and U-Pb zircon ages of the andesitic wallrock, these gold events slightly postdate pulsed mafic magma recharge and represent the incursion of Au-As-S-rich magmatic volatiles into circulating meteoric water. Silver-Cu-Pb-Zn-Cd enrichment in Py2, Mar2, and Mar4 are consistent with quiescent degassing and gradual Ag-Cu-Pb-Zn-Cd enrichment in an evolved felsic magma. Barren Mar1 records the dominance of meteoric water and a limited magmatic fluid contribution. High-Co-Ni-V-Cr-Ti contents in porous cores of Py1 and Mar2 are attributed to wall rock alteration and dissolution-reprecipitation. The results provide convincing evidence that the metal budget (especially for Au, Ag, Cu, Pb, Zn, Sb) of the hydrothermal fluids and sulfides in epithermal systems are controlled by the influx of magmatic fluids and associated magma, whereas the enrichment of certain fluid-immobile elements, such as Co, Ni, V, Cr, and Ti, is caused in part by fluid-rock interaction. [ABSTRACT FROM AUTHOR]

The Zhen'an-Xunyang Basin is a late Paleozoic rifted basin with a series of Au-Hg-Sb deposits that have been found, mostly along the Nanyangshan fault. Recently discovered large- and medium-sized gold deposits such as the Xiaohe and Wangzhuang deposits exhibit typical characteristics of Carlin-type gold deposits. Therefore, it is imperative to select a typical deposit for an in-depth study of its metallogenic mechanism to support future prospecting efforts targeting the Carlin-type gold deposits within the area. Based on detailed field investigation and microphotographic observation, four ore-forming stages are identified: I, low-sulfide quartz stage, characterized by euhedral, subhedral pyrite, and fine veins of quartz injected parallel to the strata; II, arsenopyrite–arsenian pyrite–quartz stage, the main mineralization stage characterized by strongly silicified zones of reticulated quartz, disseminated arsenopyrite, fine-grained pyrite; III, low-sulfide quartz stage, characterized by large quartz veins cutting through the ore body or fine veins of quartz; Ⅳ, carbonate–quartz stage, characterized by the appearance of a large number of calcite veins. In situ analysis of trace elements and S isotopes of typical metal sulfides was carried out. The results show significant variations in the trace element compositions of metal sulfides in different stages, among which the main mineralization stage differs notably from those of the Au- and As-low surrounding strata. In situ S isotope analysis reveals δ34S values ranging from 15.78‰ to 28.71‰ for stage I metal sulfides, 5.52‰ to 11.22‰ for stage II, and 0.3‰ to 5.25‰ for stage III, respectively, revealing a gradual decrease in S isotopic values from the pre-mineralization stage to post-mineralization stage, similar to those observed in the Xiaohe gold deposit. These features indicate a distinct injection of relatively low 34S hydrothermal fluids during the mineralization process. The element anomalies of the 1:50,000 stream sediment in the region revealed ore-forming element zonation changing in W→Au (W)→Hg, Sb (Au) anomalies from west to east, manifested by the discovery of tungsten, gold, and mercury–antimony deposits in the area. Moreover, conspicuous Cr-Ni-Ti-Co-Mo anomalies were observed on the western side of the Wangzhuang and Xiaohe gold deposits, indicating a potential concealed pluton related to these deposits. These lines of evidence point to a magmatic–hydrothermal origin for the Carlin-type gold deposits in this area. Furthermore, hydrothermal tungsten deposits, Carlin-type gold deposits, and low-temperature hydrothermal mercury–antimony deposits in this region are probably controlled by the same magma–hydrothermal system. [ABSTRACT FROM AUTHOR]

The Nanpanjiang basin hosts the world's second-largest concentration of Carlin-type gold deposits. To decipher the origin and evolution of hydrothermal fluid, this study conducted Sm–Nd dating, in-situ trace element, and C-O-Sr isotopic analyses on three types of calcite samples from the giant Lannigou gold deposit in the Nanpanjiang basin, SW China. The type-I calcite, intergrown with Au-bearing arsenian pyrite, has an Sm–Nd isochron age of 213 ± 7 Ma (MSWD = 0.81), indicating that gold mineralization occurred in Late Triassic. The type-II calcite, which coexists with high-maturity bitumens and cut through the main-stage gold orebodies, yields an Sm–Nd age of 188 ± 14 Ma (MSWD = 0.34), representing a post-ore hydrocarbon accumulation event. The type-I and type-II calcite samples have low REE contents (5.28–51.6 ppm) and exhibit MREE-enriched and LREE-/HREE-depleted patterns. Combined with their identical C-O-Sr isotopes, we suggest that hydrothermal fluids responsible for the precipitation of type-I and type-II calcite samples were derived from a mixed metamorphic fluid and meteoric water source. In contrast, the type-III calcite samples, associated with realgar and orpiment, have distinct Mn, Sr, and As contents, REE patterns, and C-O-Sr isotopic composition from the type-I and II calcites, suggestive of different fluid sources. Based on our and previously published data, we propose that the fluid evolution, gold mineralization, and hydrocarbon accumulation in the Nanpanjiang basin are closely related to the Indosinian and Yanshanian orogenies in South China. [ABSTRACT FROM AUTHOR]

The Daliuhang gold deposit in the Qipengfu (Qixia–Penglai–Fushan) ore concentration area is a typical gold deposit of medium-low temperature hydrothermal veins. Uncertainties regarding the primary sources of ore-forming fluids, as well as whether host rocks contribute materials to the mineralization of the gold deposits in the Jiaodong Peninsula, are still subject to intense debate. Hydrogen–oxygen isotope results show that atmospheric water is involved in ore-forming fluids. According to the results of the helium–argon isotopes of pyrite, it is hypothesized that the initial fluid source was located in the oceanic crust or upper mantle lithosphere above the Early Cretaceous Paleo-Pacific Plate, as it was subducted into the eastern part of the eastern North China Craton. In situ sulfur isotope results show that high δ34S values characterize the pyrite in the main mineralization period. It is inferred that during the thinning and melting process of the lithospheric mantle, the volatile components enriched in pyrite contributed to the release of δ34S. At the same time, when the fluids ascended to the weak zones, such as fissures of ore-endowed peripheral rocks, the δ34S in the peripheral rocks were extracted, and the two processes acted together to cause high δ34S values to occur. Similarly, the lead and strontium isotopic compositions indicate a crust–mantle mixing attribute of the mineralized material source. The zircon U–Pb age of the ore-hosting granodiorite was 130.35 ± 0.55 Ma, and the Rb–Sr isochron age of the pyrite from the main mineralization period was 117.60 ± 0.10 Ma, which represents the timing of felsic magmatism and gold mineralization, respectively, with at least 10 Ma between the magmatism and mineralization. The magma gradually cooled over time after its formation, and when the granodiorite cooled down to 300 ± 50 °C, the temperature and pressure conditions were most conducive to the precipitation of gold. It is inferred that gold-rich initial mantle fluids with volatile components, rising along tectonically weak zones, such as fractures, underwent fluid phase separation in the fractured position of the granite and extracted the gold from the granodiorite, forming gold deposits. [ABSTRACT FROM AUTHOR]

• 664 suites of fault-slip data were obtained at the Katebasu Au deposit in Tianshan. • Three stages of deformation have been recognized at the deposit scale. • The deposit structural history correlates to amalgamation of the Tianshan orogen. The western Tianshan orogen is one of the world's most important gold provinces. It hosts numerous world-class gold deposits along the southern and northern margins of the Middle Tianshan. Most deposits occur within large-scale fault zones and/or ductile-brittle deformation zones that were formed during the Paleozoic evolution of the Paleo-Asian Ocean, thereby indicating a correlation between orogenic tectonics and the gold mineralization. However, the correlation is often poorly constrained and remains controversially discussed. The Katebasu gold deposit in Xinjiang, China, is located on the northern margin of Middle Tianshan and is hosted by secondary fault zones to the south of the North Nalati Fault. The main period of gold mineralization is suggested to be the Late Carboniferous, which is broadly coeval with the late Paleozoic amalgamation of the western Tianshan. Therefore, the Katebasu gold deposit provides an excellent opportunity to search for possible correlations between structural processes at a deposit scale and orogenic processes at a regional scale to better understand the tectonic controls on large-scale gold mineralization in the western Tianshan. In this paper, we report detailed structural mapping and field investigations on the fault geometries and kinematics of the Katebasu gold deposit that permit inversion of the tectonic stress field. Our structural data, combined with results of previous studies of the regional tectonics, allow us to reconstruct the structural history of the Katebasu gold deposit, to look for possible correlations with the orogenic processes in the western Tianshan and to determine their control on gold mineralization. The first stage of deformation (D 1) was top-to-the-north thrusting that was caused by a roughly N–S compression and is represented by ENE–WSW-striking thrust faults. D 1 was likely related to the closure of the South Tianshan Ocean and the resulting collision between the Tarim craton and Middle Tianshan–Yili block. The second stage of deformation (D 2) was dextral strike-slip motion along the ENE–WSW-striking faults that was caused by the WNW–ESE stress field and that corresponds to Permian dextral wrenching in the Tianshan orogen. Subsequent NE–SW compression led to the third deformation event (D 3) that mainly formed NW–SE-striking reverse faults and NNE–SSW-striking dextral faults. [ABSTRACT FROM AUTHOR]

The Zhuanshanzi gold deposit lies in the eastern section of the Xingmeng orogenic belt and the northern section of the Chifeng‐Chaoyang gold belt. The gold veins are strictly controlled by a NW‐oriented shear fault zone. Quartz veins and altered tectonic rock‐type gold veins are the main vein types. The deposits can be divided into four mineralization stages, and the second and third metallogenic stages are the main metallogenic stages. In this paper, based on the detailed field geological surveys, an analysis of the orebody and ore characteristics, microtemperature measurement of fluid inclusions, the Laser Raman spectrum of the inclusions, determination of CHOSPb isotopic geochemical characteristics, and so on were carried out to explore the origin of the ore‐forming fluids, ore‐forming materials, and the genesis of the deposits. The results show that the fluid inclusions can be divided into four types: type I – gas–liquid two‐phase inclusions; type II – gas‐rich inclusions; type III– liquid inclusions; and type IV – CO2‐containing three‐phase inclusions. However, they are dominated by type Ib – gas liquid inclusions and type IV – three‐phase inclusions containing CO2. The gas compositions are mainly H2O and CO2, indicating that the metallogenic system is a CO2H2ONaCl system. The homogenization temperature of the ore‐forming fluid evolved from a middle temperature to a low temperature, and the temperature of the fluid was further reduced due to meteoric water mixing during the late stage, as well as a lack of CO2 components, and eventually evolved into a simple NaClH2O hydrothermal system. CHOSPb isotope research proved that the ore‐forming fluids are mainly magmatic water during the early stage, with abundant meteoric water mixed in during the late stage. Ore‐forming materials originated mostly from hypomagma and were possibly influenced by the surrounding rocks, suggesting that the ore‐forming materials were mainly magmatic hydrothermal deposits, with a small amount of crustal component. The fluid immiscibility and the CO2 and CH4 gases in the fluids played an active and important role in the precipitation and enrichment of Au during different metallogenic stages. The deposit is considered a magmatic hydrothermal deposit of middle–low temperature. The gold mine is a medium‐ and low‐temperature magmatic hydrothermal deposit. The ore‐forming fluid evolved from a CO2H2ONaCl system to a simple NaClH2O hydrothermal system later. The fluid immiscibility and the CO2 and CH4 gases in the fluids played an active and important role in the precipitation and enrichment of Au during the different metallogenic stages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Qingchengzi and adjacent areas at Liaodong have a high exploration potential for concealed gold mineralization. • Gravity and magnetic signatures used to locate faults, basement and Mesozoic intrusions. • Concealed contacts between granites and Precambrian metamorphic rocks are identified. • Gold deposits are controlled by structural intersections and lithological contacts. The eastern block of the North China Craton (NCC) has been completely decratonized and it hosts numerous early Cretaceous gold deposits dated at about 130–120 Ma. The Jiaodong Peninsula in the easternmost NCC is the largest gold producing district in China, and it hosts more than 150 gold deposits with known gold resources of over 5000 tonnes (t). Also located at the eastern margin of NCC, the Liaodong Peninsula is poorly explored at depths greater than 800 m, with no large concealed gold deposit being discovered yet. In this paper, we carefully analyzed the gravity and magnetic characteristics of the ore-controlling structures in both provinces, including faults, Precambrian basement metamorphic rocks and the Mesozoic granitic intrusions. The deep regional faults are characterized by linear gravity gradient zones or elongated positive magnetic anomalies. The Precambrian basement metamorphic rocks usually have large-amplitude gravity and magnetic highs, while the lithological contacts of Mesozoic granite intrusions are commonly defined by gravity lows or narrow magnetic high anomalies. Interpretations from gravity and magnetic signatures predict two concealed lithological contacts between Mesozoic granites and Precambrian metamorphic rocks beneath Liaodong and Jiaodong. The spatial locations of known gold deposits are then correlated with the concealed structures inferred from the gravity and magnetic data in our paper. Their spatial relationship suggests that the gold mineralization is mainly controlled by oblique regional faults along the structural and lithological contacts between Mesozoic granites and Precambrian metamorphic rocks. Additionally, the structural intersections of different ore-controlling faults, especially the hydrothermal alteration zones at the contacts between Precambrian basement metamorphic rocks and the Mesozoic granites, are most favorable for the gold mineralization in the Liaodong and Jiaodong areas. Many large gold deposits are documented along a deep-seated, but concealed, structure beneath the Jiaodong gold district, while the Qingchengzi ore field and its vicinity in the Liaodong Peninsula still remain underexplored, despite of having a very similar structural setting, and deserve further investigation. [ABSTRACT FROM AUTHOR]

The Lushi gold polymetallic ore-concentration area, located in the southern margin of North China Craton, is an important polymetallic ore district in the Qinling metallogenic belt. The Jianbeigou gold deposit is an important quartz vein type gold deposit in this district. In order to reveal the geological structure of the Jianbeigou gold deposit to guide deep prospecting, the EH4 conductivity image system was used in the Jianbeigou area. The sections obtained by the audio magnetotellurics method (AMT) indicate that the steeply dipping low resistivity zone in the area has a good corresponding relationship with the location of the known shallow ore bodies, and an extension in the deep. The low resistivity anomaly zone obtained by the inversion results are well correlated with the gold mineralization zone of the ore bodies, indicating good deep prospecting and exploration potential in this area. Based on geological and geophysical evidences, this paper inferred the possible occurrence location and depth range of the buried ore bodies. The AMT survey results reflect good exploration potential of the mining area and provide a geophysical basis for deep prospecting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The genesis of the Fenghuangshan gold deposit is considered to be magmatic-hydrothermal. • The Fenghuangshan gold deposit is related to the Paleo-Pacific plate subduction. • The study area is highly prospective for deep-seated gold mineralization. The Jidong area is a vital gold province in North China, including plenty of metamorphic rock-hosted gold deposits. Whether ore-forming fluids are magmatic or metamorphic remains controversial. The genesis for gold mineralization in this gold province is ambiguous. The Fenghuangshan gold deposit lies on the eastern fragment of the Jidong gold province. In this paper, we present a detailed study on ore geology, fluid inclusions, and stable isotopes for the deposit to illustrate the characteristics of ore-forming fluids and ore genesis. The deposit occurs as gold-bearing quartz vein and disseminated- and veinlet-type mineralization. The main orebody named 7# is hosted in migmatitic granite, controlled by NE trending secondary fracture system. Four hydrothermal mineralization stages were identified, including: (Ⅰ) white quartz, (II) pyrite-quartz, (III) quartz-polymetallic sulfide, and (IV) calcite-chlorite-quartz. The Stage II and III belong to main gold mineralization stage. Fluid inclusions from different stages show that a lowering trend of fluid inclusion homogenization temperature was observed. They ranged from 222 °C to 407 °C (early-stage), 144 °C to 375 °C (main-stage), and 86 °C to 174 °C (late-stage), respectively. The salinities of the ore-forming fluids were typically low, ranging from 0.83 to 15.47 wt% NaCl equivalent. On the basis of Laser Raman analysis and fluid inclusion microthermometry, the ore-forming fluids belonged to a low- to moderate-temperature, low-salinity H 2 O-NaCl-CO 2 system. Fluid immiscibility gave rise to rapid gold deposition. The early-stage δD and δ18O H2O values from quartzs ranged from –96.4‰ to –92.5‰ and from 1.74‰ to 2.44‰, whereas main-stage fluids had δ18O H2O values of –4.10‰ to –3.50‰ and δD values of –91.5‰ to –89.5‰. The early- and main-stage sulfide δ34S values varied from –2.0‰ to + 2.2‰, with average values of + 0.4‰. H-O-S-isotope data indicated that the primary ore-forming fluids were magmatic water mixing meteoric water during mineralization, and ore-forming materials were derived from a homogeneous magmatic source. Ore geology, fluid inclusions, and stable isotopes illustrate that the Fenghuangshan gold deposit is a low- to moderate-temperature magmatic-hydrothermal gold deposit. Future deep-seated and surrounding gold exploration should center on this area. [ABSTRACT FROM AUTHOR]

Finding new, effective predictive variables for 3D mineral prospectivity modeling is both important and challenging. The 3D ore-forming numerical modeling quantitively characterizes the complex coupling-mineralization process of the structure, fluid, heat, and wall rock, which may be potential indicators for mineral exploration. We here conducted 3D mineral prospectivity modeling with the integration of ore-forming computational simulation information in the Xiadian orogenic gold deposit, China, to examine whether the simulation data input can improve the reliability of prospectivity modeling. First, we constructed the 3D models of the orebody and fault to extract the fault geometric features using spatial analysis, as they are always considered to be the crucial controls of gold distribution. Second, we performed 3D numerical modeling of the deformation–fluid–heat-coupling process of the structurally controlled hydrothermal Au system using the FLAC3D platform. Finally, the fault-geometry features (buffer, dip, dip variation, and undulation) and the ore-formation-simulation indices (volume strain, shear strain, temperature variation, and fluid flux) were integrated using Bayesian decomposition modeling, which has a promising nonlinear model ability and a flexible variable-integration ability. The prospectivity modeling results demonstrated that the model generated by combining geometry and simulation variables achieved significantly higher AUC, precision, accuracy, Kappa, and F1 scores compared to other models using a single-predictor-variable dataset. This suggests that the joint use of geometry and simulation variables construct a comprehensive association between gold and its ore-controlling factors, thereby resulting in a highly reliable prospectivity model. Thus, the approach of 3D mineral prospectivity modeling aided by ore-forming numerical simulation proves to be more useful in guiding mineral exploration, especially in the condition of fewer variables. Based on the prospectivity modeling outcomes, we identified four gold targets at depth in the Xiadian district that warrant focused exploration efforts. [ABSTRACT FROM AUTHOR]

The Jinying gold deposit is located in southern Jilin Province in northeast China and is representative of the large Early Cretaceous gold deposits in this area. To better understand ore genesis of this deposit, a multi-isotope integrated analysis of U–Pb–Rb–Sr–He–Ar–S has been carried out. Laser ablation inductively coupled plasma–mass spectrometry (LA–ICP–MS) dating of zircons from the granodiorite porphyry and dioritic porphyrite in the study area yields ages of 172.1 ± 1.2 Ma and 122.5 ± 0.8 Ma, suggesting that corresponding intrusion occurred in the Middle Jurassic and the Early Cretaceous. Rb–Sr dating of the pyrite yields an isochron age of 120 ± 3 Ma, suggesting that gold mineralization occurred in the Early Cretaceous. The fluid inclusions in pyrite yield 3He/4He ratios clustered within a small range from 0.08 to 0.13 Ra, 40Ar/36Ar ratios between 331.6 and 351.3, and mantle He in the range of 1.0–1.6%, indicating that the ore-forming fluids originated from a mixed crustal and mantle source. The in situ S isotopic values of pyrite vary between + 0.1 ‰ and + 2.8 ‰, suggesting that the ore-related sulphur came from the deep magmatic source. Combined with the geological history of the study area, it can be concluded that the gold mineralization was possibly related to the extensional setting associated with the rollback of the Palaeo-Pacific Plate. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus type one (HIV-1) infection remains a major public health problem worldwide. Early diagnosis of HIV-1 is crucial to treat and control this infection effectively. Here, for the first time, we reported a novel molecular diagnostic assay called reverse transcription loop-mediated isothermal amplification combined with a visual gold nanoparticle-based lateral flow assay (RT-LAMP-AuNPs-LFA), which we devised for rapid, specific, sensitive, and visual identification of HIV-1. The unique LAMP primers were successfully designed based on the pol gene from the major HIV-1 genotypes CRF01_AE, CRF07_BC, CRF08_BC, and subtype B, which are prevalent in China. The optimal HIV-1-RTLAMP-AuNPs-LFA reaction conditions were determined to be 68°C for 35 min. The detection procedure, including crude genomic RNA isolation (approximately 5 min), RT-LAMP amplification (35 min), and visual result readout (<2 min), can be completed within 45 min. Our assay has a detection limit of 20 copies per test, and we did not observe any cross-reactivity with any other pathogen in our testing. Hence, our preliminary results indicated that the HIV-1-RT-LAMP-AuNPsLFA assay can potentially serve as a useful point-of-care diagnostic tool for HIV-1 detection in a clinical setting. [ABSTRACT FROM AUTHOR]

The Suolong gold deposit is in the eastern part of the Min‐Li metallogenic belt within the West Qinling Orogen. It is hosted in Lower Permian sandstone and siltstone. The gold mineralization is fault‐ and joint‐controlled. Four hydrothermal stages of mineralization, including the sulphide‐quartz stage, the arsenian pyrite‐quartz stage, the polymetallic sulphide‐quartz‐carbonate stage and the sulphide‐carbonate stage, were identified. Here we report results from fluid inclusion studies and C‐H‐O‐S‐Pb isotopes to get insight into the characteristics of mineralization and ore genesis. Fluid inclusion results indicate that the ore‐forming temperatures and salinities were in the range from 135 to 419°C and 0.18 to 15.27 wt.%, respectively. The δ34S values of pyrite, arsenopyrite and pyrrhotite varied in the 5.3‰–11.4‰ range, suggesting that sulphur originated from stratum sulphur. Lead isotopic compositions of sulphide (206Pb/204Pb = 18.344–18.418, 207Pb/204Pb = 15.628–15.701, 208Pb/204Pb = 38.508–38.743) indicate an upper crust source for Pb. The δ18OH2O‐SMOW and δDSMOW values range from 1.01‰ to 10.31‰ and −116.0‰ to −29.2‰, respectively, indicating that metamorphic water was the source of ore‐forming fluids. The δ13CPDB values (−11.4 to −2.1‰) show that the carbon in the ore‐forming fluids originated predominantly from a deep source. Our data suggest that the Suolong gold deposit is an orogenic gold deposit related to the subduction of an oceanic plate along the Mianlue belt. [ABSTRACT FROM AUTHOR]

The recent development in remote sensing imagery and the use of remote sensing detection feature spectrum information together with the geochemical data is very useful for the surface element quantitative remote sensing inversion study. This aim of this article is to select appropriate methods that would make it possible to have rapid economic prospecting. The Qishitan gold polymetallic deposit in the Xinjiang Uygur Autonomous Region, Northwest China has been selected for this study. This paper establishes inversion maps based on the contents of metallic elements by integrating geochemical exploration data with ASTER and WorldView-2 remote sensing data. Inversion modelling maps for As, Cu, Hg, Mo, Pb, and Zn are consistent with the corresponding geochemical anomaly maps, which provide a reference for metallic ore prospecting in the study area. ASTER spectrum covers short-wave infrared and has better accuracy than WorldView-2 data for the inversion of some elements (e.g., Au, Hg, Pb, and As). However, the high spatial resolution of WorldView-2 drives the final content inversion map to be more precise and to better localize the anomaly centers of the inversion results. After scale conversion by re-sampling and kriging interpolation, the modeled and predicted accuracy of the models with square interpolation is much closer compare with the ground resolution of the used remote sensing data. This means our results are much satisfactory as compared to other interpolation methods. This study proves that quantitative remote sensing has great potential in ore prospecting and can be applied to replace traditional geochemical exploration to some extent. [ABSTRACT FROM AUTHOR]

The process and mechanism of gold mineralization are frontier issues. The Dunbasitao deposit is the most important gold deposit discovered along the Armantai suture zone, East Junggar, NW China, which indicates the potential for future ore exploration in this area. Orebodies are mainly hosted in Lower Carboniferous Jiangbasitao Formation volcano-sedimentary rocks, and the ores are characterized by multistage pyrites. Based on microscopy and backscattered electron imaging studies, pyrites are classified into five types: the pre-ore framboidal/colloidal Py0; the early-stage coarse-grained, cubic, and homogeneous Py1; and the middle-stage fine-grained, cubic/pyritohedron Py2 that includes Py2a (core), Py2b (mantle), and Py2c (rim). The results of the EPMA and in situ LA-ICP-MS analyses show that trace elements of pyrite mainly occur in two forms: solid solutions and invisible or visible inclusions. Mn, Co, Ni, and As enter the pyrite lattice, whereas Ti occurs as mineral inclusions, and Au, Cu, Zn, Sb, and Pb can occur in both forms. Au and As show a positive linear relationship with r = 0.850. Py2b has much higher Au contents (20.1 to 201 ppm) than other pyrite types (Py0: 0.01 to 0.36 ppm; Py1: 0.01 to 0.02 ppm; Py2a: 0.31 to 2.48 ppm; and Py2c: 0.18 to 18.0 ppm). The Dunbasitao deposit is classified as an orogenic gold deposit using the two latest machine learning classifiers based on pyrite trace element data. Fluid immiscibility, sudden cooling, and the substitution of S1− with As1− might be crucial mechanisms leading to Au precipitation. Initial ore-forming fluids brought major amounts of As, Au, Co, Ni, Se, Zn, Ag, Cd, Sn, and other elements, and the Jiangbasitao Formation host rocks contributed a certain amount of As, Ni, Cu, Sb, Pb, and Bi, at least. [ABSTRACT FROM AUTHOR]