Sn Deposits Research Articles

Insights into deep metallogenic setting inSEChina based on geophysical data

SE China is regarded as one of the most important mineral resource bases in China. The spatio‐temporal distribution of the magmatism and mineralization in the area has a distinct pattern due to the uneven intensity of crust–mantle interactions. We analysed gravity, magnetic and magnetotelluric (MT) data from the study area. The lithosphere in the north‐eastern and coastal parts of South China features intense magnetic, low resistivity anomalies and low density of lithospheric mantle material components. Meanwhile, the crust in the Nanling region features high resistivity and low magnetic granitic pluton. As we view from the north‐east to the south‐west, the crust–mantle interaction in SE China weakens unevenly and the magmatic origins for ore‐forming are progressively shallow. In the continental margin area, the subducted plate partially melted and rose along deep faults, interacting with the lithospheric mantle, which created conditions for the formation of the large porphyry Cu deposits. In the inland Nanling region, the Palaeo‐Pacific Plate has subducted to a considerable depth, the influence of deep disturbances was diminished, and therefore the metallogenic magmas of W–Sn deposits are dominated by continental crust remelting granites. While the tectonic environment of the Pb–Zn–Ag polymetallic deposits is in a transitional zone between porphyry Cu deposits and W–Sn deposits, small amounts of femic magma mixed with large amounts of granitic magma to form the mineralized granites. The geophysical data provide corresponding evidence to support the mineralization dynamics model based on oblique Pacific subduction.

Chemistry and U–Pb geochronology of cassiterite in the Xiasai deposit, central Yidun Terrane (SW China): Link between Sn and Ag–Pb–Zn mineralisation

Tin and (Ag)–Pb–Zn mineralisation generally co-exist in SEDEX, porphyry, skarn, greisen, as well as magmatic-hydrothermal Sn and/or Pb–Zn polymetallic deposits. The genetic relationship between these two styles of mineralization, however, is not well defined. More than 20 skarn and hydrothermal-vein-type Ag–Pb–Zn–Sn deposits can be found in the central Yidun Terrane (YDT) of southwestern China. Amongst these is the large Xiasai deposit, which contains 1028 t Ag @ 337.8 g/t, 0.27 Mt Pb + Zn @ 8.33 %, and 20,000 t Sn @ 0.75 %. The deposit is zoned, comprising proximal cassiterite-quartz veins and distal Ag–Pb–Zn veins. We present micro-textural studies, LA–ICP–MS U–Pb dating results, as well as cassiterite major and trace element data that served to better constrain the link between the Sn and Ag–Pb–Zn mineralisation at Xiasai. Two types of cassiterite, i.e., Cst I and Cst II, can be distinguished using cathodoluminescence (CL) imagery. Cst I has a dull luminesce and oscillatory zonation, and it has been partially replaced by Cst II, which has a bright luminesce and a homogeneous texture. Whistle the SnO2 and TiO2 contents of Cst I and Cst II are similar, the latter has slightly higher FeO compositions (from bdl to 0.08 wt% and 0.01 to 0.11 wt%, respectively). LA–ICP–MS U–Pb dating of cassiterite yielded a Tera-Wasserburg U–Pb lower intercept age of 99.2 ± 0.8 Ma (n = 39, MSWD = 1.8), identical to the ages of granitic magmatism and Ag–Pb–Zn vein formations. LA–ICP–MS trace element analyses revealed that cassiterite is enriched in Ti and W, but depleted in Fe, Mn, Nb, and Ta. The Zr/Hf ratios of cassiterite range from 4.7 to 15.8 and Ti/Zr ratios range from 1.8 to 6.2. Overall, the measured Fe, W, Nb, and Ta concentrations, as well as the calculated Zr/Hf and Ti/Zr ratios, indicate that the cassiterite-quartz veins at Xiasai have a magmatic-hydrothermal origin. Our findings, when combined with previous micro-thermometrical fluid inclusion data (423–481 °C for Sn and 158–386 °C for Ag–Pb–Zn mineralisation), suggest that Sn and Ag–Pb–Zn mineralisation was cogenetic and linked to a common magmatic-hydrothermal system. The spatial relationship between Cretaceous A-type granitic magmatism and Ag–Pb–Zn–Sn mineralisation in the central YDT can be used as a guideline for mineral exploration of both skarn and hydrothermal veins.

Geochronology and geochemical characteristics of ore-forming granite in Maopengdian Sn deposit, northern Jiangxi Province

The Maopengdian tin-polymetallic deposit is located in the eastern sector of northern Jiangxi Province. The geological and petrographic characteristics of muscovite granite in the deposit show that the mineralization is genetically related to the granite, which has a zircon U-Pb age of 131.5 ± 0.8 Ma, and cassiterite in the deposit has a U-Pb age of 128.0 ± 2.0 Ma (Early Cretaceous). The muscovite granite is high SiO2 (74.18 %∼80.72 %), alkaline (Na2O + K2O 4.64 %∼8.17 %), with A/CNK ratios of 1.19 ∼ 1.52. It is a potassic, peraluminous, highly differentiated S-type granite, formed by partial melting of upper crust, and it experienced significant crystallization differentiation and interaction with F-rich fluid during its evolution. Geochronology and geochemical results on magmatic rocks in northern Jiangxi Province show the Maopengdian deposit belongs to the third stage (135–120 Ma) of magmatic activity in the region, where highly differentiated, reduced S-type granites similar to the Maopengdian muscovite granite are likely to be prospective for Sn mineralization.

Examining fingerprint trace elements in cassiterite: Implications for primary tin deposit exploration

In this study, a machine learning method and a piece of cassiterite trace element composition data were used to find fingerprint trace elements that distinguish different tin (Sn) mineralization types and build tools for exploring primary Sn deposit exploration. The trace element dataset of cassiterite from the granite-related Sn metallogenic system was built using the following two approaches: (1) by analyzing the cassiterite samples from nine Sn deposits in Myanmar using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and (2) collecting published data. The resulting dataset contains 661 records of 12 trace elements in cassiterite from 4 mineralization types: pegmatite, greisen, quartz-vein, and skarn. The spider diagrams of trace elements and the principal component analysis indicate that cassiterite samples from the same one mineralization type are clustered together and have unique geochemical characteristics. Using recursive feature elimination with cross-validation and simulation, tantalum (Ta), niobium (Nb), manganese (Mn), hafnium (Hf), iron (Fe), scandium (Sc) and Sc/Ta, Sc/Hf, and Sc/Mn were selected as the fingerprint elements and ratios, respectively. The cluster distribution in the biplots of the fingerprint elements and ratios indicates that these fingerprints are sensitive to the mineralization type. The distribution in the biplots also reveals that there is an evolutionary sequence of magmatic–hydrothermal fluids from pegmatite to skarn at the cassiterite crystallization environment. This data-driven study improves our understanding of the isomorphism between Sn and ions with similar charge and ionic radii in cassiterite from different hydrothermal environments. The complementary relationships between vanadium (V), Nb, and Ta are also identified. The element V is preferred to form a charge balance pair with Sc in cassiterite from skarn, whereas Ta and Nb are preferred to constitute a charge balance pair in cassiterite from the quartz-vein, pegmatite, and greisen. Our findings demonstrate that trace element compositions of detrital cassiterite grains from stream sediments can be used as an exploration tool to discover concealed primary Sn deposits and to evaluate the economic value based on the grade-tonnage model in the preliminary stage of mineral exploration.

Age, Genesis and Tectonic Setting of the Sayashk Tin Deposit in the East Junggar Region: Constraints from Lu–Hf Isotopes, Zircon U–Pb and Molybdenite Re–Os Dating

The Sayashk tin (Sn) deposit is located within the southern part of the Eastern Junggar orogenic belt in Xinjiang Province and forms part of the Kalamaili alkaline granite belt. There are many Sn polymetallic deposits in the area. To constrain the age, genesis, and tectonic setting of the Sayashk tin deposit in the East Junggar region, we conducted a bulk-rock geochemical analysis of the granite porphyry (SR1) and medium- to fine-grained granite (SR2) hosts of the deposit, LA-ICP-MS zircon U–Pb dating and Lu–Hf isotopic analysis, as well as molybdenite Re–OS dating and combined our results with the metallogenic conditions and other geological characteristics of the deposit. The results show that the Sayashk Sn deposit is indeed spatially, temporally, and genetically closely related to the granite porphyry and medium-fine-grained granite. Both zircon U–Pb ages are 308.2 ± 1.5 Ma and 310.9 ± 1.5 Ma, respectively. The isochron age of molybdenite is 301.4 ± 6.7 Ma, which represents the crystallization age of the granite porphyry and medium-fine-grained granite. Therefore, all of them formed in the late Carboniferous epoch. The medium-fine-grained granites and granite porphyry are characteristically rich in Si and alkali, poor in Ca and Mg, rich in high field-strength elements (HFSE, e.g., Zr, Hf) and Ce, and deficient in Ba, Sr, Eu, P, and Ti. They are typical A-type granites, showing the characteristics of a mixed crustal mantle source. The εHf(t) values of the zircon from the granite porphyry (SR1) range from 10.27 to 16.17 (average 13.71), εHf(t) values of the zircon from the medium-fine-grained granites (SR2) are between 5.72 and 9.21 (average 7.08), and the single model ages (TDM1) and two-stage model ages (TDM2) of the granite porphyry (SR1) fall within the ranges of 319~535 Ma and 339~644 Ma. The single model ages (TDM1) and two-stage model ages (TDM2) of the medium-fine-grained granites (SR2) fall within the ranges of 346~479 Ma and 309~557 Ma. There is little difference between their two-stage model ages and zircon U–Pb ages, indicating that the Sayashk granite may be the product of partial melting of juvenile crustal. Combined with previous research results, the Sayashk Sn deposit formed in a post-collision extensional tectonic setting after the late Carboniferous in the Kalamaili area.

In situ geochemistry and Sr–O isotopic composition of wolframite and scheelite from the Yaogangxian quartz vein-type W(–Sn) deposit, South China

Wolframite and scheelite are primary W–bearing minerals and form in multiple metallogenic stages in quartz-vein type W(–Sn) deposits, recording copious metallogenic information. This study investigates the geochemistry, geochronology and Sr–O isotope of these minerals in the Yaogangxian W(–Sn) deposit, South China, to constrain the metallogenic age and decipher the mineralization process. Three wolframite and scheelite phases were identified in the greisen and quartz-vein type ores with different cathodoluminescence (CL) response, rare-earth element (REE) characteristics, and Sr–O isotopic compositions. The Cassiterite U–Pb dating in the greisen phase yielded a 156.0 ± 0.7 Ma isochron age and a 147.5 ± 0.6 Ma isochron age in the oxide phase, both of which are within error or slightly younger than Jurassic granites. From the early to late stage, the ΣREE contents of scheelite and wolframite decreased sharply, and the REE patterns of the scheelite changed from the LREE-enriched with negative Eu anomalies to HREE-enriched with positive Eu anomalies. The δ18OH2O values of the fluid (8.5 ‰–8.8 ‰) in the greisen phase calculated using the scheelite–H2O fractionation equation are identical to the magmatic–hydrothermal fluid, whereas the δ18OH2O values of the fluid (1.4 ‰–1.6 ‰) in the sulfide phase indicate the fluid mixing with meteoric water. The (87Sr/86Sr)0 ratios of wolframite and scheelite in the quartz-vein type ores range from the 0.74972 to 0.78397, higher than the Jurassic granites ((87Sr/86Sr)0 = 0.71593–0.73188) but lower than the sandstone in the host rock ((87Sr/86Sr)0 = 0.785227–0.813912), indicating an intense fluid-rock interaction. Therefore, although the W(–Sn) mineralization is primarily related to Jurassic granites, fluid mixing and fluid–rock interaction in the quartz-vein type ores might have been a trigger mechanism for W(–Sn) precipitation.

Differentiated enrichment of magnetite in the Jurassic W–Sn and Cu skarn deposits in the Nanling Range (South China) and their ore-forming processes: An example from the Huangshaping deposit

Abundant Jurassic magnetite-rich W–Sn and magnetite-poor Cu skarn deposits were discovered in the Nanling Range of South China. However, their ore-forming processes and the mechanism of differentiated magnetite enrichment are still poorly constrained. The Huangshaping represents a typical skarn deposit in the Nanling Range, which developed both W–Mo–Sn and Cu mineralization systems, providing a good window to address this issue. In the Huangshaping W–Mo–Sn system, abundant magnetite was formed in three generations (Mag-1, Mag-2, and Mag-3). Mag-1 shows core (Mag-1c)-mantle (Mag-1 m)-rim (Mag-1r) texture, with abundant nano-inclusions trapped in the oscillatory-zoned Mag-1 m. Porous Mag-2 replaced Mag-1 along sharp and irregular boundaries, and both Mag-1 and Mag-2 were replaced by cassiterite. Mag-3 occurred along with quartz-bismuthinite veins and also replaced Mag-1. Magnetite-4 (Mag-4) has a homogeneous texture and occurs locally in the Huangshaping Cu system. The mineral assemblage, texture, and geochemistry suggest a hydrothermal origin for all these magnetite types and possible magmatic-hydrothermal pulses in the W-Mo-Sn system. The first magmatic-hydrothermal pulse was likely associated with granite porphyry and formed Mag-1 in a closed system with increasing oxygen fugacity (fO2) and decreasing concentrations of trace elements. The abundant nano-inclusions in Mag-1 m suggest probable local supersaturation of trace elements in the magnetite-fluid interface. The irregular contact, porosities, and lower trace element concentrations (e.g., Mg, Al, Si, Ca, and Mn) of Mag-2 reveal that it may have formed via the dissolution and reprecipitation process (DRP) of Mag-1. This process was possibly controlled by decreasing fO2. The second magmatic-hydrothermal pulse derived from the granite porphyry may have formed Mag-3, evidenced by the increasing temperature, decreasing fO2, and high trace element concentrations (e.g., Mg, Al, Si, Ca, and Mn). In the Cu system, the quartz porphyry-derived ore fluid may have formed Mag-4 under lower temperature and fO2 than in the W–Mo–Sn system. Besides, we suggested that the paucity of magnetite in these Jurassic Cu skarn deposits of the Nanling Range was likely caused by the low Fe concentration in the ore-related magma, genetically associated with the amphibole fractionation during the magma formation. This may respond to the extensional formation environment of Jurassic Cu and W–Sn skarn deposits in the Nanling Range, caused by the asthenosphere upwelling linked to the Paleo-Pacific subduction.

Fabrication and Electrochemical Performance of TiO2–TiN/Sn–SnO2 Composite Films on Ti for LIB Anodes with High Capacity and Excellent Conductivity

AbstractAccording to the requirements for anode materials of safe and high‐capacity lithium‐ion batteries (LIBs), various Sn/TiO2 and SnO2/TiO2 composite materials have been developed, but no reports have yet combined them by a simple fabrication method. Herein, a novel and simple approach is reported for the fabrication of nanoporous TiO2–TiN/Sn–SnO2 composite films by successive Ti anodization and cathodic hybrid electrodeposition of Sn in a nitric acid‐based aqueous solution containing Sn2+ and/or Sn4+ ions. The conductivity of the anodic TiO2–TiN composite films facilitates the simultaneous electrodeposition of metallic Sn and electrophoretic deposition of SnO2 colloids, both on the surface and inside the nanopores of the film. Notably, the nanoporous structure is preserved, which provides a large surface area. The electrodeposition of Sn–SnO2 nanoparticles on the nanoporous TiO2–TiN film significantly improves the charge transfer and conductivity of the composite film and enhances the discharge capacity to up to 2386.1 µAh cm−2 (approximately sixfold higher than that of the bare matrix film).

Tectonic control on the spatial distribution of Sn mineralization in the Gejiu Sn district, China

Late Cretaceous granitic rocks occur in the Gejiu ore district to the east and west of the N-S striking Gejiu Fault, whereas major Sn deposits are only known to occur to the east of the Gejiu Fault. Comparison of the whole-rock chemistry, the apatite trace-element chemistry, and zircon Hf and O isotope data of the various granites demonstrates that fertile granites occur to both sides of the Gejiu fault. The results demonstrate that the c. 83 Ma old granitic intrusions (i) have similar magma sources, which are dominated by metasedimentary rocks that had experienced intense chemical weathering, resulting in reduced melts, (ii) had similar melting conditions, i.e., high temperature biotite dehydration melting, and (iii) in part had experienced large extents of fractional crystallization. The most evolved granites to both sides of the Gejiu Fault have the characteristics typical of tin granites. Therefore, the absence of major deposits to the west of the Gejiu Fault is not due to the absence of fertile granites. The areas to the east and the west of the Gejiu Fault, however, have fundamentally different fault pattern, which indicates different orientation of the stress field to both sides of the Gejiu Fault at the time of the emplacement of the Cretaceous granites. Late Cretaceous dextral movement along the Ailaoshan Fault Zone resulted in a (trans)tensional setting in areas to the east of the Gejiu Fault and in a (trans)pressional setting to the west of that fault. We speculate that the tectonic setting influences the potential for mineralization because the Sn bearing fluids need efficient pathways to transporting metals from the roof zone of the batholith into the wall rocks. In contrast to regional compression, hydraulic fracturing in an overall extensional setting has the potential to develop efficient fluid pathways and, thus, may lead to major ore deposits. To the west of the Gejiu Fault, however, granite intrusions in an overall compressional setting are likely to develop no or only small mineralization.

PREPARATION OF CZTS THIN FILM EMPLOYING RAPID THERMAL PROCESSING METHOD

CZTS thin film was fabricated by sulfurization process of deposited thin films on Mo coated glass substrates. Cu, Zn, and Sn thin film layers were deposited sequentially to form Glass/Mo/CuSn/Zn/Cu. The CuSn layer in the stacked structure was formed by annealing process in the sputtering chamber after sequential deposition of Cu and Sn, respectively. The sulfurization process was performed by rapid thermal processing method (RTP) so as to obtain kesterite CZTS structure. The obtained CZTS thin film was analyzed using several characterization methods such as EDX, XRD, Raman spectroscopy, SEM and PL measurements. The EDX measurements showed that elemental loss was not observed after the annealing process in sulfur atmosphere. The fabricated CZTS thin film showed Cu stoichiometric and Zn rich composition. The XRD pattern of annealed sample revealed formation of kesterite CZTS structure. The Raman spectra of the sample proved formation of kesterite CZTS structure. In addition, some CTS phases were detected in the structure by Raman spectroscopy. Polycrystalline surface microstructure was seen in SEM surface measurement. The room temperature PL measurement exhibited a transition around at 1.39 eV that is very close to band gap of kesterite CZTS structure. Overall, with this study, it has been shown that the CZTS thin film structure can be easily produced using the RTP method with very high heating rate.

Discrepant chemical differentiation and magmatic-hydrothermal evolution of high-silica magmatism associated with Pb–Zn and W mineralization in the Lhasa terrane

High-silica (SiO2 > 70 wt.%) granites (HSGs) are the main source of W, Sn, and rare metals. However, abundant HSGs, temporally, spatially, and genetically associated with Pb–Zn mineralization, in the Lhasa terrane (LT), provided an ideal opportunity to study the key factors responsible for Pb–Zn enrichment, instead of W–Sn enrichment. Here we contribute to this topic through U-Pb dating of zircon and garnet, and whole-rock and Sr–Nd–Hf isotopic geochemistry of ore-related quartz porphyries in the Bangbule deposit and compared these results with published data from large and giant Pb–Zn and W deposits in the LT. The magmatism-alteration-mineralization event in the Bangbule deposit was recorded by robust zircon U–Pb ages of 77.3 ± 0.9 Ma and hydrothermal garnet U–Pb ages of 75.7 ± 4.8 Ma, which is 10–15 Ma earlier than the main Paleocene metallogenic event and the first record of late Cretaceous Pb–Zn polymetallic mineralization in the LT. The late Cretaceous-Paleocene magmatism and mineralization events are a response to the subduction of Neotethyan oceanic lithosphere, which occurred as a result of the collision of the Indian and Asian plates. These HSGs related to Pb–Zn mineralization, with high total-alkalis and low magnesian contents, are enriched in Ba, Th, and Rb, but depleted in Ti, Eu, Sr, and P. They belong to either the S-type, or I-type granites. The Sr–Nd–Hf isotopic compositions of the Pb–Zn mineralized granites demonstrate that they were generated by the partial melting of Proterozoic basement with or without mantle-derived melt input. This was consistent with the postulated source of W enrichment in the LT. The Pb–Zn and W related granites have similar zircon-Ti-saturation temperatures, comparable low whole-rock Fe2O3/FeO ratios, and zircon oxygen fugacity. This indicated that the Pb–Zn–W enrichment in the high-silica magma system could be attributed to a relatively reduced magma. The Pb–Zn related HSGs, abundant quartz and feldspar phenocrysts, and weak fractionation of twin-elements in whole-rock analysis, can be used to reconstruct a model of the magma reservoir. We postulate that these features could be reproduced by silica-rich crystal accumulation in a magma reservoir, with a loss of magmatic fluids. The magma associated with W mineralization exhibited a higher level of differentiation compared to the Pb–Zn related magma; however, different groups of zircon texture with varying rare earth elements and concomitance of rare earth elements tetrad effect and high fractionation of twin-elements in whole-rock are formed by a magmatic-hydrothermal transition in highly evolved system. As the source and oxygen fugacities of the Pb–Zn and W related magmas are similar, the absence of a giant W–Sn deposit in the LT may indicate that parent magmas with a low degree of evolution and magmatic-hydrothermal transition are not conducive to their formation. This implies that the rocks that originated as highly evolved silicate-rich parent magmas, with a high degree of magmatic-hydrothermal alteration, would need to be targeted for W–Sn mineral exploration in the LT. In summary, our results emphasize that variations in chemical differentiation and the evolution of high-silica magmatic-hydrothermal systems can lead to differences in Pb–Zn and W enrichment. This has implications for the evaluation of the mineral potential of high-silica granites and hence their attractiveness as targets for mineral exploration.

Water durability modification of cerium-manganese oxide by tin shell for efficient airborne benzene oxidation

Single or cooperative incorporation of Ce and Sn elements into α-MnO2 parent were tried to update the catalytic benzene oxidation performance, and the successive modification via Ce doping and Sn deposition was demonstrated to be a promising methodology to offer high mineralization and avoid moisture-aroused inactivation. Ce doping caused lattice distortion, increased Mn3+ content to 2.7 times that of the pristine MnO2 and weakened Mn-O bonds due to electron transfer from Ce3+ to lattice oxygen, thus facilizing oxygen vacancy formation. Further, Sn deposition on CeMn substrate induced strong metal support interaction (SMSI) due to the core-shell like structure of Sn@CeMn, which promoted the construction of active oxygen vacancies to an even larger extent (1.2 and 2.5 times that of the CeMn and pristine MnO2, respectively). The thus-formed larger amount of reactive oxygen species rendered the Sn@CeMn simultaneously with high CO2 yield and low CO production. Also benefited from the SMSI effect, the Sn@CeMn’s ability to continuously activate O2 and H2O into reactive oxygen species (e.g.,·OH radicals) was enhanced, which could offset the negativity caused by water vapor, thereby keeping > 95% removal during 5.5 h water switch on/off investigation at 200 °C. Reaction pathways were uncovered with designed experimentations.

The Mushiston Sn deposit in Tajik Tien Shan as the type locality for stannite-cassiterite-hydrostannate mineralization: New mineral chemistry data and genetic constraints

The Mushiston Sn deposit is located in Hercynian South Tien Shan fold and thrust belt on the territory of Tajikistan. Unique features of the deposit include sulphide-dominated composition of the primary ore with stannite being the main ore mineral, and a thick oxidation zone where stannite is replaced by various hydrostannate minerals. Therefore, the Mushiston deposit is a rare example of stannite-cassiterite-hydrostannate mineralization and the type locality where several new hydrostannate minerals such as mushistonite, natanite and vismirnovite were first described. The structure of the deposit is characterized by a series of subvertical, generally NE-trending mineralized veins crosscutting the limbs of the large submeridional anticline composed of Paleozoic sedimentary strata. The primary ore mainly consists of a quartz-stannite group minerals – cassiterite mineral assemblage with other subordinate sulfides and minor sulfosalts. A 200–400 m thick zone of supergene oxidation is developed in the upper part of the deposit. New mineral chemistry data reveal compositional variations of the stannite group minerals, sphalerite and sulfosalts. The chemical compositions of co-existing stannite group minerals and sphalerite indicate extensive mutual substitution between Fe and Zn. The use of stannite-sphalerite geothermometry constrains the temperature for the main stage of the primary ore formation in the range of 257–308 °C. The tetrahedrite geothermometry yields temperatures in the range of 170–200 °C, which is in agreement with geological evidence for the late crystallization of sulfosalts at lower temperatures. The geological and mineralogical features of the Mushiston Sn deposit correspond to the mesothermal hydrothermal vein system mainly developed under intermediate sulfidation conditions. The proposed genetic model for the Mushiston deposit suggests formation of brittle fractures in the thermal aureole above the concealed causative granitoid intrusion, by regional analogue of Permo-Carboniferous age, where magmatic fluids mixed with meteoric water to form the hydrothermal system responsible for deposition of cassiterite-sulfide ore.

Crucial control on magmatic-hydrothermal Sn deposit in the Tengchong block, SW China: Evidence from magma differentiation and zircon geochemistry

Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas, but why most global high silica granites do not bear economic Sn ore grades remains unclear. Two crucial factors controlling magmatic-hydrothermal Sn mineralization, including advanced fractionation and depressurization-induced rapid cooling, were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit, in the Tengchong block, SW China. The Guyong granitic pluton comprises three petrological facies: less evolved biotite syenogranite, evolved alkali granite and leucogranite, and highly evolved facies (the protolith of greisenized granite). Similar crystallization ages (∼77 Ma) and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process. Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high (>87 wt.%) that can only be achieved by a high initial water (≥4 wt.%) content in the parent granitic magma revealed by rhyolite-MELTS calculation. Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas, suppressing the exsolution and transport of hydrothermal fluids. Hence, it must be compensated by the second critical factor: depressurization-induced rapid cooling, reflected by the occurrence of highly metamict zircons in the greisenized granite. The highly metamict feature, indicated by the large full width at half maximum (FWHM) values of zircon ν3(SiO4) peak (>19.5 cm−1), suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment. Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids, interacting with wall rocks and resulting in Sn mineralization.

Temporal Separation of W and Sn Mineralization by Temperature-Controlled Incongruent Melting of a Single Protolith: Evidence from the Wangxianling Area, Nanling Region, South China

Abstract Tungsten and Sn display similar behavior during magmatic processes and are commonly associated spatially and genetically with highly evolved granites. Nonetheless, they typically form separate deposits, even if their associated granites have the same protolith. This separation may be due to the fractionation of the metals at the magmatic-hydrothermal transition or their differential mobility during partial melting of the metasedimentary protolith. If this separation occurred at the magmatic-hydrothermal transition, the ages of the W and Sn deposits would be very similar, whereas if it occurred during partial melting, the deposits are likely to have different ages because of the concentration of the metals in different magma batches and, in extreme cases, during different magmatic events. New age data from the Wangxianling ore field in the western part of the world-class Nanling W-Sn metallogenic province demonstrate that the W and Sn mineralization took place at different times. The W mineralization (219.5 ± 3.4 Ma) is related to Triassic granites (224.9–217.8 Ma), whereas the Sn mineralization is related to granites of Late Jurassic age (154.7 ± 1.1 Ma). This difference in ages rules out fractionation at the magmatic-hydrothermal transition as an explanation for the spatial separation of the W and Sn deposits and implies that the separation was due to differences in the mobility of W and Sn during partial melting. Both suites of granite originated from the partial melting of the same metasedimentary rocks, and both are reduced and highly evolved. The W granites, however, have a lower zircon saturation temperature (~750°C) than the Sn granites (~800°C), which indicates that the magma forming the W granites was mainly the product of muscovite-dehydration melting, whereas that forming the Sn granites was largely the result of biotite-dehydration melting. The different melting paths indicate that W released during muscovite breakdown dissolved in the magma, whereas Sn was sequestered by restite biotite. At the higher melting temperature, the residual W and Sn, released during the subsequent breakdown of biotite, dissolved in the magma. Thus, the magma that generated at low temperature was enriched in W, leading to subsequent W mineralization, whereas the magma that generated at high temperature was enriched in Sn and produced an Sn-mineralized granite. The whole-rock Sr-Nd isotope data for the Triassic W granites plot in the compositional field of the regional basement rocks and are consistent with partial melting of an orogenically thickened crust by internal heating in a collisional setting. In contrast, the Sr-Nd isotope data for the Late Jurassic Sn(-W) granites are displaced toward a mantle composition, likely reflecting contributions from mantle-derived material. Given the emplacement of many of the Late Jurassic Sn(-W) granites close to the Chenzhou-Linwu fault, we propose that this structure was the focus of decompression melting of the mantle and the injection of mantle-derived melts into the crust during the Late Jurassic, which supplied the additional heat for the melting at higher temperature needed to generate magmas enriched in Sn. This model, which is based on differences in the behavior of Sn and W during crustal melting, is potentially applicable to other Sn-W metallogenic provinces where Sn and W deposits are temporally separated.

Effects of ethylenediamine tetrakis(ethoxylate-block-propoxylate) tetrol on tin electrodeposition

Electrodeposition of Tin (Sn) is studied in the presence of ethylenediamine tetrakis(ethoxylate-block-propoxylate) tetrol (ETT). Cyclic voltammetry (CV), chronoamperometry, and chronopotentiometry are conducted to characterize the electrochemical behavior of Sn with the addition of ETT. Several influencing factors such as the ETT concentration, rotation rate, and potential scan rate are systematically investigated, and it is found that ETT suppresses Sn deposition at a certain negative potential range due to a potential dependent adsorption of ETT. This adsorption of ETT is further dependent not only on the empty surface fraction but also the occupied fraction or surface coverage. Moreover, various additives containing different functional groups of ETT are used to determine the key structural component for the inhibition effect.

Genesis of the Tashan porphyry host tin deposit, eastern Guangdong, Southeast China: Constrains from geology, geochronology, and geochemistry

The medium-sized Tashan Sn deposit, mainly hosted in the Tashan granite porphyry, is located in eastern Guangdong, Southeast China. Zircon U–Pb dating of the granite porphyry yielded a concordant age of 138.0 ± 1.1 Ma, which is consistent with the cassiterite U–Pb age of 138.0 ± 2.3 Ma from the Sn ores, indicating a temporal link between the emplacement of granitic pluton and Sn mineralization. The contents of Fe3+, Fe2+, and Mg2+ in biotite, low calculated zircon Ce4+/Ce3+ of 4.4–71.6, low Eu/Eu* ratios of 0.06–0.35, and low whole-rock Fe2O3/FeO of 0.04–0.13 of the granite porphyry reveals its low oxygen fugacity, which may have facilitated the Sn enrichment during magma evolution and played a key role in the Sn mineralization. Low K/Rb (150–175, aver. = 160), Nb/Ta (7.3–8.2, aver. = 7.8), and Zr/Hf (23.2–25.1, aver. = 23.9) values were observed for the granite porphyry, indicating its high fractionation and probable interaction with an aqueous fluid phase to some extent. The reduced and highly fractionated features and high F and Sn contents of the granite porphyry thus indicate it is a typical Sn-fertile granite. The granite porphyry is weakly peraluminous and belongs to high-K calc-alkaline type. The rocks are characterized by high SiO2, K2O + Na2O, F, and Zr + Nb + Ce + Y (360–410 ppm) contents; and 10000 Ga/Al (2.31–3.06) ratios and low CaO, MgO, TiO2, and P2O5 contents; Rb, Cs, Th, and U enrichment; and Ba, Sr, Zr, Ti, and P depletion, exhibiting an A-type affinity. Moreover, the rocks display whole rock initial 87Sr/86Sr values of 0.70927–0.71218, εNd(t) of − 6.5 to − 6.3, and zircon εHf(t) values from − 5.7 to − 1.5 with Mesoproterozoic TDM2 ages for both Nd and Hf isotopes, indicating their formation by partial melting of a crustal source of Mesoproterozoic overall residence ages with minor input of mantle materials. By integrating new and published data on tectonic evolution, we suggest that the granite porphyry and associated Sn mineralization in the Tashan deposit that was formed in a back-arc extensional environment started before ∼ 141 Ma, related to the rollback of the paleo-Pacific Plate.

Trace elements in apatite from Gejiu Sn polymetallic district: Implications for petrogenesis, metallogenesis and exploration

The world-class Gejiu tin polymetallic district is located in southeastern Yunnan Province. Yet, the largest deposits are concentrated in the Masong and Laoka granites in the eastern area of Gejiu. To investigate the factors controlling Sn mineralization among intrusions in the Gejiu area, we collected apatite from eight different intrusions (including gabbro, monzonite, and granite) and determined the fertility indices of Sn deposits through the chemical composition of apatite. Analysis of the redox-sensitive elements in apatite showed that the ore-bearing granites have high Mn and low S content, high Y/∑REE and low La/Sm ratios, extreme negative Eu anomalies, and weak Ce positive anomalies compared to the barren intrusions, indicating that the formation environment of the ore-bearing granites was more reducing. The apatites in ore-bearing intrusions have lower Sr and higher Y contents, which suggests that these intrusions have a higher degree of fractionation than barren intrusions. The apatites in the Masong and Laoka granites have a high F content, which reflects the high F content of magma that contributed to the enrichment of Sn. The decreasing (Sm/Yb)N ratios with stable Sr content imply exsolution of Cl-rich fluids or crystallization of monazite and allanite. The exsolution of Cl-rich fluids can increase Sn solubility in the melt and promote the extraction of Cu from basalt. The apatites in the ore-bearing intrusions have high Li, Mn, Fe, and F contents and extremely low (Eu/Eu*)N ratios (<0.05). These results show that apatite can be used to distinguish Sn deposits from other deposit types and guide the Sn exploration.

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

Zircon mineral chemistry and implications for magmatic-hydrothermal evolution of the granite-hosted Zaaiplaats Sn deposit, Bushveld Large Igneous Province, South Africa

This study presents trace element compositions for zircons from a series of co-genetic granitic rocks of the Lebowa Granite Suite (LGS) that host the Zaaiplaats Sn mine in the northern limb of the Bushveld Large Igneous Province (LIP). In this area, the LGS comprises the coarse-grained Nebo and Bobbejaankop granites, and the fine-grained Lease granite, of which the two latter are variably altered and host Sn mineralisation. Under cathodoluminescence, zircons of the Nebo granite display long prismatic crystals and well-developed internal oscillatory zoning, whereas those of the Bobbejaankop and Lease granites are porous with faint zoning and vermicular to spongy internal textures. Trace element contents of zircons in the Bobbejaankop and Lease granites show significant enrichments in all the trace elements (e.g., Hf, Nb, Ta, U, Th, Ti, and REE) suggesting a hydrothermal origin for the zircons of the Bobbejaankop and Lease granites, that are different to those for the magmatic zircons of the Nebo granite. Moreover, the inclusion-free hydrothermal zircons of the Bobbejaankop and Lease granites point to lower Ti-in-zircon derived crystallisation temperatures (450-600 °C) and oxygen fugacities [as log (ƒO2) values in the range − 20 to −26] than those of the Nebo granite [where T = 570-625 °C and log (ƒO2) values = −19 to −21]. Collectively, the data record an apparent magmatic differentiation from a single magma, showing derivation of the hydrothermal zircons of the Bobbejaankop and Lease granites from a highly-fractionated late-magmatic-hydrothermal fluid enriched in F, Cl and B, as indicated by non-chondritic Y/Ho and Zr/Hf ratios under reducing conditions, as required typically for the formation of the granite-hosted Sn deposits.