Source Of Gold Research Articles

Indicator typomorphic features and potential sources of small-size placer gold from the Ebelyakh area (northeast Siberian platform)

«Вестник Санкт-Петербургского университета. Науки о Земле» — научно-теоретический рецензируемый журнал, обобщающий результаты исследований в области геологии, гидрогеологии и геохимии, петрологии и экологии, ландшафтного планирования и геоморфологии, экономической и социальной географии.

Geologic structure of the Mukodek gold field (northern Transbaikalia) and sources of matter (Pb-Pb and Sm-Nd data)

The Mukodek gold field is located in the Yana zone of the Baikal-Muya fold belt (northern Transbaikalia). Its orebodies are gold-bearing metasomatites confined to the fault of NE strike. It is shown that pre-ore faults played a crucial role in the spatial localization of the orebodies, as they favored the concentration of ore-bearing fluids. Results of geological and structural studies, along with available geochronological data (40Ar-39Ar dates for micas in gold-bearing pyrite), testify to ore-forming processes in the ore field during two Late Paleozoic stages. Early gold-bearing metasomatites of sericite-chlorite-albite-ankerite-quartz composition formed at 320 Ma, and late gold-bearing vein metasomatites of ankerite(calcite)-quartz composition originated at 285 Ma. A Pb-Pb isotope study of gold mineralization has shown that ore lead was supplied into the mineral-forming system mainly from a mantle source, most likely, regional Neoproterozoic igneous rocks. According to Sm-Nd isotope data, these rocks formed with the participation of a material of mantle genesis.

Constraints on depositional conditions and ore-fluid source for orogenic gold districts in the West Qinling Orogen, China: Implications from sulfide assemblages and their trace-element geochemistry

Yangshan, Mian-Lue-Ning and Manaoke represent three large orogenic gold districts in the Triassic West Qinling Orogen, the third largest gold province in China (∼1100 t gold resource). Although their component gold deposits have similar geological characteristics, representative deposits from these three gold districts have contrasting ore-mineral assemblages and gold speciation suggestive of diversity in gold source and/or ore-forming depositional conditions or processes. Decrease in P-T conditions of ore formation and metamorphic grades of host rocks in deposits from the Mian-Lue-Ning through Yangshan to Manaoke districts is matched by variation in their mineral paragenesis from pyrite–chalcopyrite–sphalerite–galena–native gold through pyrite–arsenopyrite–stibnite to scheelite–pyrite–arsenopyrite–stibnite–realgar. Invisible gold in the deposits of the Yangshan and Manaoke gold districts, contrasts with native gold in the Mian-Lue-Ning gold district. Concentrations of Ag–As–Au-Bi-Cu–Pb–Sb-Tl in hydrothermal pyrite show a gradual systematic increase from Mian-Lue-Ning through Yangshan to Manaoke. Pyrite in the Huachanggou gold deposit from the Mian-Lue-Ning district has high Co and low As and Au concentrations, in contrast with pyrite which is zoned with respect to As and Au in gold deposits from the other two districts. These variations between gold deposits in the different districts could be due to variable local ore–fluid sources derived from the different host-rock sequences during metamorphic devolatilization, as also allowed by mass-balance calculations. However, previously unmetamorphosed voluminous source rocks that have experienced amphibolite facies metamorphism, with liberation of gold and other metals during conversion of gold-bearing pyrite into pyrrhotite, are limited. It appears more likely that an external deeply-sourced fluid, most logically from devolatilization of the pyrite-bearing sediment wedge above the Triassic subduction zone associated with the formation of the West Qinling Orogen, was responsible for gold mineralization. In this model, variation between districts was due to fluid interactions with contrasting host-rock sequences under contrasting P-T conditions.

Synthesis and characterization of gold-containing oxides of K2NiF4 or Nd2CuO4 structure type

In this work, different materials of Nd2CuO4 and K2NiF4 Ruddlesden-Popper structure have been prepared by solid-state reaction in air and high temperatures. The powders of mixed oxides, of general formula La2Li0.5M0.5 − xAu x O4 (M = Cu, Ni), were prepared from [Au(NH3)4](NO3)3 as gold source. The stoichiometric proportions of the all reagents (including La2O3, NiCO3, CuO) were grounded with a LiOH excess as mineralizer, pressed to form into pellets and heated in static air at temperatures between 750 and 850 °C for several hours. Structural characterization of the synthesized oxides using X-ray diffraction (XRD) are presented. La2Li0.5Au0.5O4, La2Li0.5Cu0.5O4, and La2Li0.5Ni0.5O4, three previously known oxides, were obtained. As expected, La2Li0.5Ni0.5O4 and La2Li0.5Cu0.5O4 consist of an ordered K2NiF4 Ruddlesden-Popper structure, while the La2Li0.5Au0.5O4 compound exhibits a Nd2CuO4 type structure. On the other hand, the preparation of the new proposed group La2Li0.5M0.5 − xAuxO4 (x = 0.0125–0.5) containing gold and nickel/copper simultaneously, under the studied conditions, was not possible. The experimental results revealed that the host structures are intolerant with respect to M (Cu or Ni) and Au cation double substitution. The difficulty to obtain the new phases is discussed regarding the exceptional instability displayed by the trivalent state of gold ion (Au3+) and the soft interactions of this specie with the lithium cation. Finally, the monophasic oxides, more interesting in terms of catalytic activity, were analyzed by temperature-programmed reduction (TPR-H2).

Trace Elements in Ancient Gold Products with PGE Microinclusions from Archaeological Sites of the Urals and North Black Sea Region: LA–ICP–MS Data

Many archaeological gold products of the Urals and North Black Sea region contain microinclusions of platinum group minerals (PGMs). The trace element composition of these products was studied using LA–ICP–MS to reveal their microgeochemical features, the differences in the trace element composition of PGM‐bearing and PGM‐free products, and the source of gold. Owing to the presence of microinclusions of ruthenium, osmium and iridium, the gold products from the Filippovka I grave field and the Phanagoria site are enriched in Os, Ru, Ir and Rh. Among the platinum group elements (PGEs), Pt exhibits the highest contents in the gold products. The gold products are characterized by individual assemblages of Ag and base metals. The gold products with both PGEs and base metals were manufactered from two types of gold: placer‐derived and gold from oxidation zones of polymetallic volcanic‐hosted massive sulphide deposits. It is suggested that cupellation was most common technique of gold refinement.

Stable isotope (C-O-S) and geochemical studies of auriferous quartz carbonate veins, Neoarchaean orogenic Ajjanahalli and Gadag Gold Field, Chitradurga schist belt, Dharwar Craton, southern India: Implication for the source of gold mineralizing fluids

Carbon (δ13CPDB) and oxygen (δ18OSMOW) isotopic compositions of carbonates of auriferous quartz-carbonate veins (QCVs), S-isotope (δ34SCDT) composition of gold bearing sulphide minerals and REE geochemical characteristics of the auriferous QCVs of Ajjanahalli and Gadag Gold Fields in the Neoarchaean Chitradurga-Gadag greenstone belt, Dharwar Craton, southern India have been studied in detail to constrain the source of auriferous vein fluids. The carbonate δ13C values of the auriferous QCVs of Ajjanahalli fall in the range −2.09 to −8.59‰ (average: −4.5 ± 1.5‰); δ18O are in the range 11.27–26.12‰ (average: 15.69 ± 4.12‰). The δ13C and δ18O values of carbonates of the BIF that host the auriferous QCVs respectively are −1.54 to −2.00‰ (average: −1.76 ± 0.19‰) and 14.12–26.36 (average: 21.9 ± 5.6‰). The carbonates from the carbonated metabasalts, also host for QCVs show δ13C values between −1.39 and −1.92‰ (average: −1.59 ± 0.24‰) and δ18O between 11.44 and 12.91‰ (average: 11.88 ± 0.6‰). δ13C and δ18O of QCVs are clearly distinct from those of meta-sedimentary carbonates in BIF and carbonates in carbonated metabasalts.The calculated isotope composition of the original fluid for the auriferous QCVs δ13C∑c are in the range −2.97‰ to −9.45‰ (average: −5.2 ± 1.4‰) and δ18OH2O fall in the range between 6.46 and 20.58‰ (average: 7.8 ± 0.95‰). The δ13C and corresponding δ13C∑c values of the QCVs are comparable to those of mantle derived fluids or those emanating from juvenile magmas (−6 ± 2‰). Though many of the δ18OH2O values are similar to those of mantle or juvenile magmatogenic fluids (−8 ± 2‰), some are heavier. These heavier δ18O and δ18OH2O values are shown to have resulted from post-vein emplacement water–rock interaction at lower temperatures.Mantle/juvenile magmatic source for fluids is also indicated by the S-isotope (δ34SCDT) composition of gold bearing sulphide minerals. Pyrite δ34Spy of Ajjanahalli and GGF fall in the range −0.21 to 5.8‰ (average: 3.08 ± 1.82‰) and 0.93 and 3.36‰ (average: 1.98 ± 0.82‰) respectively. The arsenopyrite δ34Sasp values range between 1.09‰ and 3.8‰ (average: 2.95 ± 1.08‰) for Ajjanahalli and 2.84‰ for Gadag. The corresponding sulphur isotope composition of the original fluids δ34SH2S (calculated from δ34SCDT values) for Ajjanahalli gold deposit is in range −0.03 to 4.6‰ (average of 1.89 ± 1.82‰). For the GGF, the values range from −0.17 to 2.11‰ (average: 0.88 ± 0.82%). All these δ34SCDT and their corresponding δ34SH2S are very close to juvenile δ34S values (i.e. 0 ± 2%) confirming the mantle/juvenile magmatic origin of the mineralizing fluids.Mantle/juvenile origin of auriferous fluids for auriferous QCVs from both the areas is also supported by initial Sr isotope ratios as low as 0.702 and positive ∈Nd values up to +10 or higher.LILE, HFSE, REE geochemistry of the auriferous QCVs are also consistent with the above conclusions based on isotope data. The QCVs of both these deposits show +ve Eu anomaly which is typical for hydrothermal fluids of mantle origin. The LILE and HFSE data of the QCVs show that fluids required for them have not been generated by melting of subducted slabs.It is therefore concluded that the new isotope and geochemical data provide convincing evidence for direct involvement of auriferous fluids of mantle origin for these orogenic gold deposits.

Gold/Periodic Mesoporous Organosilicas with Controllable Mesostructure by Using Compressed CO2

Gold nanoparticles confined into the walls of periodic mesoporous organosilicas (PMOs) with controllable morphology have been successfully fabricated through a one-pot method by using different CO2 pressures. The synthesis can be easily conducted in a mixed aqueous solution by using HAuCl4 as gold source and bis[3-(triethoxysilyl)propyl] tetrasulfide and tetramethoxysilane as the organosilica precursor. P123 and compressed CO2 served as the template and catalytic/regulative agent, respectively. Transmission electron microscopy, N2 adsorption, and X-ray diffraction were employed to characterize the structure of the obtained composite materials. To further investigate the formation mechanism, a series of ordered PMOs with one-dimensional nanotube, two-dimensional hexagonal, vesicle-like, and cellular foam structures were obtained by using different CO2 pressures without the gold source. The mechanism for mesostructure evolution of PMOs with different CO2 pressures was proposed and discussed in detail. The catalytic performance of Au-based PMOs was evaluated for the reduction of 4-nitrophenol (4-NP). These obtained composites with different mesostructures not only exhibit excellent catalytic activity, high conversion rate, and remarkable thermal stability, but they also exhibit morphology-dependent reaction properties in the reduction of 4-NP. The possible reaction pathway of the reactants to embedded Au active sites was proposed and schemed.

Constantine’s Introduction of the Gold Solidus

In the Roman Empire of 3rd century AD was subject to serious hyperinflation, which was caused by the overproduction of the denarius, which by this point contained minimal amounts of silver. At the end of the century Diocletian attempted to solve this problem by fixing the prices of goods but was unsuccessful. Constantine I during his reign in the early 4 th century AD introduced a new gold currency, the solidus, which successfully brought down inflation. The solidus had a consistent weight and a floating exchange rate with the base-metal currency. The result of this was a stable denomination that acted in some respects as a gold standard. Constantine was able to accomplish what previous emperors could not because of two extraordinary events: his conversion to Christianity and the discovery of a new source of gold in the reign of his son Constantius II. His conversion to Christianity allowed him to confiscate the wealth from pagan temples. The accounts of these confiscations by Eusebius were previously thought to have been primarily laudative. Recent work done by Kevin Wilkinson on the dating of Palladas, another contemporary writer, has shown that these confiscations were a reality. These two events supplied the empire with enough gold to effectively jump-start his economic strategy. A better understanding of these events is achieved by examining modern historical parallels. These are the confiscations of Jewish property in Germany during the 1930s, Spain’s economy after discovering New World gold and Brazil’s use of a floating exchange-rate to stop hyperinflation.

Direct and one-step synthesis of polythiophene/gold nanoparticles thin films through liquid/liquid interfacial polymerization

This work demonstrates a simple and one-step synthesis of polythiophene/gold nanoparticles (PT/Au) nanocomposite thin films, through a liquid–liquid (L/L) interfacial polymerization route. Starting from an aqueous solution of tetrachloroauric acid (acting both as metallic gold source and oxidizing agent to start the oxidative polymerization of thiophene), and a solution of thiophene in n-hexane, a biphasic L/L system was originated. In the following, the interface acted as a meeting-point for the reactants, and the polymerization reaction took place, leading to self-assembled PT/Au film between the two immiscible liquids. These films were easily deposited over different substrates (glass, silicon, plastics) and characterized through different techniques. The influence of both the reactants ratio and the reaction time on the structure and morphology of the films were evaluated. The films obtained with a shorter reaction time exhibited spherical gold nanoparticles (around 3 nm diameter) homogeneously dispersed into a polymeric matrix. The increase of both the reaction time and the thiophene/gold precursor ratio led to agglomerated and anisotropic gold structures wrapped by a thin layer of polythiophene. Overall, PT/Au films are transparent, homogeneous, stable, flexible and presented reversible electrochromic properties, which make them suitable for application in different systems and devices, as demonstrated here for electrochromic application.

Theoretical and experimental studies of the influence of gold ions and DMH on cyanide-free gold electrodeposition.

Quantum chemical calculations based on density functional theory (DFT) were employed to determine an appropriate gold source for gold electroplating and to ascertain the stable structures of gold-complexes in cyanide-free electrolyte. Based on the charge distribution of 5,5-dimethylhydantoin (DMH) and the bonding energy of gold complexes, Au3+ is the appropriate gold source for DMH-based gold electroplating electrolyte to get greater cathodic polarization and [Au(DMH)4]− with 2N(4)–Au coordination structure is the most stable form of gold ion in the electrolyte. The influence of DMH, used as the complexing agent, on electrochemical behaviors was investigated using cathodic polarization, cyclic voltammetry, and chronoamperometry measurements. With DMH as the complexing agent, the cathodic polarization of gold electrodeposition was significantly enhanced. DMH concentration was determined as 0.30 mol L−1 based on the investigation of the influence of the DMH concentration on cathodic polarization and gold electrodeposit micromorphology. The kinetic features based on cyclic voltammogram measurements revealed that the electrodeposition was an irreversible process under diffusion control with 0.30 mol L−1 DMH as the complexing agent. The ion and electron transfers were obviously inhibited by DMH. The gold electrodeposition process displayed progressive nucleation according to the Scharifker and Hills nucleation model with various applied potentials. The growth rate of the crystal nucleus was reduced by DMH and promoted by a negative shift of Eap.

Prediction of possible primary sources of gold-platinoid mineralization within the Lena-Viluy interfluve (East Siberian platform)

«Вестник Санкт-Петербургского университета. Науки о Земле» — научно-теоретический рецензируемый журнал, обобщающий результаты исследований в области геологии, гидрогеологии и геохимии, петрологии и экологии, ландшафтного планирования и геоморфологии, экономической и социальной географии.

Brown coals of Far East – natural resource for multipurpose industrial processing

The analysis of the potential economic value of brown coals of the Far East of Russia is carried out when to use them as a complex chemical mineral resource. It was conducted assessment of industrial attractiveness to use coal combustion or coal chemical processing wastes as an additional source of gold, rare metals and rare earth elements. The Sergeevskoye brown coal deposit of the Zeya-Bureya Sedimentary Basin in the Amur Region was proposed as a potential standard facility for the construction of a coal-chemical processing plant to produce resin, montan wax, complex hydrocarbons with associated gold, rare metals and rare earth elements recovery.

Interpreting three Gold Coins from Ancient Egypt and the Ancient Near East at the Museo Casa de la Moneda, Madrid

The aim of this paper is to study three gold coins from the pre-Hellenistic Egypt and Near East, housed in the Museum Casa de la Moneda, Madrid, since 1955. In all three cases, their description is made as well as a review of the hypotheses that have been issued on their typology. Some novel proposals are made about their iconography and the possible gold sources for the raw material. The first is a Daric, probably coined between the beginning of the reign of Xerxes I and the fall of Sardis under Alexander the Great. The study provides an original indication about its iconography, as well as about the possible (and vague) relationship of Persian imperial coinage with Zoroastrianism, the official religion of the Achaemenid Dynasty. The nbw nfr coin is an Egyptian coinage from the Nectanebos Dynasty; one of the few hundred preserved copies. The iconography of the horse on the obverse is explored from the art and plastic of pre- and post-Sebenitic Egypt, and some technical aspects of the elaboration of the coin from the type of its reverse are analysed. From an epigraphic point of view, a new reading of the nbw nfr group is proposed. The Double Daric is a complex currency, both regarding the precise determination of its chronology, as well as its interpretation and recipients. It is a coinage made possibly in Babylon with a broad chronology from 331 BCE until ca. 306 B

Une source de l’or pyrénéen et son exploitation dans l’Antiquité

L’or des Pyrénées était connu des auteurs anciens et des recherches archéo-géologiques récentes l’ont mis en évidence sur le plateau de l’Assaladou, entre Sorgeat et d’Ignaux, au S-E d’Ax-les-Thermes en Ariège. Cette source primaire jusque-là inédite a été localisée par la présence d’anciens chantiers miniers à ciel ouvert. Repérés par des prospecteurs du BRGM et de la COGEMA à la fin des années 1970, ils ont été ensuite inventoriés (30 fosses), fouillés et datés par notre équipe entre 1993 et 1997, puis une étude minéralogique a été menée en 2000 et 2016. Deux groupes de travaux remarquables ont été étudiés : une fosse et un ensemble comprenant une mine à ciel ouvert prolongée par une galerie longue de 13 m. La fosse sondée a pu être datée des IIIe-IVe s. de notre ère grâce à une base de foyer conservée sur la sole. L’autre ensemble étudié (fosse et galerie) a confirmé cette datation avec la découverte de charbons de bois, résidus d’un abattage au feu et d’une céramique. Le plateau est constitué de schistes du Cambro-ordovicien, recoupés par des veines et des stockwerks de quartz. Le minerai suivi par ces travaux miniers comprend des lentilles de quartz dur, blanc à gris. Un grand nombre de failles ont recoupé le minerai et les roches encaissantes, facilitant l’abattage. L’or est visible à l’œil nu et se trouve dans le quartz en remplissage de cavités et il est aussi associé à l’arsénopyrite. Les mineurs antiques n’ont pas épuisé le gisement, laissant du minerai riche, accessible en surface. Ils semblent avoir fréquenté de façon saisonnière les lieux, tels des bergers (mineurs/paysans) exploitant un peu de minerai quand le plateau était déneigé.

Features of Inner Structure of Placer Gold of the North-Eastern Part Siberian Platform

Mineral and raw material base of placer and ore gold is based on prognosis evaluation, which allows to define promising areas regarding gold-bearing deposit prospecting. But there are some difficulties in gold primary source predicting and prospecting at the North-east Siberian platform, because the studied area is overlapped by thick cover of the Cenozoic deposits, where traditional methods of gold deposit prospecting are ineffective. In this connection, detailed study of typomorphic features of placer gold is important, because it contains key genetic information, necessary for development of mineralogical criteria of prognosis evaluation of ore gold content. Authors studied mineralogical-geochemical features of placer gold of the Anabar placer area for 15 years, with a view to identify indicators of gold, typical for different formation types of primary sources. This article presents results of these works.In placer regions, where primary sources of gold are not identified, there is need to study typomorphic features of placer gold, because it contains important genetic information, necessary for the development of mineralogical criteria of prognosis evaluation of ore gold content. Inner structures of gold from the Anabar placer region are studied, as one of the diagnostic typomorphic criteria as described in prominent method, developed by N.V. Petrovskaya [1980]. Etching of gold was carried out using reagent: HCl + HNO3 + FeCl3 × 6H2O + CrO3 +thioureat + water. Identified inner structures wer studied in details by means of scanning electron microscope JEOL JSM-6480LV. Two types of gold are identified according to the features of inner structure of placer gold of the Anabar region. First type – medium-high karat fine, well processed gold with significantly changed inner structure. This gold is allochthonous, which was redeposited many times from ancient intermediate reservoirs to younger deposits. Second type – low-medium karat, poorly rounded gold with unchanged inner structure. Poor roundness of gold particles and preservation of their primary inner structures indicate close proximity of primary source.

Gold leaf: From gilding to the fabrication of disposable, wearable and low-cost electrodes

Gold is among the most used materials in electrocatalysis. Despite this, this noble metal is still too expensive to be used in the fabrication of low cost and disposable devices. In the present work, gold-leaf sheets, usually employed in decorative crafts and wedding candies, is introduced as an inexpensive source of gold. Planar-disc and nanoband gold electrodes were simply and easily manufactured by combining gold leaf and polyimide tape. The planar disc electrode exhibited electrochemical behavior similar to that of a commercial gold electrode in 0.2molL−1 H2SO4; cyclic voltammetry of a 1mmolL−1 solution of potassium ferricyanide (K3[Fe(CN)6]) in 0.2molL−1 KNO3, using this novel electrode, displayed an 80mV difference between the oxidation and reduction peak potentials. The electrode also delivers promising prospects for the development of wearable devices. When submitted to severe mechanical deformation, this electrode exhibited neither loss of electrical contact nor significant variation in electrode response, even after fifteen bending and/or folding cycles. The thickness of the gold-leaf sheet facilitates the production of nanoband electrodes with behavior similar to that of ultramicroelectrodes. The electrode surface is easily renewed by cutting a thin slice off its end with a razor blade; this process led to limiting currents that were reproducible, presenting a relative standard deviation (RSD) of 3.8% (n = 5).

Uatú Júpú: a history of the indigenous Rio Doce

This essay examines the long history of resistance by Jê speaking indigenous peoples who have inhabited the basins of the Doce River and its many tributaries. It provides an overview from the colonial era to the present, examining the disparate perceptions and uses that Portuguese and Jê-speaking indigenous peoples have applied to river systems in Brazil. For native communities, the Doce is a source of both spiritual and material sustenance. Portuguese explorers, settlers, and miners viewed rivers as potential transportation and sources of gold and gems. This mutually conflictive history contributes to our understanding of why and how access to rivers has mattered historically and continues to matter in the wake of the Fundão Dam breach in Mariana, Minas Gerais, in 2015.

Extraction of gold (Au) particles from sea water by Delftia Acidovorans microbes

Gold-mining activities have been an issue, especially when it involves in contamination of chemicals, for example arsenic and mercury. However, despite of these hazards, gold-mining activities are still being conducted. This is because the gold is worth, regardless of the problems. Gold-mining, as known needs a very large area of land, or site plant. Vast amount of labor force, mechanical force and fund are a must in order for the mining process to be continued. High demand of gold, made gold-mining industries as ones of the most profitable industries in the world. Thus, this has encouraged another alternative way to extract gold. At the mining site, researchers found that biomineralization of gold by Delftia acidovorans can be conducted. How it is done still cannot be understood. It is said that the bacteria secretes secondary metabolites, Delftibactin as a defensive mechanism against the toxicity of the soluble gold. Researchers try to find another source of elemental gold besides of the earth’s core. The options are either lava of a volcano or ocean. Here, the focus is seawater. The problem of seawater is that its composition still not yet to be proved. Dissolve gold existed as gold chloride in seawater, but in a very small amount. So, the gold separation should be focused, in order to make this process to be a successful one. Factors such as depth, climate, region, temperature need to be considered. If this difference affecting the separating process, standardized seawater composition have to be proposed.

Noble gases in pyrites from the Guocheng-Liaoshang gold belt in the Jiaodong province: Evidence for a mantle source of gold

Abstract The recent mineral exploration programme (2009–2014) in the Jiaodong gold province identified the new Guocheng-Liaoshang gold metallogenic belt which contains reserves of 92 tonnes (t) Au. In the main deposits the ore is fault-hosted in massive sulfides that make up to 25 to 95 vol%. The He-Ar isotope compositions of ore-forming fluids from 20 pyrite samples from the five main deposits are reported here. 3 He/ 4 He range between 0.41 and 2.39 R a , 40 Ar/ 36 Ar are 367 to 2112 and 40 Ar ⁎ / 4 He are 0.40–3.78. The data require four gas sources; a dominant mantle-derived component plus sub-ordinate crustal radiogenic, meteoric and basin brine components. The mantle end-member has 3 He/ 4 He (3.32–4.00 R a ). This is lower than most estimates for sub-continental lithospheric mantle (SCLM: 6–7 R a ), implying that it was probably refertilized by subduction-related fluid metasomatism. This is consistent with He-Ar isotopes reported for SCLM xenoliths from basalts in the Shandong Province. Within the mineralisation province, the mine Au reserve is positively correlated with the proportion of mantle-derived He in the ore-forming fluids. This implies that the fluids, and by inference the gold, was largely derived from mantle melts during lithospheric extension. Given the conspicuous association of gold ore deposits with mantle-derived magma in the Jiaodong Peninsula, we envisage that our genetic model can be applied, to some extent, to evaluate the potential of some mineral exploration targets.

Synthesis method of asymmetric gold particles

Asymmetric particles can exhibit unique properties. However, reported synthesis methods for asymmetric particles hinder their application because these methods have a limited scale and lack the ability to afford particles of varied shapes. Herein, we report a novel synthetic method which has the potential to produce large quantities of asymmetric particles. Asymmetric rose-shaped gold particles were fabricated as a proof of concept experiment. First, silica nanoparticles (NPs) were bound to a hydrophobic micro-sized polymer containing 2-chlorotritylchloride linkers (2-CTC resin). Then, half-planar gold particles with rose-shaped and polyhedral structures were prepared on the silica particles on the 2-CTC resin. Particle size was controlled by the concentration of the gold source. The asymmetric particles were easily cleaved from the resin without aggregation. We confirmed that gold was grown on the silica NPs. This facile method for synthesizing asymmetric particles has great potential for materials science.