Sb Deposition Research Articles

Gold and antimony metallogenic relationship of the Awanda Au (Sb) deposit, South Tianshan, NW China: Constraints from textures, in-situ trace elements and s-pb isotope systematics

The Tianshan is one of the most important gold ± antimony metallogenic province in the world. However, the relationship between Au and Sb mineralization remains poorly understood, largely due to lacking of systematic investigation on typical Au-Sb deposits. Here, we reported in-situ trace elements and S-Pb isotopic dataset on the Awanda Au (Sb) deposit, which is currently the second largest gold deposit in Chinese South Tianshan, and contain highly antimony (Sb) by our new petrographic observations. Sulfide from two minelization stages, i.e., Stage Ⅰ (arsenopyrite, pyrite, pyrrhotite, and minor chalcopyrite) and Stage II (gudmundite, aurostibite and stibnite), were analyzed using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). Trace element compositions reveal that ore minerals display positive correlations between As and Au-Sb-Cu-Zn-Pb, implying a common source for these elements. In situ δ34S values of sulfides that cluster in the range of − 2.94 to + 0.8 ‰, suggesting that sulfur contained in Au-As-Sb-bearing fluids were most likely derived from Upper Paleozoic sediments (δ34S = − 1.6 to + 0.3 ‰) during regional metamorphism. In-situ 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios (17.882 to 18.002, 15.467to 15.620 and 37.831 to 38.344) from sulfides are also support that the Upper Paleozoic strata may have supplied substantial metals. Combined with published electron microprobe and fluid inclusions data, our textural and chemical data suggest that fluid-rock interaction and decrease in pressure, temperature, and oxygen-sulfur fugacity were the main cause for Au-As and Au-Sb minelization, respectively. In summary, we propose that the Awanda Au (Sb) deposit fits the crust metamorphic model with Au-As and Au-Sb mineralization occur at mesozonal and epizonal depths, respectively.

Sedimentary antimony stable isotope record of anthropogenic contamination in a karst lake in southwestern China

Anthropogenic sources of antimony (Sb) are an important driver of pollution in the Earth environment, but their roles in the historical changes of Sb pollution in lake ecosystems are currently poorly understood. This study documents the sedimentary Sb deposition fluxes in Hongfeng lake (HFL), in southwestern China during 1958–2021 and quantifies the changes of anthropogenic contributions to sediments using Sb stable isotopes. Mean Sb concentration (mean: 1.89 mg kg−1) and deposition flux (mean: 302.1 ng cm−2 a−1) in lake sediments remained relatively stable from 1958 to 1980. Sb deposition fluxes increased rapidly since 1980, peaked at 990.8 ng cm−2 a−1 in 2000, and then decreased consistently, reaching 306.9 ng cm−2 a−1 in 2021. Generally, the historical changes in Sb isotopes were anticorrelated with Sb deposition fluxes and enrichment factors, suggesting a lower ε123Sb signature in anthropogenic loading sources, and highlight the ability of Sb isotopes to distinguish anthropogenic signatures from natural processes in complex hydrological systems. Using a binary end-member mixing model, the contributions of anthropogenic sources to the accumulated of Sb in the lake sediments were estimated to be 20 % before 1980s and increased approximate 58 % during 2000–2015, then decreased to 24 % in 2021, likely reflecting the changes of degree in regional industrial activities. Our results help to better understand the response of Sb pollutions to anthropogenic activities and would in turn benefit the controls Sb contamination in lake ecosystems.

Characteristics of antimony mineralization in the Yangla polymetallic deposit, northwestern Yunnan, SW China: Insights from calcite Sm-Nd dating and C-O-Sr isotopes

Calcite is the main gangue mineral in antimony (Sb) deposits, and its compositions can reflect the physicochemical conditions of Sb mineralization. The Yangla is the largest Sb deposit (10 kt Sb @ 14.87 %) in the Jinshajiang suture zone (SW China), and the lode-type Sb orebodies are stratabound or developed along NE-trending fracture zones in marble. To constrain the time of Sb mineralization and establish any genetic link with the local magmatism and wallrocks, we performed calcite Sm-Nd dating and bulk C-O and in-situ Sr isotope analyses. The results show that the Sb mineralization (∼155 Ma) was considerably younger than the Cu-Pb-Zn mineralization (∼230 Ma), skarn alteration (∼234 Ma), and granitoid emplacement (∼230 Ma) at Yangla, but much older than the local W mineralization (∼30 Ma). The initial 87Sr/86Sr ratio of calcite (0.71972–0.72208) is much higher than that of the Triassic granodiorite (0.71149– 0.71990) and Carboniferous basalt (0.70562–0.70995), suggesting mixed source of calcite from the ore fluids and Devonian wallrocks. The ore-related calcite has δ13CPDB (−4.53 to − 2.33 ‰) and δ18OSMOW (+14.98 to + 16.30 ‰) values that fall between the granite and marine carbonate isotopic fields. This suggests that the ore-forming fluid may be related to the low-temperature alteration of granites and marine carbonate dissolution. Simulated precipitation temperature calculation for the ore-related calcite yielded 200–150 °C, and the calcite C-O isotopes suggest that fluid mixing, fluid-rock interactions, and CO2 degassing may have precipitated the stibnite in the fracture zones under low-temperature conditions. Our new geochemical results and published data suggest that the Yangla polymetallic mineralization was multiphase, comprising the Indosinian Cu-Pb-Zn (∼230 Ma), Yanshanian Sb (∼155 Ma), and Himalayan W-Sb (∼30 Ma) metallogenic events.

The use of combined C[sbnd]Mg isotope compositions of carbonates from orogenic Sb[sbnd]Au deposits as a tracer of fluid interaction with sea-floor altered crust

The Mesoarchaean Murchison Greenstone Belt is composed of a strongly deformed volcano-sedimentary succession metamorphosed up to amphibolite facies and surrounded by metaluminous and peraluminous granitoids in the north of the Kaapvaal Craton of southern Africa. A circa 40 km-long shear-zone of strongly carbonatised rocks (the Antimony Line, or Sb-Line) oriented along the main trend of the greenstone belt (WSW–ENE) hosts important Sb deposits with accessory Au. These commodities mostly occur as stibnite and native gold hosted by quartz‑carbonate rocks at the centre of the Sb-Line, underlining the importance of CO2-rich fluid flow for mineralisation during deformation and metamorphism.In this study, we compare the elemental and stable isotope (C-O-Mg) composition of carbonates from the Sb-Line with regionally distributed carbonates hosted by the volcano-sedimentary succession distal to mineralisation. The carbonates of the Sb-Line and regional rocks have overlapping major element compositions. Both magnesite and dolomite in most Sb-Line samples have marked light-REE-depleted patterns with variable positive Eu anomalies. Carbon isotope ratios define two clusters, with marked δ13C peaks at ca. -5 ‰ for Sb-Line rocks and ca. -2 ‰ for regional rocks, implying separate C-sources. The peak at ca. -2 ‰ likely represents early carbonatisation through sea-floor alteration, whereas the first peak at ca. -5 ‰ is indicative of deep CO2 (mantle, or magma-derived) introduced during tectonic activity of the Sb-Line. Magnesium isotope ratios of regional rocks reveal limited fractionation (bulk δ26Mg = −0.27 ± 0.10 ‰) that overlap with mantle values, but some carbonate-bearing veins present 26Mg-depleted compositions (bulk δ26Mg = −1.91 to −0.40 ‰). Sb-Line carbonated rocks have more fractionated Mg isotope compositions (bulk δ26Mg = −0.8 to 0.0 ‰) and carbonates display marked negative 26Mg values (δ26Mg from −1.46 to −0.31 ‰). We interpret these results in terms of preferential remobilisation of isotopically light Mg during fluid-rock interaction and dissolution of carbonate in the host-rocks. The lack of correlation between δ13C and δ26Mg indicates decoupling of these isotopic systems, implying contribution from isotopically distinct sources of C and Mg to the mineralised zone.Similar to other structurally controlled AuSb mineralisation in Archaean greenstone belts, metal transport and ore deposition in the Murchison Greenstone Belt was closely related to the deep cycle of carbon, linking C-draw-down during sea-floor alteration, carbonate re-mobilisation during metamorphism and CO2 degassing from deep sources along major crustal discontinuities. In contrast to models for orogenic AuSb deposits invoking a purely intra-crustal, metamorphic origin of mineralising fluids, our results underline the importance of deep-sourced fluids originating from an external source from the volcano-sedimentary succession.

Distribution and Enrichment Mechanisms of Selenium in Stibnite from the Xujiashan Sb Deposit, Hubei Province, China

The Xujiashan Sb deposit located at the Mufushan fold thrust belt of the Yangtze block is one of the most important Sb deposits in this district. Stibnite in this deposit contains high and various contents of Se, but research on the distribution and enrichment of Se in stibnite remains limited. This paper conducts geochemical composition, C-H-O isotopic composition, and scanning electron microscopy morphology of the Xujiashan deposit to discuss the sources of ore-forming materials and fluid, as well as the distribution and enrichment mechanisms of selenium in stibnite. The results showed that the ores have trace element compositions comparable with the wall rocks, and Sb and Se contents are significantly higher than the average carbonate rocks. The δ13CPDB values of calcite and quartz range from −12.8‰ to 5.5‰, the δ18OSMOW values range from 20.4‰ to 24‰, and the δDV-SMOW values range from −57.8‰ to −86.9‰. Trace element and isotope compositions indicate that the ore-forming materials were mainly derived from the wall rocks (sedimentary–metamorphic rocks) that S, Se, and Sb dissolved during fluid–rock interactions. The ore-forming fluids were metamorphic water produced by metamorphism, which had experienced multistage mixing with meteoric water and organic-rich fluids. Selenium substitutes for sulfur in the stibnite crystal lattice, causing rhythmically distributed Se contents in stibnite, which resulted from multistage physicochemical changes in ore-forming fluids during crystallization. The varied patterns of Se contents are the result of different cross-sections of the stibnite.

Floodplain morphology influences arsenic and antimony spatial distribution in a seasonal acid sulfate soil wetland

Arsenic (As) and antimony (Sb) often co-occur in floodplain depositional environments that are contaminated by legacy mining activities. However, the distribution of As and Sb throughout floodplains is not uniform, adding complexity and expense to management or remediation processes. Identifying floodplain morphology predictor variables that help quantify and explain As and Sb spatial distribution on floodplains is useful for management and remediation. We developed As and Sb risk maps estimating concentration and availability at a coastal floodplain wetland impacted by upper-catchment mining. Significant predictors of As and Sb concentrations included i) distance from distributary channel-wetland intersection and ii) elevation. Distance from channel explained 53 % (P < 0.01) and 28 % (P < 0.01), while elevation explained 42 % (P < 0.01) and 47 % (P < 0.01) of the variability in near-total Sb and As respectively. As had a higher extractability than Sb across all tested soil extractions, suggesting that As is more environmentally available. As and Sb dry mass estimates to a depth of 0.1 m scaled to the lower coastal Macleay floodplain ranged from 113–192 tonnes and 14–24 tonnes respectively. Landscape-scale modelling of metalloid distribution, informed by morphology variables, presented here may be a useful framework for the development of risk maps in other regions impacted by contaminated upper-catchment sediments.

Tissue-specific deposition, speciation and transport of antimony in rice.

Rice (Oryza sativa) as a staple food is a potential intake source of antimony (Sb), a toxic metalloid. However, how rice accumulates this element is still poorly understood. Here, we investigated tissue-specific deposition, speciation, and transport of Sb in rice. We found that Sb(III) is the preferential form of Sb uptake in rice, but most Sb accumulates in the roots, resulting in a very low root-to-shoot translocation (less than 2%). Analysis of Sb deposition with laser ablation-inductively coupled plasma-mass spectrometry showed that most Sb deposits at the root exodermis. Furthermore, we found that Sb is mainly present as Sb(III) in the root cell sap after uptake. Further characterization showed that Sb(III) uptake is mediated by Low silicon rice 1 (Lsi1), a Si permeable transporter. Lsi1 showed transport activity for Sb(III) rather than Sb(V) in yeast (Saccharomyces cerevisiae). Knockout of Lsi1 resulted in a significant decrease in Sb accumulation in both roots and shoots. Sb concentration in the root cell sap of two independent lsi1 mutants decreased to less than 3% of that in wild-type rice, indicating that Lsi1 is a major transporter for Sb(III) uptake. Knockout of Lsi1 also enhanced rice tolerance to Sb toxicity. However, knockout of Si efflux transporter genes, including Lsi2 and Lsi3, did not affect Sb accumulation. Taken together, our results showed that Sb(III) is taken up by Lsi1 localized at the root exodermis and is deposited at this cell layer due to lack of Sb efflux transporters in rice.

Biogeochemical prospecting of metallic critical raw materials: soil to plant transfer in SW Ciudad Real Province, Spain

The soil–plant transfer of trace elements is a complex system in which many factors are involved such as the availability and bioavailability of elements in the soil, climate, pedological parameters, and the essential or toxic character of the elements. The present study proposes the evaluation of the use of multielement contents in vascular plants for prospecting ore deposits of trace elements of strategic interest for Europe. To accomplish this general goal, a study of the soil–plant transfer of major and trace elements using Quercus ilex as a study plant has been developed in the context of two geological domains with very different characteristics in geological terms and in the presence of ore deposits: the Almadén syncline for Hg and the Guadalmez syncline for Sb. The results have made it possible to differentiate geological domains not only in terms of individual elements, but also as a combination of major and trace elements using Factor Analysis. The bioconcentration factors have demonstrated the uptake of macronutrients and micronutrients in very high concentrations but these were barely dependent, or even independent of the concentrations in the soil, in addition to high values of this factor for Sb. The Factor Analysis allowed for the differentiation of geogenic elements from other linked to stibnite ore deposits (Sb, S, and Cu). This element (Sb) can be uptake by Quercus ilex via the root and from there translocating it to the leaves, showing a direct relation between concentrations in soil and plants. This finding opens the possibility of using Quercus ilex leaves for biogeochemical prospecting of geological domains or lithological types of interest to prospect for Sb deposits.

Mineralization processes of gold and antimony in northern part of the Youjiang Basin, SW China: Constraints from LA-ICP-MS trace elements of fluorite from the Qinglong Sb (Au) and Nibao Au deposit

Mineralization processes of gold and antimony in northern part of the Youjiang Basin, SW China: Constraints from LA-ICP-MS trace elements of fluorite from the Qinglong Sb (Au) and Nibao Au deposit

Chemical bath deposition of Sb2S3 thin films using the mixing solution of SbCl3 and sodium citrate as a novel Sb source for assembling efficient solar cells

Sb2S3 films are prepared by CBD using the mixing solution of SbCl3 and sodium citrate as a novel Sb source. The CBD growth mechanism of Sb2S3 films is revealed and the CBD growth process is dominated by the nanoparticle formation–adsorption pathway.

Separation of Au and Sb mineralization in the Qukulekedong intrusion-related deposit, East Kunlun Orogen (NW China): Evidence from fluid inclusions, H–O isotopes, and quartz geochemistry

Separation of Au and Sb mineralization from different hydrothermal stages is a common phenomenon in many Au–Sb deposits, but its cause remains enigmatic. The Qukulekedong intrusion-related Au–Sb deposit in the East Kunlun Orogen has undergone four hydrothermal stages: (1) barren quartz vein, (2) quartz vein with disseminated arsenopyrite–pyrite alteration halo, (3) stibnite–quartz ± native gold vein, and (4) calcite–quartz vein. Stages 2 and 3 formed disseminated Au and vein-type Sb ± Au ore, respectively. Here, internal texture and trace elements in quartz, fluid inclusions (Fls) microthermometry, and H–O isotopes were analyzed to unravel the separation mechanism of the Au and Sb ± Au mineralization at Qukulekedong. Stage 2 quartz has euhedral growth zones with elevated Ti-Al-Li-K-Sb and varying As contents. Stage 2 FIs have medium homogenization temperature (203–307 °C) and salinity (12.2–17.8 wt% NaCl equiv.), and are CH4-rich. They have δ18OH2O = 9.5–10.8 ‰ and δDH2O = −93.4 to −80.8 ‰. In contrast, stage 3 quartz has lower Ti-Al-Li-K and varying Sb contents. Stage 3 FIs show phase separation (coexistence of V-, L- and V-L-type FIs), and are of lower temperature (141–164 °C) and salinity (2.1–10.7 wt% NaCl equiv.), and CO2– and CH4-bearing. They have δ18OH2O = 3.3–5.2 ‰ and δDH2O = − 95.4 to − 89.6 ‰. Considering that the disseminated Au ore is Sb-rich and its pyrite has fine stibnite inclusions, we suggest that the disseminated Au and vein-type Sb ± Au mineralization shared a common Au- and Sb-rich initial magmatic fluids. The disseminated Au mineralization may have formed by fluid–rock interactions. Meanwhile, the vein-type Sb ± Au mineralization was likely caused by the phase separation and cooling led by dilational activities and meteoric water injection.

Deciphering the ore-forming process of Sb-W deposits through scheelite and stibnite trace element geochemistry

Antimony (Sb) and tungsten (W) and deposits typically form in distinct and unrelated ore-forming environments. However, in rare cases, ore deposits may present combined Sb-W mineralization within a single deposit. These contrasting occurrences introduce uncertainty within the Sb-W ore deposit model, which ultimately guides mineral exploration strategies. Scheelite and stibnite are prevalent ore minerals in Sb-W deposits, making their trace element compositions valuable for enhancing our understanding of the genesis of Sb-W ore systems. In this study, we conducted a systematic investigation of trace element compositions in scheelite and stibnite samples from the Chashan and Zhazixi Sb-W deposits in South China to decipher the primary ore-forming processes. Scheelite from the Sb-W deposits is characterized by low Na, Nb, Ta and Mo contents, and variable Nb/Ta ratios. These results present a remarkably different geochemical signature when compared with granite-related W deposits, indicating that W mineralization in Sb-W deposits was derived from a non-magmatic origin. Moreover, when combining the trace element signature with reported fluid inclusion and isotopic data, it can be concluded that ore-forming fluids of the Chashan and Zhazixi Sb-W deposits were primarily composed of deep-circulating meteoric groundwater. Scheelite from the Chashan deposit presents relatively flat REE patterns with large positive Eu anomalies, whereas the Zhazixi deposit is characterized by bell-shaped REE patterns with weak Eu anomalies. This suggests that the two Sb-W deposits may differ slightly in their source rock composition, which is also supported by the different trace element compositions of stibnite. Stibnite from the Zhazixi deposit is relatively enriched in As, Se and Pb, whereas stibnite from the Chashan deposit contains higher Sn, Zn, Mo, Ag, In and Sr, further indicating that the initial fluids of the two deposits may have undergone different degrees of fluid-rock interaction with their distinctive source rocks. This study demonstrates that the genesis of the Zhazixi and Chashan Sb-W deposits significantly differ when compared to the ore-forming processes that control granite-related W or metamorphic W deposits. Moreover, the formation of these Sb-W deposits appears to share a similar genetic model consistent with low-temperature Sb deposits in South China. In this model, deep-circulating meteoric groundwater infiltrates and leaches Sb and W from fertile source rocks through fluid-rock interaction. Concealed granites may have solely served as a thermal source for the convection and upward migration of ore-forming fluids, while the fertility of source rocks and the intensity of fluid-rock interaction are expected to have played a crucial role in the formation of Sb-W deposits.

Quasicrystalline Antimony Thin Films

AbstractThe growth of antimony (Sb) thin films on the fivefold surface of icosahedral Ag−In−Yb quasicrystal has been studied by scanning tunneling microscopy (STM) and x‐ray photoelectron spectroscopy (XPS). At low coverage, the deposited Sb yields a network of pentagons of different sizes and heights. These Sb pentagons can be mapped by a pentagonal tiling of the substrate and thus exhibit quasicrystalline long‐range order. Subsequent deposition of Sb yields a disordered film. XPS observations of the growth mode are consistent with the STM results.

The La Lucette Sb-Au-(W) vein-deposit (Armorican Massif, France): New time and genetic constraints to decipher the 310–295 Ma Sb-Au metallogenic peak in the Variscan Belt

In the French Armorican Massif, La Lucette is the most important late Variscan Sb deposit with an uncommon Sb-Au-(W) ore. Detailed mineralogical investigations, fluid inclusion study in gangue and ore combined with in-situ apatite LA-ICP-MS U/Pb dating were carried out to decipher the Sb-Au-W relationships, and metallogenic processes. The mineralization consists of sigmoidal quartz lenses. Four stages of ore deposition have been identified, consisting in the following mineral assemblages: i) scheelite, ii) arsenopyrite, pyrite, iii) base-metals and iv) stibnite-Au. An initial aqueous-carbonic hot-fluid (350 to 250 °C) from a metamorphic source is involved for the early scheelite to base-metals stages, and fluid/rock interaction could be responsible for the scheelite crystallization. Cooling and mixing of the initial fluid with an aqueous cold meteoric fluid (∼200 to 130 °C), are key factors for the late Sb-Au ore-deposition. P-T conditions express a shallow emplacement level (3.5 to 6 km) in a single and progressive crystallization-deformation event. No significant exhumation, and no additional magmatic source from late Variscan felsic or early Carboniferous mafic magmatic events are needed for the Sb-Au-(W) ore genesis. Structural features and new LA-ICP-MS U/Pb apatite dating associated with a regional synthesis show that all major Sb-Au mineralizations of the Armorican Massif, and most from the European Variscan Belt districts have a relatively similar genetic model. In the French Variscan massifs those deposits have been emplaced during the same mineralizing peak, which operated at around 310–295 Ma, and was controlled by the late-orogenic Variscan post-thickening tectonic event.

LA–ICP–MS analysis of sulfides from the Jianzhupo deposit, Guangxi Province, China: Insights into element incorporation mechanisms and ore genesis

The Jianzhupo deposit, the largest Zn-Sb deposit in the Wuxu orefield in China, contains abundant sphalerite and jamesonite, contrasting with typical Sb deposits elsewhere. Whether the Sb and Zn in the deposit derived from similar parental sources is not clearly resolved. Here, trace-element compositions of sulfides from the deposit were determined by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Results indicate that jamesonite is an important Cd-bearing sulfide with Cd contents of 523–764 ppm and minor or no significant Cd variations were observed within jamesonite crystals. Trace-element compositions of jamesonite indicates that Cd enters the lattice by coupled substitution as 2Fe2+ ↔ Zn2+ + Cd2+. Due to similar geochemical behaviors between Zn and Cd in hydrothermal systems, Zn/Cd ratio of sphalerite was suggested as a robust geochemical tracer to distinguish metal sources in such systems. Here, we summarized the Zn/Cd ratios of sphalerite from various hydrothermal systems and the results show that values between 169 and 233, and lower than 44 are from high- and low-temperature temperature fluid conditions, respectively. Due to different Zn/Cd ratios between sediments and igneous rocks, we conclude that metals in sphalerite from the Jianzhupo deposit were likely derived from granite; in contrast, metals in jamesonite were related to sedimentary rocks. These conclusions are consistent with previous studies on the deposit. Overall, our results indicate that ore-forming fluids of the Jianzhupo deposit were derived from magmatic–hydrothermal and basin water. This study extends the application of trace-element compositions in resolving the sources of sulfides in hydrothermal systems.

Mineralization process of the Mazhala Au–Sb deposit, South Tibet: Constraints from fluid inclusions, H-O-S isotopes, and trace elements

The Mazhala deposit is a typical Au-Sb deposit in the northern Himalayan orogenic belt that has increasingly attracted worldwide attentions. However, debates remain regarding the source of ore–forming fluid and its evolutionary process. Herein, we investigate the genetic and compositional evolutionary characteristics of different types of pyrite grains in order to better constrain the ore–forming fluid source and ore–forming processes by means of Using in-situ trace and sulfur isotope data of pyrite and inclusion temperature and H-O isotope data of quartz. Based on the occurrence and morphological features of pyrite, four types of pyrite (Py0, Py1, Py2, and Py3) have been identified. The framboids of pyrite Py0 have high contents of Au, Ag, Cu, Pb, and Sb, with Co/Ni < l, and their δ34S values range from −34.0‰ to −19.3‰, indicating a sedimentary-diagenetic origin. Py1 pyrite exhibits stark core-rim structure. The contents of Sn, Ti, Be and W in Py1c are higher, with Co/Ni > 1. The δ34S of Py1c ranges from 0.30 to 3.9‰ (mean = 1.7‰), indicating a magmatic hydrothermal transformation origin. Py1r, Py2, and Py3 differ greatly in pyrite morphology and trace element contents, with Co/Ni < 1, indicating as hydrothermal sedimentary transformation origin. The δ34S values of Py1r, Py2, and Py3 vary from 1.4 to 6.50‰, interpreted as the presence of metamorphic sulfur sources. The δ34S values of Py1-Py2-Py3 firstly increases and then decreases, indicatinga fluid mixing process. The Mazhala ore–forming fluid is typical of low temperature (270–291 °C), low salinity (1.1–5.0 wt%NaCl equiv) and CO2-enrichment, with H-O isotopic compositions of quartz resembling magmatic and/or metamorphic water, which makes us to infer a mixture of magmatic and/or metamorphic water source for the Mazhala ore-forming fluid. The early pyrite grains were dissolved and reprecipitated under the action of fluid. In the process of multistage hydrothermal interaction, Au and other trace elements were released from the primary pyrite lattice into the fluid, forming the gold–bearing ore–forming fluid. Separation of fluid phase coupled with significant change in the pH value of fluid prompted the co-precipitation of Au and Sb to form the Mazhala Au-Sb deposit.

DFT study of the formation of the Sb-Ag(1 1 1) (√3×√3) – R30° surface alloy

According to performed DFT calculations, the (√3×√3) – R30° structure, in which Sb atoms occupy hcp sites on Ag(111), is more energetically favorable than the related substitutional SbAg2 surface alloy. The difference in energies is significant, 0.66 eV per unit cell, and can be attributed to a larger size of Sb atoms compared to Ag. The obtained results of modeling the substitutional process explain the formation of adsorbed Sb layer on the Ag(111) surface by means of Sb deposition instead of the formation of the substitutional surface alloy. In turn, Ag deposition onto the alloy surface will cause a floating up (segregation to the surface) of Sb atoms thus restoring the alloy surface, which may serve as a surfactant in the process of the growth of Ag crystal.

Contribution of carbonaceous strata to intrusion–related Au mineralization: Evidence from trace elements and S–Pb isotopes in pyrite from the Qukulekedong Au–Sb deposit, East Kunlun, NW China

The large intrusion–related Qukulekedong Au–Sb deposit was recently discovered in the East Kunlun Orogenic Belt (EKOB). Mineralization occurs in the Late Triassic granitoid intrusion and its surrounding carbonaceous siltstone. Pyrite is an important Au-rich mineral in the deposit, and can be classified into three types: Py1, Py2 and Py3. The lattermost Py3 represents the main metallogenic episode. In–situ trace elements and S–Pb isotopes of pyrites indicate that the Py3 has a relatively high Au content (mean 7.84 ppm), high Co/Ni ratios (mean 4.93), with δ34S values around 0‰ (-2.03 to 1.69‰) and matched Pb isotopic ratios to the intrusions, suggesting that Au and other ore-forming material were most likely derived from a magmatic source. Carbonaceous siltstone contains organic carbon up to 3.39 wt%. According to the evidence of paragenetic minerals, texture, and S isotopes, the carbonaceous material may have played a key role in the precipitation of Au and pyrite in the carbonaceous strata. The Au–As decoupling of pyrite in intrusions may be attributed to the Au precipitation and crystallization of arsenopyrite, which was caused by the decreasing of oxygen fugacity. Overall, the new understanding highlights the importance of carbonaceous strata in intrusion–related Au ore-forming processes, the combination of carbonaceous strata and Late Triassic intrusions provides a new exploration direction for Au prospecting in the EKOB and similar settings.

High-kinetic and stable antimony anode enabled by tuning coordination environment for ultrafast aqueous energy storage

Antimony (Sb) with stripping/plating behavior is attractive as anode material for aqueous energy storage. However, it suffers from unfavorable ion diffusion and de-solvation issues due to special coordination environment of Sb(III), resulting in poor rate capability. Herein, we regulate the coordination environment by introducing high-affinity Cl− ligands to achieve high-kinetic and reversible Sb stripping/plating. It enables faster diffusion kinetics and lower de-solvation energy barrier to promote the manageable nucleation and deposition of Sb even at ultrahigh current densities on various of collectors (carbon felt, Ti foil and F-doped tin oxide, etc). Notably, the Sb anode on carbon felt substrate delivers coulombic efficiency of 97.0%, high-rate capability (98.4% capacity retention from 20 to 500 mA cm−2 or 250 C) and satisfactory stability. The as-assembled CoxNiy(OH)z//Sb battery also provides outstanding rate capability and durability. This work provides new inspiration for developing ultrafast Sb-based aqueous energy storage.

Genesis and mineralization implications of dissolution–regrowth pyrite in the large Qukulekedong Au–Sb deposit, East Kunlun, NW China

The Qukulekedong deposit is a recently discovered large Au–Sb deposit in the western part of the East Kunlun Orogenic Belt, NW China. Pyrite with a characteristic dissolution–regrowth texture has developed in the high-grade Au ore of the deposit. In this study, information on the mineralogical properties, elements distribution, and in situ S isotopic composition of the dissolution–regrowth pyrite was used to interpret its genesis and relationship to Au concentration. The pyrite grains are composed of a core, mantle, and rim. The core consists of pyrite with δ34S values ranging from 1.02 ‰ to 1.99 ‰, indicating a neutral pH, medium-oxygen fugacity environment. The mantle consists of sphalerite, sericite, quartz, and ankerite with dissolution texture, indicating pyrite dissolution and replacement in a neutral pH, high-oxygen fugacity environment. The rim consists of pyrite with fine arsenopyrite inclusions and recovers the crystal shape of the pyrite, which have δ34S values ranging from 1.60 ‰ to 2.67 ‰. This indicates that the rim was formed via regrowth in a neutral pH, low-oxygen fugacity environment. The dissolution of the mantle and regrowth of the rim represent an oxygen fugacity increasing–decreasing process in the formation of pyrite. The increase in oxygen fugacity could remobilize Au from dissolved pyrite, forming a highly Au-concentrated hydrothermal fluid. The decrease in oxygen fugacity triggered the supersaturation and precipitation of Au, forming an Au-rich rim. Combining geological characteristics, the pyrite likely had a magmatic sulfur origin and formed via a dissolution-regrowth process caused by the depressurization–oxidation associated with rock fractures. The dissolution-regrowth pyrite can be used as a mineralogical indicator for regional Au exploration.