Sb Deposition Research Articles

Geochronology and geochemistry of ore-hosted zircon reveal the genesis of typical Sb-(Au-W) deposits in South China

The Xikuangshan and Woxi Sb-(Au-W) deposits are the most important Sb-related mineralization in the Xiangzhong metallogenic province, South China. In this study, trace element, U-Pb dating, and Hf isotopic results of zircon in typical ore samples from the Xikuangshan and Woxi deposits provide new insights into metal/fluid sources and mineralization processes. The zircons in different samples from the Xikuangshan deposit have a similar distribution of zircon U-Pb ages with two major groups: 400–500 Ma and 700–900 Ma, which are consistent with those from their host rocks (Devonian strata) and underlying basement rocks (Lengjiaxi and Banxi Groups). By comparison, the zircons from the Woxi deposit have younger U-Pb ages which are the same as contemporaneous magmatism in South China. The 176Hf/177Hf ratios, εHf(t), and TDM1 further proved an original relationship between the younger zircons (with ages < 500 Ma) and magmatism. The systematic trend in the size and roundness of zircons captured from basement rocks for Xikuangshan might be resulting from gravity separation in the sedimentary process which required a stable and long-lasting mineralization process. On the other hand, the homogenous size and roundness of zircons from the Woxi deposit, regardless of zircon ages and sampling locations, might have been caused by a relatively short and intense mineralization process. The differences in the mineralization process for the two deposits lead to different alteration degrees of zircons and are reflected by the variable concentrations of Y, Hf, Pb, and Th, as well as rare earth elements. In the deposit scale, some samples are considered to be altered at high grade and represent the main mineralization stages for the Xikuangshan and Woxi deposits, as their zircons have variable concentrations of trace and rare earth elements. Combined with previous studies, the sources of zircons and mineralizing material are distinct for the Xikuangshan and Woxi deposits: originated from basement rocks (Xikuangshan deposit) and magmatism (Woxi deposit). In addition, stable and long-lasting deep-circulated meteoric water is considered the mineralizing fluid for the Xikuangshan deposit, whereas the mineralizing fluid for the Woxi deposit might be related to magmatism. This research highlights the use of zircon geochronology and geochemistry in revealing the genesis of Sb deposits, making this method applicable worldwide to similar vein-type mineralization.

Genesis of the Yawan Sb deposit, West Qinling Orogen, Central China: Constraints from S–Pb–C–O isotopes and Sm[sbnd]Nd geochronology

The Yawan Sb deposit is a large deposit located in the Xihe County, Gansu, northwestern China. Ore bodies are hosted in the Triassic limestone and are controlled by the NE- trending faults, occurring as lamellar, lenticular, veined, and lentil. Based on the cutting relationship between veins and mineral assemblages, the ore-forming process can be divided into four stages: I) pyrite + stibnite + milky quartz stage, II) stibnite + pyrite + gray-black cryptocrystalline quartz stage, III) stibnite + calcite + fluorite stage, and IV) clear and colorless calcite stage. The δ34S values (−2.5 ‰ to 5.8 ‰) of sulfides from stage II are similar to those associated with magmatic systems, but significantly different from the values (δ34S = −12.8 ‰ to 18.8 ‰) of pyrites from strata, suggesting that magmatic sulfur was the source for S2− in stage II. The δ34S values (−9.5 ‰ to −7.5 ‰) of stibnites from stage III are depleted in 34S relative to those of stage II, probably due to the increasingly mixing of meteoric water and SO42− from the strata. The Pb isotopes of sulfides from stage II and III (206Pb/204Pb = 17.745–19.176, 207Pb/204Pb = 15.478–15.711, 208Pb/204Pb = 37.7–38.742) show a mixed source of crust and mantle. The δ13C and δ18O values of calcites range from −0.84 ‰ to 3.94 ‰ and from 4.74 ‰ to 13.24 ‰, respectively, indicating that the ore-forming fluids originated from magmatic water, but influenced by water-rock interaction and meteoric water in the late stage. The SmNd isochron age of five calcite simples from stage III is 199.9 ± 1.7 Ma (MSWD = 1.6) with initial εNd values of −8.4, indicating that Yawan Sb deposit formed in the Late Triassic to Early Jurassic. On the basis of the data obtained in this paper, we consider that the Yawan Sb deposit is a distal magmatic-hydrothermal deposit formed during the transitional tectonic regime from the syn-collision to post-collision. Combined with previous studies, future exploration should focus on the distal magmatic-hydrothermal Sb deposits controlled by faults around concealed granites, and skarn-type deposits also need attention in Yawan-Daqiao district.

Multivariate statistical analysis and risk assessment of dissolved trace metal(loid)s in the cascade-dammed Lancang River

As a prominent factor impacting water quality, the dissolved trace metal(loid) (DTM) has not been adequately studied in the Lancang River Basin (LRB). Herein, we sampled surface water from 46 sites in the LRB to explore the spatial distribution, primary sources, and associated human health risks of 18 DTMs (As, Ba, Cd, Co, Cr, Cs, Cu, Li, Mo, Ni, Pb, Rb, Sb, Sr, Tl, U, V, and Zn). Affected by geothermal spring input, the concentrations of As, Cs, Li, Mo, Sr, and U were significantly higher in the mainstream than those in tributaries, with a decreasing trend along the flow direction in the mainstream of the LRB. Tl and Rb are mainly related to naturally derived sources, like soil erosion, Cd, Cr, Cu, Pb, and Zn were mainly attributed to anthropogenic processes, Co and Ni were affected by both natural and anthropogenic processes, while Sb was mainly from the Sb deposit in the basin. As a result of the combined influence of multiple sources of pollution, the spatial distribution of these elements does not seem to be regular. Most of the DTM concentrations in the LRB were within the Chinese and WHO drinking water guideline values, while 43.5% of the samples contained arsenic exceeding the guideline value of 10 µg/L. In general, the water quality of the LRB was good. Health risk assessment indicated that As, Sb, and Tl were the primary drivers of the non-carcinogenic risk. These results give the scientific basis needed for metal(loid) cycling in the aquatic environment and the ecological management of the LRB.

In-situ trace elements and sulfur isotopic analyses of stibnite: Constraints on the genesis of Sb/Sb-polymetallic deposits in southern China

The Xiangzhong metallogenic province (XZMP), the largest polymetallic mineralization province in southern China, is known for its large number of Sb and Sb-polymetallic deposits (>100). In this study, detailed microscope observation, trace element, and sulfur isotopic analyses were performed on stibnite from the Xikuangshan, Woxi, and Banxi deposits in the XZMP to constrain the ore genesis.Stibnite from three deposits appears similar under backscattered electron imaging and has similar major elements contents. Detectable trace elements in stibnite are Fe, Cu, Zn, As, and Pb. Base metals (Cu, Pb, and Zn) are enriched in stibnite from the Woxi deposit but are depleted in stibnite from the Xikuangshan and Banxi deposits. Gold is detectable only in stibnite from the Woxi deposit. Cu, As, and Pb mainly occur as solid solutions within the crystal lattice in stibnite, while micro-scale inclusions of Fe- and/or Zn-rich phases are also observed. The δ34S values of stibnite from three deposits are distinct but with narrow ranges: +6.8 to +10.2 ‰; +5.5 to +6.5 ‰; −4.2 to +0.1 ‰ for the Xikuangshan, Banxi, and Woxi deposits, respectively. The δ34S values of stibnite suggest that the underlying basement rocks are the potential source of sulfur for the Sb mineralization in the Xikuangshan and Banxi districts while sulfur for the Sb mineralization of the Woxi district may have originated from a deep magmatic source. In addition, a positive trend between the δ34S values of stibnite and sampling depth suggests an input of the 34S-rich basin brine during the mineralization in the Woxi district.We propose a genetic model for the Sb mineralization in the XZMP: Fluids rich in Sb, Au, W, Cu, Pb, and Zn related to igneous activities ascended via regional deep faults and mixed with 34S-rich basin brine. Ore minerals of Sb, Au, and W were deposited within structural traps resulting in the Woxi-type deposits. The basement-derived deep fluids driven by orogenic leached Sb and related metals from the basement metamorphic rocks, which migrated via the regional faults and mixed with cold near surface meteoric water to form the Xikuangshan-type deposits.

Genetic significance of trace elements in hydrothermal quartz from the Xiangzhong metallogenic province, South China

Despite the Xiangzhong metallogenic province being globally the most important ore-concentrated area of antimony (Sb) mineralization, the genesis of Sb-(Au-W) deposits in this region is still under debate. In this study, trace element compositions of hydrothermal quartz from four representative Sb-(Au-W) deposits (Xikuangshan, Woxi, Banxi, and Zhazixi) in the Xiangzhong metallogenic province have been investigated to constrain the origin of ore-forming fluids and physiochemical conditions of Sb mineralization. The fsLA-ICP-MS data indicate that Li, B, Na, Al, P, K, and Sb are relatively enriched in quartz, probably mainly incorporated into the quartz crystal lattice, and dominated by the coupled substitution of (Al3+, Sb3+, B3+) + (Li+, Na+, K+, H+) ↔ Si4+ and (Al3+, Sb3+, B3+) + P5+ ↔ 2Si4+. In the Xikuangshan Sb deposit, charge-neutrality conditions of cations reveal that (Al3+, Sb3+) + Li+ ↔ Si4+ is the most important substitution mechanism in quartz from early-stage Sb mineralization (quartz-stibnite veins), whereas (Al3+, Sb3+) + (Li+ + H+) ↔ Si4+ may control the trace element contents in quartz from late-stage Sb mineralization (calcite-quartz-stibnite veins). The relatively high Al content and the low variability in trace element content suggest that quartz from the Xikuangshan Sb deposit may have precipitated from a relatively acidic and stable ore-forming fluid. Combined with the high Sr and Rb contents of quartz, a plausible explanation is that acidic hydrothermal fluids promoted water–rock reaction that dissolved large amounts of Sr and Rb, resulting in the high Al, Rb, and Sr contents in crystallized quartz from the Xikuangshan Sb deposit. In contrast, the relatively low but inhomogeneous Al content indicates that quartz from the Woxi and Banxi Sb-(Au-W) deposits may have precipitated from a less acidic ore-forming fluid and supports the idea of fluid mixing. More importantly, the relatively high contents of Rb, Ge, and Ti in quartz from the Woxi and Banxi Sb-(Au-W) deposits, combined with the low Al and Sr contents, imply that magmatic-hydrothermal systems possibly contributed to the ore-forming fluids. Based on the trace element compositions of quartz, two major types of Sb deposits were identified in the Xiangzhong metallogenic province: the giant Xikuangshan epithermal deposit in which the ore-forming fluids are relatively acidic, stable and have experienced water–rock reaction, generally similar to the Qinglong Sb deposit in the Youjiang metallogenic province. The second type is the orogenic-type deposit represented by the Woxi Sb-Au-W deposit, including the Banxi Sb deposit, where the ore-forming fluids have undergone fluid mixing and relatively weak water–rock reaction, and may have been joined by a small amount of magmatic-hydrothermal fluids. Together with the recently published Sb mineralization ages (149–144 Ma) of the Woxi Sb-Au-W deposit, it supports the idea that this type of Sb deposit is related to the Mesozoic magmatism. The Zhazixi Sb-W deposit shows transitional features between these two types of Sb deposits.

Genesis of the Sanshiliuwan Sn-Pb-Zn-Sb deposit in the Xianghualing ore district (Southern Hunan, South China): Constraints from geology, fluid inclusion analyses, and geochronology

Tin (Sn) and antimony (Sb) deposits commonly formed in distinctive environments and thus the coexisting of Sn and Sb mineralization in a single deposit is rarely recognized worldwide and the genesis of this type of deposit remains poorly understood. The newly discovered Sanshiliuwan Sn-Pb-Zn-Sb deposit in the Xianghualing ore district of Southern Hunan has metal reserves of 44,000 t Sn, 291,000 t Pb + Zn, and 20,000 t Sb and average grades of 0.39 % Sn, 4.91 % Pb + Zn, and 1.00 % Sb, and thus offers an ideal window for prospecting the genesis of the Sn-Pb-Zn-Sb deposit. The orebodies in the deposit were mainly hosted in Cambrian and Devonian sequences and occurred as veins. Three mineralization stages were recognized including the cassiterite-sulfide, Pb-Zn-Sb sulfide, and carbonate. The fluid inclusions in the quartz from the cassiterite-sulfide stage (QtzI) have homogenization temperatures of 418–244 °C (typically 400–320 °C) and salinities in the range of 0.87–10.11 % NaClequiv. While the fluid inclusions in the quartz from the Pb-Zn-Sb sulfide stage (QtzII) have the homogenization temperatures of 253–141 °C (typically 250–180 °C) and salinities in the range of 0.18–9.86 % NaClequiv. The fluid inclusions in quartz from different mineralization stages have low Na+/K+ ratios in the range of 0.05–0.96 and clustered Cs/Rb ratios of 2–5, indicating that the ore fluids of the deposit were likely to have been exsolved exclusively from a magmatic source. Cassiterite U-Pb dating suggested that the Sanshiliuwan deposit formed ca. 155 Ma, which is well coincided with the concealed granites (formed ca. 156 Ma). Therefore, the genetic model for this deposit would demonstrate that evolved fluids from Jurassic granites invaded the faults and deposited Sn and Sn-Pb-Zn ore veins in the granite periphery. Thence, Sn-depleted but Pb-Zn-rich fluids interacted with the Sb-rich Cambrian sequence and leached it to create Sb-rich fluids. In response to fluid cooling and boiling, Pb-Zn-Sb-rich fluids then deposited Pb-Zn-Sb sulfide ore veins at favorable structural sites.

Directly Deposited Antimony on a Copper Silicide Nanowire Array as a High‐Performance Potassium‐Ion Battery Anode with a Long Cycle Life

AbstractAntimony (Sb) is a promising anode material for potassium‐ion batteries (PIBs) due to its high capacity and moderate working potential. Achieving stable electrochemical performance for Sb is hindered by the enormous volume variation that occurs during cycling, causing a significant loss of the active material and disconnection from conventional current collectors (CCs). Herein, the direct growth of a highly dense copper silicide (Cu15Si4) nanowire (NW) array from a Cu mesh substrate to form a 3D CC is reported that facilitates the direct deposition of Sb in a core‐shell arrangement (Sb@Cu15Si4 NWs). The 3D Cu15Si4 NW array provides a strong anchoring effect for Sb, while the spaces between the NWs act as a buffer zone for Sb expansion/contraction during K–cycling. The binder‐free Sb@Cu15Si4 anode displays a stable capacity of 250.2 mAh g−1 at 200 mA g−1 for over 1250 cycles with a capacity drop of ≈0.028% per cycle. Ex situ electron microscopy revealed that the stable performance is due to the complete restructuring of the Sb shell into a porous interconnected network of mechanically robust ligaments. Notably, the 3D Cu15Si4 NW CC is expected to be widely applicable for the development of alloying‐type anodes for next‐generation energy storage devices.

Material Source and Genesis of the Daocaowan Sb Deposit in the Xikuangshan Ore Field: LA-ICP-MS Trace Elements and Sulfur Isotope Evidence from Stibnite

The Daocaowan antimony (Sb) deposit is a newly discovered Sb deposit located outside the northeast Xikuangshan ore field. In the absence of geochemical data, the metallogenic mechanism of the Daocaowan Sb deposit and its relationship with the Xikuangshan ore field remains unclear. Using high-resolution LA-ICP-MS technique, this study quantitatively determined the in-situ S isotope values and trace element composition of stibnite from the Daocaowan Sb deposit in South China to investigate the source of ore-forming materials and genesis of this deposit. The trace element compositions of stibnite from the Daocaowan Sb deposit revealed the form of occurrence and substitution mechanism of trace elements in stibnite, providing new constraints for explaining the genesis of Sb deposits. The relatively smooth LA-ICP-MS profiles indicate that As, Cu, Hg, and Pb primarily occur as solid solutions in stibnite. Therefore, we speculate that the substitution 3Sb3+↔As3+ + 2Cu+ + Hg2+ + Pb2+ may be the reason for the enrichment of As, Cu, Hg, and Pb in stibnite. A comparison with the Xikuangshan Sb deposit reveals the metallogenic mechanism of the Daocaowan Sb deposit, and the relationship between the two. With the exception of higher content of Fe in Stibnite from the Daocaowan deposit as compared to the Xikuangshan deposit, other trace elements are similar between the two deposits. The results show that the Daocaowan and Xikuangshan Sb deposits may have the same source of ore-forming fluids. We propose that the ore-forming fluid flowed through the Xikuangshan Sb deposit along the F75 fault and dissolved pyrite in the wall rock. Subsequently this fluid containing a high concentration of Fe precipitated and mineralized at Daocaowan. Meanwhile, the S isotope value of the Daocaowan Sb deposit (+6.65 to +9.29‰) is consistent with that of the Xikuangshan, proving that the ore-forming materials of the two deposits are from the same source, probably the basement strata. We propose that the Daocaowan Sb deposit is part of the Xikuangshan ore field, indicating a great prospecting potential in the northeast of the Xikuangshan ore field.

Evaluation of antimony availability in a mining context: Impact for the environment, and for mineral exploration and exploitation.

This work aims to establish Sb mobility, its transfer to biota and its effect on soil health in a semi-arid climate. The results show the presence of stibnite (Sb2S3) as the main primary Sb compound, bindhemite (Pb2Sb2O6(O,OH)), and minor proportions of stibiconite (Sb3+(Sb5+)2O6(OH)) as oxidised Sb species. This research also observes very high total Sb contents in mining materials (max: 20,000 mg kg−1) and soils (400–3000 mg kg−1), with physical dispersion around mining materials restricted to 450 m. The soil-to-plant transfer is very low, (bioaccumulation factor: 0.0002–0.1520). Most Sb remains in a residual fraction (99.9%), a very low fraction is bound to Fe and Mn oxy-hydroxides or organic matter, and a negligible proportion of Sb is leachable. The higher Sb mobility rates has been found under oxidising conditions with a long contact time between solids and water. The main factors that explain the poor Sb mobility and dispersion in the mining area are the low annual rainfall rates that slow down the Sb mobilisation process and the scarce formation of oxidised Sb compounds. All these data suggest poor Sb (III) formation and a low toxicological risk in the area associated with past mining activities. The low mobility of Sb suggests advantages for future sustainable mining of such ore deposits in a semi-arid climate and is also indicative of the limitations of geochemical exploration in the search for new Sb deposits.

Atmospheric deposition and trajectories of antimony in Central Europe

Antimony (Sb) concentrations were measured in wet atmospheric deposition at 10 high-elevation sites in the Czech Republic (Central Europe) during three winter seasons (2009–2011). Soluble and insoluble Sb forms were quantified in snow (vertical deposition) and rime (horizontal deposition) on mountain summits located equidistantly near the Czech borders with Austria, Germany and Poland. The highest Sb concentrations were found in the soluble form in rime (0.47 μg L−1), while the lowest Sb concentrations were those in the insoluble form in snow (0.017 μg L−1). The estimated average Sb deposition rate in Central Europe amounted to 1.3. 10−4 g m−2 yr−1. Most Sb was deposited in the soluble form in snow (7.9. 10−5 g m−2 yr−1), followed by the soluble form in rime (3.5. 10−5 g m−2 yr−1). The corresponding insoluble fraction contained less Sb, namely 1.2. 10−5 g m−2 yr−1 in snow and 2.3. 10−6 g m−2 yr−1 in rime. The average Sb deposition in Central Europe, measured at an altitude of 1000 m a.s.l., was by six orders of magnitude higher compared to Sb deposition in the Arctic (7. 10−10 g m−2 yr−1), and by four orders of magnitude lower compared to Sb deposition in a Sb–Hg mining district in China (7 g m−2 yr−1). Using the HYSPLIT model, backward trajectories of air masses indicated that the Sb sources were predominantly situated in Upper and Lower Silesia.

Occurrence, distribution, and migration of antimony in the Zijiang River around a superlarge antimony deposit zone

Under the environmental changes associated with mine tributaries entering mainstream rivers, differences in the distributions and migration behaviors of metal(loid)s can be found, but the behavior of antimony (Sb) is still poorly understood in this regard. We analyzed the occurrence, distribution, migration, and influencing factors of the Sb concentration in the water body of the Zijiang River (ZR) around a superlarge Sb deposit zone. The total Sb concentrations were 1.45–15.66 μg/L, 3.16–133.63 mg/kg, and 0.83–41.82 μg/L in the ZR surface waters, sediments, and pore waters, respectively; Sb(V) was the predominant form of Sb found in the surface waters. Mining and smelting were the main sources of Sb in the ZR. Spatially, the Sb concentration showed a decreasing trend from the tributaries to the ZR mainstream. In the ZR, the surface-water Sb concentration showed an increasing trend from the upstream to the downstream, while in the sediments and pore waters, the midstream Sb concentrations were higher than the upstream and downstream concentrations; this finding was related to the sediment retention and accumulation behaviors of reservoirs and dams resulting in the secondary release of Sb in sediments. Sb tended to be bound to the solid phase, dominated by amorphous iron (Fe)/aluminum (Al) oxides and calcium in sediments. This study highlights that, based on current Sb migration patterns, the accumulation of sediments carried by tributaries near Sb mines in the midstream ZR and the Sb pollution caused by sediment release will be long-term, and the related environmental consequences need to be further predicted.

Telescoped boiling and cooling mechanisms triggered hydrothermal stibnite precipitation: Insights from the world’s largest antimony deposit in Xikuangshan China

AbstractSociety annually consumes 250% more Sb relative to the year 1960 and a sustainable supply of antimony depends critically on understanding the precipitation mechanism of stibnite (Sb2S3) that is the globally predominant source of this important technology metal. Previous solubility studies revealed that antimony is transported in mesothermal hydrothermal fluids mainly as the aqueous species thioantimonite (H2Sb2S4, HSb2S4−, Sb2S42−) and hydroxothioantimonite [Sb2S2(OH)2]. Thioantimonite can transform to hydroxothioantimonite with a decline of H2S concentration. However, whether this transition occurs in hydrothermal systems and its role in stibnite precipitation are unknown. In this work, bulk Sb isotope measurements for stibnite from the world’s largest Sb deposit in Xikuangshan China were conducted to address ore fluid evolution and stibnite precipitation mechanisms. The abundance of the stable antimony isotopes 121Sb and 123Sb were measured in stibnite from the Xikuangshan orebodies and reported as δ123Sb. The δ123Sb values show a trend of decreasing first and then increasing from proximal to distal parts of orebodies. This reveals that 123Sb had been preferentially partitioned from the ore fluid into stibnite first, then 123Sb remained preferentially dissolved in the ore fluid. These data indicate that the dominant Sb-complex transforms to Sb2S2(OH)2 from H2Sb2S4 with consumption of H2S. Speciation diagram considerations indicate that stibnite precipitation from the ore fluid was controlled by two telescoped processes: (1) boiling of the ore fluid induced a decrease in H2S that reduced the solubility of H2Sb2S4, and (2) subsequent cooling that induced a decrease in the solubility of Sb2S2(OH)2. This study highlights that understanding the controls of Sb isotope fractionation is critical to constrain fluid evolution and stibnite precipitation mechanisms in Sb-rich mineral systems. In particular, the stable Sb complex in the hydrothermal ore fluid may change during fluid evolution and affect the isotope fractionation mechanism.

A comprehensive genetic model for the world’s largest Sb deposit (Xikuangshan, China)

AbstractThe Mesozoic (160–130 Ma), fault-controlled Xikuangshan Sb deposit within Devonian limestone strata of Hunan Province, Southern China is the world’s largest Sb deposit containing a proven reserve of ~2.5 m Sb. Although mined for over a century, its genesis remains poorly understood. Here we use new He-Ar isotope data of hydrothermal stibnite and both new and existing C-O-Sr-Nd isotopes of hydrothermal calcite with known stages to decipher its genesis and the major constraints on mineralization intensity. The 3He/4He and 40Ar/36Ar ratios of fluid inclusions trapped in stibnite are from 0.01 to 0.04 Ra (Ra: atmospheric 3He/4He ratio) and 304–1077, respectively, indicating the ore-forming fluids at Xikuangshan were dominated by air-saturated meteoric groundwater after interaction with crustal rocks. Ore-stage calcite C and O isotopes indicated that most CO2 in the fluids was acquired from marine carbonate rocks by dissolution; whereas Sr and Nd isotopes differed from deposited Devonian country rocks but were similar to the underlying regional Proterozoic clastic rocks in the region. Calcite from early and late stages showed a strong positive correlation between δ18O and 87Sr/86Sr, consistent with the mixing between the circulating groundwater and compounds released from the Proterozoic rocks due to extensive fluid-rock interaction. The 3He/Q ratios of the fluid inclusions are low, varying from 4.3 to 18.5 × 10−15 cm3 standard temperature and pressure (STP) J−1, indicating deep-seated magma could have provided heat by conduction but no volatiles into the ore-forming fluids. Based on these new results, we suggest that deep-seated granitic magma heated the down-going meteoric groundwater along fault zones, after which the groundwater extensively interacted with and extracted Sb from the Proterozoic Sb-rich rocks to form Sb-rich fluids. The Sb-rich fluids then ascended through regional faults and deposited Sb as stibnites at favorable structural traps to form the Xikuangshan Sb deposit. This study highlights that extensive water-rock interaction is essential to form the deposit, and more intensive water-rock interaction at an early stage allowed for early-stage mineralization yielding higher Sb reserves (&amp;gt;80%) at Xikuangshan.

In Situ U-Pb Geochronology of Calcite from the World’s Largest Antimony Deposit at Xikuangshan, Southern China

The Xikuangshan antimony (Sb) deposit is the world’s largest known Sb deposit. Due to the lack of suitable minerals for reliable high-precision radiometric dating, it remains difficult to determine the exact age of Sb mineralization in this deposit. Here, we report the first LA-MC-ICP-MS U-Pb ages of syn-stibnite calcite from this deposit. The dating results indicate the presence of at least two stages of Sb mineralization in the Xikuangshan ore district. The calcite-stibnite veins in the Daocaowan ore block probably formed during the Paleocene (58.1 ± 0.9 Ma), representing an early stage of Sb mineralization, while the quartz-stibnite vein in the Feishuiyan ore block probably formed during the Eocene (50.4 ± 4.4 Ma, 50.4 ± 5.0 Ma, and 51.9 ± 1.6 Ma), representing a late stage of Sb mineralization. The new calcite U-Pb ages are significantly younger than the calcite Sm-Nd ages (124.1 ± 3.7 Ma, 155.5 ± 1.1 Ma) reported by previous researchers. We suggest that Sb mineralization of the South China antimony metallogenic belt may be related to tectono-thermal events during Paleogene, possibly linked to high heat flow during the subduction (ca. 60–40 Ma) of the Pacific Plate beneath the Eurasian Plate and/or the Indo–Asian Collision (began at ca. 61 Ma). The young in situ U-Pb ages of calcite challenge the idea of late Mesozoic Sb mineralization in the South China antimony metallogenic belt, suggesting the requirement for more high-precision dating studies.

A general ore formation model for metasediment-hosted Sb-(Au-W) mineralization of the Woxi and Banxi deposits in South China

Metasediment-hosted Sb-(Au-W) deposits occur widely in the Jiangnan Orogen (South China), but their complicated metallogenic histories are still under debate. Ore formation models such as syngenetic (SEDEX), granitoid-related, and orogenic scenarios have been proposed by previous studies, but their metal provenance and fluid evolutionary processes are still uncertain. In this study, two typical Sb-(Au-W) deposits (Woxi and Banxi) from this region were studied by in-situ geochemical and geochronological analyses of sulfides to establish a general ore formation model for this type of deposit. Two stages of gold-related pyrite (Py1 and Py2) and one stage of stibnite in the Woxi Sb-(Au-W) deposit, and two stages of arsenopyrite (Apy1 and Apy2) and stibnite (Stb1 and Stb2) in the Banxi Sb deposit were differentiated. Compared to Py1, Py2 is depleted in V but enriched in Au, As, Bi, Pb and Ag, with more negative δ34Sv-CDT and lower Pb isotopic values. Compared with stibnite at Woxi, stibnite at Banxi has higher but more variable contents of most trace elements (e.g., Li, Mg, Al, Si, Cu, Pb, Co, Ni, Fe, Sr and Mn, except for As) and lower Pb isotopic ratios. At Banxi, Stb2 has lower Fe, Cu, Pb, Co, Ni, Sr and Mn contents than Stb1, and Apy2 has higher Co, Ni, Zr, Ti, and Nb contents than Apy1. Analyses of Re-Os isotopes in four samples yielded an isochron age of 439 ± 3.4 Ma (2σ) for Apy1, with an initial 187Os/188Os of 0.3373 ± 0.0009. The above results indicate that early-stage Au mineralization at Woxi may have been orogeny-related, and that ore metals were derived mainly from local epimetamorphic sedimentary rocks with limited input from magmatic fluids. In contrast, the late-stage Sb mineralization at Banxi may have been influenced by deep granitic magmatism. We propose that the common temporal and spatial mineralization sequence of the metasediment-hosted Sb-(Au-W) ores is: orogenic-type gold (early stage; at deep levels of the ore field) → orogenic + magmatic-hydrothermal W (middle stage; at middle levels) → magmatic-hydrothermal + meteoric water Sb (late stage; at shallow levels). Both local metasedimentary rocks and granite magmatism provide metals and ligands for mineralization, with magmatic fluids playing an essential role in late-stage ore formation. Metasediment-hosted Sb-(Au-W) ores in this region exhibit similarities to both orogenic-type and intrusion-related gold systems.

Ex-situ n-type heavy doping of Ge1-xSnx epilayers by surface Sb deposition and pulsed laser melting

Ge1-xSnx alloys have attracted considerable attention for their promising electrical and optical properties. One of the main challenges for their successful implementation in devices concerns the fabrication of n-type heavily doped surface layers. In this work, a new methodology for ex-situ doping of Ge1-xSnx layers is investigated. It consists of the deposition of Sb atoms on the surface of Ge1-xSnx layers followed by pulsed laser melting (PLM) that ensures the diffusion of Sb into the alloy. We demonstrate that Sb is incorporated very efficiently within a relaxed Ge0.91Sn0.09 epilayer, with supersaturated 4 × 1020 cm−3 active concentrations, in line with literature records obtained in Ge1-xSnx with in-situ approaches. At the same time, we observe that the concentration of substitutional Sn close to the surface decreases from 9 to about 6 at. % after PLM, inducing a contraction of the lattice parameter perpendicular to the underlying Ge1-xSnx. These results demonstrate a possible route for ex-situ n-type heavy doping of Ge1-xSnx alloys, but indicate also that Sn redistribution and precipitation phenomena need to be carefully considered for a successful process development.

Vapor Transport Deposition of Sb2(S,Se)3 Solar Cells with Continuously Tunable Band Gaps

Vapor Transport Deposition of Sb₂(S,Se)₃ Solar Cells with Continuously Tunable Band Gaps

Formation of the Banxi Sb deposit in Eastern Yangtze Block: Evidence from individual fluid inclusion analyses, trace element chemistry, and He-Ar-S isotopes

The Banxi Sb deposit (>100,000 t Sb metal with a grade of 0.02%–64.5% Sb (typically 15.3%–25.9% Sb) in the Eastern Yangtze Block is hosted in Neoproterozoic low-grade metamorphic clastic rocks of the Banxi Group. The deposit is characterized by vein-type Sb-only mineralization. Analyses of individual quartz-hosted fluid inclusions obtained by LA-ICP-MS identified Na as the most abundant cation (thousands to tens of thousands of ppm) in the ore-forming fluids of the Banxi Sb deposit, together with variable contents of K, Ca, Al, As, Fe and Sb (tens to thousands of ppm). Multiple chemical criteria, including high Na+/K+ (typically 3–15) and low Mn2+/Na+ (0.003–0.2) and Sr2+/Na+ (0.001–0.01) ratios of individual fluid inclusions, suggest that the fluids responsible for quartz and stibnite precipitation in the Banxi Sb deposit were likely dominated by basinal brines within low-grade metasedimentary rocks. Moreover, the extremely low 3He/4He ratios (0.001–0.048Ra) but relatively high 3He/36Ar (0.5 × 10−5–5.8 × 10−4) and 40Ar/36Ar ratios (323–1111 with an average of 737) of fluid inclusions trapped in ore-stage quartz further support a sedimentary origin of ore-forming fluids in this deposit. The positive and homogeneous sulfur isotopic values (δ34S = 8.0–9.5‰) of stibnite and arsenopyrite are comparable to those of sulfides in Proterozoic metasedimentary rocks (δ34S = 5.6–11.5‰), indicating these metasedimentary rocks may have served as the primary source of S for the Banxi Sb deposit. Combined with geological features and new trace element chemistry data for quartz and stibnite, we envisaged a new formation model for the Banxi Sb deposit that assumes that circulation of weakly alkaline basinal brines through faults under an extensional tectonic setting during the Early Cretaceous (∼130 Ma), mobilization of Sb and S from the underlying and host metasedimentary rocks and ascent of ore- forming fluids along faults, and ultimately precipitation of Sb minerals in or around fault/fracture zones as a result of the decreasing pH of the ore-forming fluids as well as sulfidation during fluid-rock reaction.

Fingerprinting the metal source and cycling of the world’s largest antimony deposit in Xikuangshan, China

AbstractThe Xikuangshan antimony (Sb) deposit is the largest Sb deposit in the world; however, the metal source and cycling and a holistic understanding of the deposit genesis remain equivocal. Sulfur isotope signatures offer a means of fingerprinting different sources in a hydrothermal deposit, although one must be careful to rule out subsequent isotope fractionation during fluid ascent, mixing, and ore precipitation. Here, we investigated the sulfur isotope composition of stibnite occurring at depth in the Xikuangshan deposit to distinguish the isotopic signals from the source and the superimposed imprint from near-surface–derived sulfur mixing or isotopic fractionation. All stibnites from the deep orebodies displayed limited δ34S variation from +6.8‰ to +8.4‰, despite their widely varying depths. These results provide direct evidence that δ34S values measured in deep orebodies are representative of the isotopic composition of initial fluids. The most likely factor controlling the variation of the sulfur isotopes in shallow stibnites (+3.5‰ to +16.3‰) is a series of hydrothermal processes, including Rayleigh fractionation during ore precipitation, fluid boiling induced by pressure release, and/or local input of pyrite from wall rocks via fluid-rock interaction. Accordingly, we conclude that the Neoproterozoic basement served as the metal source. We propose a holistic genetic model wherein we envisage that Sb and S were leached from the basement rocks, and the ore-bearing fluids ascended along a deep fault and eventually precipitated beneath the Devonian shale cap. Thus, sulfur isotopic systematics represent a powerful repository for interrogating the metal source and cycling in the hydrothermal ore system.

Effect of alloying on the electrochemical performance of Sb and Sn deposits as an anode material for lithium-ion and sodium-ion batteries

Effect of alloying on the electrochemical performance of Sb and Sn deposits as an anode material for lithium-ion and sodium-ion batteries