Global Sn Isotope Compositions of Cassiterite Identify the Magmatic–Hydrothermal Evolution of Tin Ore Systems

Abstract

Published Sn isotope data along with 150 new analyses of cassiterite and four granite analyses constrain two major tin isotope fractionation steps associated with (1) separation of tin from the magma/orthomagmatic transitional environment and (2) hydrothermal activity. A distinct Sn isotope difference across deposit type, geological host rocks, and time of ore deposit formation demonstrates that the difference in the mean δ¹²⁴Sn value represents the operation of a unified process. The lower Sn isotope values present in both residual igneous rocks and pegmatite suggest that heavier Sn isotopes were extracted from the system during orthomagmatic fluid separation, likely by F ligands with Sn. Rayleigh distillation models this first F ligand-induced fractionation. The subsequent development of the hydrothermal system is characterized by heavier Sn isotope composition proximal to the intrusion, which persists in spite of Sn isotope fractionating towards isotopically lighter Sn during hydrothermal evolution.

1. Introduction

Although a relatively new isotopic technique, to date, approximately 50 papers present Sn isotope data that address fundamental questions in planetary geology, igneous petrology, mineralogy, and archeology. Furthermore, they reveal significant Sn isotopic fractionation that operates at temperatures above approximately 200 °C, and which is beginning to allow for the interpretation of these patterns in rocks, ores, and artifacts.

Presentation of tin isotope data vary because there are 10 isotopes, which can be paired in many ways. For the sake of simplicity, the data are presented here as ‰ per amu and relative to the NIST 3136A standard in the traditional δ¹²⁰Sn and δ¹²⁴Sn values. In this way, the isotopic shifts observed can be seen at the amu level and mass dependence of the samples is verified. Further discussion of data presentation and how the values are calculated is in Wu et al. 2023.

Empirical observation, laboratory experimentation, and thermodynamic bonding arguments have begun to constrain mechanisms by which Sn isotopes fractionate. Many of the papers have focused on constraining planetary geology processes where meteorites yield relatively lower Sn isotope values up to −0.33‰/amu (all values are reported relative to the NIST 3136 tin standard) [1,2,3,4,5]. In this case, high-temperature evaporation has been identified as the cause of fractionation. For terrestrial rocks and ore minerals, it has been demonstrated that the main causes for tin fractionation include melt extraction, redox reactions, evaporation/fluid boiling, and magmatic equilibrium processes [6,7,8,9,10,11,12,13].

Pioneering papers have shown that the widest range of tin isotope fractionation exists in the mineral cassiterite (SnO₂) [6,11,14,15,16,17,18,19,20,21] with ranges of −0.31‰/amu to +0.32‰/amu, whereas most terrestrial rocks exhibit a more limited range between −0.08‰/amu and +0.08‰/amu. None of the papers link mineralization with source rocks, nor do they explore processes that relate hydrothermal systems and source rocks. For instance, Yao et al. [13] show that the oxidation that promotes cassiterite precipitation from a hydrothermal solution causes significant enrichment of the heavier tin isotopes earlier in the petrogenesis of the deposit, such that paragenetically late stannite is composed of the lighter tin isotopes. Correlative evidence through studies of several Chinese tin deposits [11,18,21] showed that the earlier-formed cassiterite has overall higher Sn isotope values than subsequent generations precipitated upon further cooling.

Here, we propose that Sn isotopes constrain the relationship between source rocks and ore mineralization, based on a global comparison of tin isotope compositions of cassiterite from tin granites/porphyries, pegmatites, greisens, veins, and skarns. The approach provides insight into the similarities and differences of physiochemical reactions occurring during the magmatic–hydrothermal transition. Tin granites are mostly, but not exclusively, peraluminous S-type magmas typically generated in the mid- to lower-crust of back-arc regions through the partial melting of dominantly metasedimentary source rocks [22] that differentiate and crystallize over a range of depths within the upper continental crust. Several classification schemes have shown the differences in the character of mineralization and silicate mineral alteration assemblage that are related to the tectonic environment and emplacement depth of the felsic source rocks. Most tin mineralization is of hydrothermal nature and occurs disseminated or fracture-controlled in greisen zones and in stockworks/veins within the causative granite or its country rocks, or as skarns within reactive Ca-rich host rocks. Cassiterite in pegmatites may crystallize from the melt or precipitate in the transitional magmatic–hydrothermal stage of the fluid-saturated melt system.

For the sake of simplicity, tin mineralization can be divided into two realms: (1) an orthomagmatic realm, which involves magmatic to magmatic–hydrothermal transitional systems like pegmatites that form in deeper environments, and (2) hydrothermal-dominated greisens, vein/stockwork systems, and skarns, i.e., shallower environments (Figure 1). The designation of tin deposit types in this scheme highlights an important similarity. In both instances, a cooling granitoid exsolves an aqueous fluid phase induced by pressure release (“first boiling”) or isobaric crystallization of anhydrous minerals (“second boiling”), which results in high-temperature hydrothermal alteration and mineralization. However, given that fluid saturation is pressure-dependent, the production of a magmatic–hydrothermal fluid occurs at higher temperature and at an earlier stage of crystallization in shallower deposits [22]. Thus, tin remains within the silicious magmatic phase of pegmatites or deep granitoids longer, allowing for magmatic cassiterite formation, while cassiterite growth in shallower systems is predominantly hydrothermal in nature. Therefore, from a mass balance standpoint, comparing the tin isotope compositions in each of the tin reservoirs will illuminate potential processes associated with tin mineralization.

Tin ore deposits are much more restricted in distribution compared to metals like copper, although both form magmatic–hydrothermal systems. The need for highly evolved, fractionated, reduced, felsic magmatism for tin mineralization is distinctly different than the conditions needed to form magmatic–hydrothermal copper deposits that are typically associated with widespread arc or post-collisional oxic magmatism and associated high-temperature hydrothermal processes. Thus, comparing the ore metal isotope compositions of Cu and Sn provides a further opportunity to identify unique processes associated with mineralization of Sn.

2. Sampling, Tin Deposits, and Methods

Cassiterite samples were selected from the two general deposit types described above and are organized as such in Table 1 and Table 2. The majority of samples were obtained from the American Museum of Natural History in New York City. The use of museum specimens allowed for acquisition of materials from areas where mining activity removed all mineralization and provides reliable location information for each sample. A smaller subset of cassiterite samples originated from field collecting within different deposits by the authors of this paper. This approach ensures robust sample location and deposit association for all materials.

Two hundred and seventy-two cassiterite results are presented in Table 1, Table 2 and Table 3, which includes one hundred and fifty-nine unpublished results. All major known tin deposits/districts on Earth are represented in the sixty deposits of the dataset. The dataset includes cassiterite from every continent except Antarctica, and from deposits spanning diverse mineralization styles of tin (e.g., greisens, veins, stockworks, disseminations), as well as spanning the Archean through the Cenozoic.

The data distribution for the two general types of tin deposits (deep versus intermediate to shallower mineralization) are pegmatites (deep) with 80 cassiterite samples from 10 deposits, veins (intermediate) with 131 cassiterite samples from 31 deposits, and porphyry/skarns (intermediate) with 76 cassiterite samples from 11 deposits. The intermediate–shallow deposits are lumped together as a means for comparison; for instance, skarns can form at various depths and are simply treated as the hydrothermal part of the binary classification presented here [22,23,24].

To explore the details of tin fractionation within one system, a subset of 14 cassiterites and 3 rock samples are examined from Geiju, a highly studied tin mineralization system that has been mined since the Bronze Age in China (Table 3). The cassiterite samples span the ore district and were chosen at different distances (both vertical and horizontal, in the order of Km) from the source intrusion and two different mineralization styles, both skarn and veined types of cassiterite. Studies of the textures and ore genesis are found in [25,26,27]. The rock samples were chosen from the host intrusion and lacked disseminated cassiterite. Comparison of the ores and rocks samples provided a broader glimpse into the mineralization process and how tin isotopes vary over one large system.

Chalcopyrite (CuFeS₂), the main ore mineral of copper that forms in high-temperature mineralization systems is used here for comparison with the Sn system. Igneous chalcopyrite from magmatic systems originated from layered mafic intrusions, disseminated in igneous rocks and komatiites [28,29,30,31,32,33,34,35,36,37,38]. Chalcopyrite from hydrothermal systems originated from porphyry copper deposits, epithermal deposits, and volcanogenic massive sulfides [39,40,41,42,43,44,45,46,47,48,49,50,51,52,53]. All Cu isotopic data presented here are taken from the literature and are presented relative to the NIST 976 isotope standard.

Sample preparation and measurement of the tin isotopes for cassiterite followed the method and protocols established in [20]. For the two rock samples, separation protocols using AG and Eichrom Tru Spec resins [2,5,20] were used. The data were collected over a twelve-year period on four ICP-MS multicollectors: the Isoprobe at the University of Arizona and the Neptune plus at Rutgers UniversityWashington State University, and the Pennsylvania State University. All samples were measured at low resolution, had on-peak blank subtraction, and had a mass bias corrected value with exponential law through the NIST Sb standard 3102, which were subsequently corrected with standard–sample–standard using NIST Sn standard 3161a. The instruments measured in both wet (at the University of Arizona, Rutgers University, and Pennsylvania State University) and dry plasma (at Rutgers University and Washington State University) modes as summarized in Table 4.

The data in Table 1, Table 2 and Table 3 provide the traditional per mil values for δ¹²⁴Sn and δ¹²⁰Sn relative to the NIST 3161a tin standard, and all data taken from the literature are compared to this standard. In this manner, mass dependence of the data becomes evident. However, throughout this paper and in the data table, the data are presented as ‰ per amu (for instance, the traditional presentation of δ¹²⁴Sn = x‰, which is normalized here to δSn = x‰/8 amu; notation further described in [11]). This normalization of the data allows for comparison of the tin isotope data with the copper isotope data.

As a means to establish QA/QC assurances of the data, several in-house standards were measured in different matrices found in Table 4. The cassiterite, metal, and bronze samples represent materials that have had full procedural repeats performed on different instruments throughout the past 6 years. The cassiterite and metal produce a 2σ = 0.11 (which is a slightly smaller error than reported in 20) in comparison with the 2σ = 0.21 for the bronze materials. The larger variations seen in the bronzes reflect sample heterogeneity.

3. Results

To relate the global trends seen in the tin isotopes, mean tin isotope values are compared across general ore genesis and deposit types. Data are presented as violin plots to display ranges and the overlapping nature of the data. The global dataset shows that cassiterite from magmatic/orthomagmatic origin has lower tin isotope values than in hydrothermal systems (Figure 2A). When subdivided into individual deposit types, cassiterite from pegmatite has lower mean values in comparison to mean values from porphyry systems, skarn, and veined systems (Figure 2B). Portraying the data in these two different filters shows that regardless of how the data are organized, the hydrothermal ores (porphyry, skarn, and vein systems) are higher than bulk silicate earth and magmatic ores (pegmatites) are lower.

For Geiju, the cassiterites have higher tin isotope values than the tin isotope values of the source rocks (Figure 3). When compared to published data [54,55,56,57] for tin isotope values in rocks, the three samples from Geiju are significantly lower. Tin isotope values for cassiterite appear to have a spatial pattern, where cassiterites closest to the source intrusion have higher tin isotope values.

4. Discussion

4.1. Across Deposit Type Global Comparisons

The formation of tin deposits requires that the magma experiences extended fractionation during cooling and crystallization to produce highly evolved late-stage granites. Crustal contamination and fractional crystallization can lead to the exsolution of a high-temperature fluid enriched in incompatible elements that possesses high concentrations of tin and other rare elements. Here, the tin isotope composition of the cassiterite records physiochemical reactions in both the magma and the hydrothermal systems associated with mineralization. As seen in Figure 2 and Figure 3, there are distinct differences in the tin isotope composition of igneous cassiterite hosted in granitic rocks versus cassiterite in the hydrothermal system. Importantly, this difference occurs in cassiterite across large spans of time, geography, geological host rock, and associated wall-rock alteration. In other words, neither geological timeframe nor geological host environment relates to the recorded difference. Therefore, the tin isotopic differences illustrated here reflect a global process that acted across all types of tin mineralization.

In a general sense, a two-stage process occurs during the formation of these deposits. The exsolution of the hydrothermal fluid from the magma occurs first, referred to as orthomagmatic, followed by a hydrothermal system that cools post-exsolution. From the perspective of tin, the metal concentration of the magma decreases as tin enriches in the hydrothermal solution that is exsolved. During this process, tin travels in the exsolved fluid as a ligand bound to chlorine and/or fluorine. Many thermodynamic and mineralogical works have debated how tin is complexed and what leads to its ultimate precipitation of cassiterite [58,59,60,61,62,63,64]. The majority of these studies suggest that tin was in a reduced form both during melt evolution and in the hydrothermal system [65,66].

Recently, Sun et al. [9] demonstrated that the Sn-F and Sn-Cl complexes favor the higher mass tin isotope due to bonding considerations. The F ligands lead to a significantly larger degree of tin isotope fractionation for reduced tin in comparison to Cl (ΔSn_F-residue = +0.14‰/amu at 400 °C for F in comparison to ΔSn_Cl-residue = +0.014‰/amu at 400 °C for Cl). Given the large isotopic differences among the orthomagmatic and hydrothermal cassiterite in Figure 3A, Cl ligands alone cannot account for the Sn isotope variations at high temperature; Sn-F ligands must have incorporated heavy tin during the fluid exsolution step from the magma leaving the residual rocks/pegmatites with a lighter tin isotope reservoir. Importantly, the ore deposits analyzed in this contribution have been studied in great detail to have different mixtures of the F and Cl ligands involved during mineralization and here we do not intend to solely point to one ligand, rather that they operate in a similar manner with regard to Sn isotope fractionation.

To model this behavior, we use Rayleigh distillation with fractionation factors (α_SnF-magma = 1.001, applied to a starting magma with bulk silicate earth value of 0.02‰) to match the mean Sn isotope value of pegmatite cassiterite. We use the d¹²⁴Sn so that a larger range of isotope values is seen in the model presented and it provides easier graphical representation of the data. As there are more steps that could fractionate tin in the hydrothermal system, we focus on modelling the Sn isotope mean value of the pegmatite to demonstrate the first step needed to yield lower pegmatite tin isotope values. Figure 4 illustrates the tin isotopic evolution of a magma that releases Sn-F into the fluid phase. Depending on the amount of Sn remaining in the magma (f value in the distillation model), the Sn isotope values span the range of all cassiterite samples measured. However, the formation of cassiterite is associated with a fractionation factor that favors the heavier tin isotopes. Therefore, in order to generate a mean value of −0.22‰, approximately 90% of the total tin would have to be partitioned into the liquid from the magmatic fluid and the remaining melt would have an Sn isotope value of −2.2‰. Assuming that the majority of the tin resides in the cassiterite precipitated in the magma, the Rayleigh distillation model predicts 90% or more tin will precipitate to form cassiterite at −0.22‰, the mean tin isotope value of pegmatites. The exercise demonstrates that reasonable amounts of tin can partition into the different reservoirs and generate Sn isotope values measured in cassiterite from pegmatites. Equally interesting, lower cassiterite values predicted with the model indicate that less total tin needs to be extracted from the source intrusion. Therefore, the mean values recorded in pegmatite cassiterite in one system may indicate total tin associated with pegmatite mineralization and be used to assess the potential for tin in associated hydrothermal systems.

The heavier tin isotopes in the hydrothermal fluid, with tin still in the reduced form, generate a ‘higher’ starting tin isotope composition of the hydrothermal system. The nearly identical mean values for the shallow and deeply formed cassiterite demonstrate the uniformity of this fractionation step in deep and shallow tin mineralization systems. Figure 2B teases out the differences among the vein, skarn, and porphyry hydrothermal cassiterite variants and shows the same mean values for each. An oxidation step to form cassiterite will occur in both the residue and product (hydrothermal) systems; thus, pointing to this mechanism as the sole cause for the higher values in the hydrothermal system is non-ideal. This is because the fractionation factor for the oxidation step is twice that of the Sn-F complexes; however, the total mass of tin precipitated during mineralization will control the Sn isotope value of the cassiterite. Assuming Rayleigh distillation operates with tin oxidation fractionation factors at 1.003 [9,67], similarities of the orthomagmatic and hydrothermal cassiterite ranges displays that mechanisms in the second step of Sn isotope fractionation operate in a similar fashion.

The mean tin isotope composition in both reservoirs will be controlled by the amount of tin residing in each reservoir, assuming constant fractionation factors operate within a Rayleigh distillation model. Distillation models predict that specific amounts of tin partition into each reservoir, which constrains the tin isotope compositions of the cassiterite that is formed (x-axis of Figure 4, the variable is commonly designated as f). In the extreme case, where all of the tin is extracted into the hydrothermal fluid, the source rock and the mineralization value would be identical. The fact the means in these two reservoirs are different when comparing the entire cassiterite dataset demonstrates that different proportions of tin reside in the magmatic and hydrothermal products. Modelling the amount of tin within the crystallized source granite and tin in the hydrothermal system for each of these systems is beyond the scope of presentation. However, the tin isotopic differences between magmatic and hydrothermal systems point to the fact that not all Sn is extracted during fluid exsolution. Of further interest is the fact that the mean values of the vein-hosted and porphyry tin deposits are nearly identical, which could indicate similar proportional tin distribution among the residue and products.

Webster et al. [68] documented that F, along with Cl, and Sn may be degassed from tin granite liquids. Thus, the larger isotopic range that is present in the shallower cassiterite could reflect evaporation-induced tin isotope fractionation. The experimental studies of [69] show that evaporation-induced fractionation happens across a diverse set of natural geologic environments. The vapor phase fractionation factor is on the same order, to slightly larger than that resulting from SnF ligand formation. Therefore, the largest range of tin isotope values would result with the evaporation mechanism included.

4.2. Intra-Deposit Comparison of the Ore and Source Rock

Sn isotopic characteristics of the Geiju ore deposits (Tangziao, Gaosong, and Laochang) and their source granite is provided below to further demonstrate the two-step fractionation of Sn in ore systems. The Geiju ore field occurs in southern China with mineralization associated with S-type granites of Late Cretaceous age [70,71,72,73,74]. Multiple deposits of tin are mined at different distances from the magmatic source, as seen in Figure 5, exhibiting three styles of tin mineralization (skarn, veins, and stratabound cassiterite). Here, we focus on the ores that occurred close to the granite–skarn contact, and the granite source rocks.

Mirroring the relationship between the orthomagmatic and hydrothermal cassiterite deposition, the skarn cassiterite samples have higher values than the source rocks from which they were derived at Geiju. The relationship strengthens the hypothesis of the first step of fractionation via F-ligand-bound Sn. If tin fractionation only occurred in the hydrothermal system during precipitation of cassiterite, the tin isotope composition of the residual granite should be similar to other igneous rocks as seen in Figure 3B. That is, the mean values of the cassiterite and granite should be nearly identical in terms of tin isotope composition. Given the large variation between cassiterite and source granite, and the fact that this granite has a lighter Sn isotope composition than all other measured igneous rocks identifies that a fractionating step must have occurred in the orthomagmatic environment.

Modeling the data with Rayleigh distillation using a SnF ligand α value for the fractionating step with the rocks and ores is slightly more complicated. This complexity is seen in the difference between the mean values of the Geiju granite and cassiterite (δSn = 0.1 per mil/amu) as significantly larger than worldwide pegmatite and hydrothermal cassiterite (δSn = 0.06 per mil/amu). The most obvious observation that could explain this difference is a sampling bias when comparing a significantly smaller dataset from Geiju. Equally noteworthy is the fact that all of the cassiterite sampled from Geiju is associated with Sn-bearing garnet assemblages, and none of the pure sulfide-associated cassiterite were sampled. This is important due to the fact that late-stage sulfide-rich fluids precipitate stannite, which is known to have lower Sn isotope values than cassiterite [13,75]. Therefore, the lack of data from the late-stage cassiterite may have skewed the mean difference to larger values because this lower-Sn isotope value reservoir is not considered. These challenges, combined with the potential fractionating factors associated with multiple potential tin-bearing mineral phases in the igneous rocks, make modeling the igneous rock Sn isotope composition non-robust given our current understanding of Sn isotope fractionation and the available data.

Even with the potential sampling bias, a general spatial pattern (Figure 5B) emerges where the highest values are found closest to the granite contact with the limestone and lower values are found at higher elevations. In fact, the lower values found on the granite contact correlate with the edge of the mineralized systems. The Sn isotope values indicate the hydrothermal system where the lower to higher values change vector to the center of the ore deposit. The modest sampling size aside, the data demonstrate the vector preserved in the Sn isotope compositions of cassiterite that was imprinted during hydrothermal activity.

4.3. Comparison with Cu Isotope Compositions of Ores

The formation of tin deposits requires a rather limited range of geological environments. In contrast, copper deposits can form in a variety of tectonic environments, associated igneous lithologies, and range of temperatures. A comparison of the metal isotope composition of the main Cu minerals demonstrates that the higher-temperature processes require multiple fractionation steps of tin in comparison to copper deposits, which do not require multiple magmatic steps to form.

Figure 6 shows the copper isotope difference of magmatic copper versus hydrothermal copper deposits. Note that the degree of isotopic fractionation for copper is significantly larger than tin, as is expected given that copper is a lighter element, and so would have predictably more isotopic separation, even at high temperatures. In addition, note that the copper isotope composition of both hydrothermal and magmatic copper overlap broadly, that the mean values are statistically indistinguishable, and that they correspond to bulk silicate Earth values. Thus, regardless of the mineralizing environment, the vast majority of copper transfers from the source silicate magma to the ore fluid, be it hydrothermal or immiscible sulfide melt [76].

In contrast, the mean tin isotope values for cassiterite in both the source rocks and the products of mineralization are different from the bulk silicate Earth values. Furthermore, the orthomagmatic and hydrothermal ores bracket the bulk silicate Earth value, hydrothermal cassiterite above and orthomagmatic cassiterite below. The same relationship is true of the specific case of Geiju with the hydrothermal ores compared to their tin granitic source rocks. This indicates that a ubiquitous fractionation step occurs within the magma or in the magma–hydrothermal separation stage.

5. Conclusions

The tin isotope composition in ores presented here demonstrate that a two-stage fractionation of tin isotopes occurs during the metallogenesis of these deposits. A comparison of tin to copper isotopes in metal deposits further amplifies this two-stage process in tin metallogenesis. This comparative approach of different tin deposits coupled with comparison to copper isotope results allows for a general physical process associated with tin metal deposits to be identified. It provides a tin isotopic framework to test as the ore metal and associated rock dataset expands.

Author Contributions

R.M. led the scientific team and was part of idea generation, drafting paper, preparing and measuring samples. W.P. was part of idea generation, drafting paper, preparing and measuring samples. J.Y., Y.C., J.M. and M.S. were part of drafting paper, figure generation, sample acquisition, and field assistance. F.G. was part of drafting paper and providing samples. L.G. aided in measuring and technique development with instrumentation, data interpretation and drafting the paper. F.T. was part of drafting the paper, idea generation, and providing simples. D.K. and J.S. provided samples, help in drafting paper, and idea generation. B.L. provided samples, help in drafting paper and idea generation. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

The data provided are in the tables presented in the document.

Acknowledgments

We appreciate the comments from six different reviewers for this document.

Conflicts of Interest

The authors have no conflicts of interest.

Footnotes

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Figures and Tables

Figure 1. General cartoon model of tin mineralization style with depth which portrays the two-step fractionation of tin during deposit formation with F ligand induced fractionation at depth and redox controls on fractionation in shallow regions.

Figure 2. Tin isotope compositions of the products and residues of tin mineralization. Grey bar indicates bulk silicate earth values from the literature. (A) Compares the different types of cassiterite from orthomagmatic versus hydrothermal cassiterite. The mean values and total number of cassiterite samples are labeled beneath the violins. (B) Violin plot that shows the hydrothermal deposit type veins, porphyries, and skarns in comparison to pegmatites.

Figure 2. Tin isotope compositions of the products and residues of tin mineralization. Grey bar indicates bulk silicate earth values from the literature. (A) Compares the different types of cassiterite from orthomagmatic versus hydrothermal cassiterite. The mean values and total number of cassiterite samples are labeled beneath the violins. (B) Violin plot that shows the hydrothermal deposit type veins, porphyries, and skarns in comparison to pegmatites.

Figure 3. (A) Violin plot of skarn mineralization cassiterite and the source rocks from Geiju showing lower Sn isotope values in residual rocks. (B) Box and whisker plot that compares the tin isotope composition of known terrestrial igneous rocks (mostly USGS rock standards) and the ‘residual’ or source rocks from Geiju are significantly lower.

Figure 3. (A) Violin plot of skarn mineralization cassiterite and the source rocks from Geiju showing lower Sn isotope values in residual rocks. (B) Box and whisker plot that compares the tin isotope composition of known terrestrial igneous rocks (mostly USGS rock standards) and the ‘residual’ or source rocks from Geiju are significantly lower.

Figure 4. Rayleigh distillation model for mean pegmatite compositions. Peg. Cass = pegmatite cassiterite and the melt (grey circles) is the residual melt pre-pegmatite formation. Large grey rectangle indicates mean Sn isotope composition of pegmatite cassiterite. The model demonstrates that to generate cassiterite, values derived from a fluid during SnF ligand transport separated about 90% of the tin budget is required. The model also suggests that tin isotope values less than −0.22 require less total tin extraction from the magma.

Figure 5. (A) Location map of Geiju. (B) E-W cross section of the three different deposit types sampled with red values from Tangziao, blue values from Gaosong, and orange value from Laochang. Note the general pattern of higher values proximal to the intrusion which demonstrates the potential to use tin isotopes in cassiterite as a vector tool for hydrothermal activity.

Figure 5. (A) Location map of Geiju. (B) E-W cross section of the three different deposit types sampled with red values from Tangziao, blue values from Gaosong, and orange value from Laochang. Note the general pattern of higher values proximal to the intrusion which demonstrates the potential to use tin isotopes in cassiterite as a vector tool for hydrothermal activity.

Figure 6. Copper isotope composition of chalcopyrite from magmatic and hydrothermal systems that show no difference in mean values, which is different from what is seen with tin isotope values in ore-grade cassiterite. Gray bar indicates bulk silicate earth value from [77,78,79,80,81].

Table 1

Cassiterite samples from pegmatites across the world with Sn isotope values.

Study #	Country	Province	Locality	Per mil/amu	δ120Sn	δ124Sn	Ore Age (MA)	Ore Type	Citation
AFG 01	Afghanistan	Laghman Province		−0.013	0.00	−0.11	30	Pegmatite	This contribution
AFG 02	Afghanistan		Badakhshan	0.072	0.32	0.58	30	Pegmatite	This contribution
AFG 03	Afghanistan		Badakhshan	0.036	0.18	0.29	30	Pegmatite	This contribution
AUS 02	Australia	New South Wales	Elsmore	−0.011	−0.04	−0.09	253	Pegmatite	[10]
AUS 04	Australia	New South Wales	Elsmore	0.014	0.09	0.116	253	Pegmatite	[10]
AUS 14	Australia	Western Australia	Wodgina	0.075	0.32	0.60	2850	Pegmatite	This contribution
AUS 15	Australia	Queensland	Stanthorpe	−0.101	−0.49	−0.81	240	Pegmatite	This contribution
AUS 16	Australia	Tasmania		−0.091	−0.40	−0.73		Pegmatite	This contribution
AUS 06	Australia	New South Wales	Euriowie	−0.056	−0.18	−0.44	1580	Pegmatite	This contribution
BRA 01	Brazil	Minas Gerais	Telirio pegmatite, Linopolis	−0.118	−0.49	−0.94	2120	Pegmatite	This contribution
BRA 02	Brazil	Minas Gerais	Sao Joao del Rei	−0.049	−0.22	−0.39	2120	Pegmatite	This contribution
BRA 03	Brazil	Paraiba	Pedras Pretas	−0.051	−0.21	−0.41	2120	Pegmatite	This contribution
BRA 04	Brazil	Minas Gerais	Linopolis	0.031	0.11	0.25	2120	Pegmatite	This contribution
CON 01	Congo	Manono		−0.028	−0.12	−0.22	940	Pegmatite	This contribution
NAM 01	Namibia	Otjimbojo		0.070	0.27	0.56	550	Pegmatite	This contribution
NAM 02	Namibia	Uis		0.012	0.05	0.10	500	Pegmatite	This contribution
PAK 03	Pakistan			−0.006	−0.03	−0.05	30	Pegmatite	This contribution
PAK 04	Pakistan	Skardu		−0.049	−0.10	−0.39	30	Pegmatite	This contribution
RWA 01	Rwanda	Gatumba		0.027	0.11	0.21	1000	Pegmatite	This contribution
SPA 04	Spain	Galicia	Corunna	−0.047	−0.20	−0.38		Pegmatite	This contribution
SWE 01	Sweden	Skellefte	Varutrask	−0.036	−0.19	−0.29	1782	Pegmatite	This contribution
UGA 01	Uganda	Ankole	Mwirassondo	−0.065	−0.36	−0.52	1000	Pegmatite	This contribution
UGA 02	Uganda	Ankole	Mwirassondo	0.021	0.04	0.17	1000	Pegmatite	This contribution
USA 01	U.S.A.	South Dakota	Etta	−0.147	−0.60	−1.18	1715	Pegmatite	[13]
USA 02	U.S.A.	South Dakota	Ingersoll	0.015	0.04	0.12	1715	Pegmatite	[13]
USA 03	U.S.A.	South Dakota	Etta	−0.142	−0.61	−1.14	1715	Pegmatite	[13]
USA 04	U.S.A.	South Dakota	Etta	−0.040	−0.19	−0.32	1715	Pegmatite	[13]
USA 05	U.S.A.	South Dakota	Black Hills	−0.003	−0.02	−0.02	1715	Pegmatite	[13]
USA 06	U.S.A.	South Dakota	Black Hills	−0.011	−0.04	−0.09	1715	Pegmatite	[13]
USA 07	U.S.A.	South Dakota	Etta	−0.137	−0.57	−1.10	1715	Pegmatite	[13]
USA 08	U.S.A.	South Dakota	Etta	−0.072	−0.32	−0.57	1715	Pegmatite	[13]
USA 23	U.S.A.	Maine	Poland (Havey Peg)	−0.006	0.00	−0.05	260	Pegmatite	This contribution
USA 24	U.S.A.	Maine	Poland (Havey Peg)	−0.006	−0.05	−0.05	260	Pegmatite	This contribution
USA 25	U.S.A.	Maine	Greenwood	−0.036	−0.13	−0.29	260	Pegmatite	This contribution
USA 26	U.S.A.	Maine	Mt Mica	−0.081	−0.39	−0.65	260	Pegmatite	This contribution
USA 28	U.S.A.	Maine	Winslow	0.019	0.09	0.15	260	Pegmatite	This contribution
USA 29	U.S.A.	Washington	Silver Hill Mine	0.030	0.17	0.24	49	Pegmatite	This contribution
USA 30	U.S.A.	Washington	Silver Hill Mine	0.012	0.08	0.09	49	Pegmatite	This contribution
USA 31	U.S.A.	North Carolina	Charlotte	−0.048	−0.21	−0.38	375	Pegmatite	This contribution
USA 32	U.S.A.	North Carolina		−0.072	−0.22	−0.57	375	Pegmatite	This contribution
USA 33	U.S.A.	South Carolina	Gaffney	0.061	0.30	0.49	375	Pegmatite	This contribution
USA 34	U.S.A.	North Carolina		−0.071	−0.16	−0.56		Pegmatite	This contribution
ZIM 01	Zimbabwe	Matabeleland North	Kamativi	−0.043	−0.17	−0.34	1030	Pegmatite	This contribution
ZIM 02	Zimbabwe	Matabeleland North	Kamativi	−0.053	−0.20	−0.42	1030	Pegmatite	This contribution
ZIM 04	Zimbabwe	Matabeleland North	Kamativi	−0.122	−0.55	−0.98	1030	Pegmatite	This contribution
ZIM 05	Zimbabwe	Matabeleland North	Kamativi	−0.054	−0.20	−0.43	1030	Pegmatite	This contribution
ZIM 07	Zimbabwe	Matabeleland North	Kamativi	0.010	0.01	0.08	1030	Pegmatite	This contribution
ZIM 09	Zimbabwe	Matabeleland North	Kamativi	−0.054	−0.18	−0.43	1030	Pegmatite	This contribution
ZIM 10	Zimbabwe	Matabeleland North	Kamativi	−0.124	−0.44	−0.99	1030	Pegmatite	This contribution
ZIM 11	Zimbabwe	Matabeleland North	Kamativi	−0.079	−0.36	−0.63	1030	Pegmatite	This contribution
ZIM 12	Zimbabwe	Matabeleland North	Kamativi	0.011	−0.01	0.09	1030	Pegmatite	This contribution
ZIM 13	Zimbabwe	Matabeleland North	Kamativi	−0.068	−0.18	−0.55	1030	Pegmatite	This contribution
ZIM 14	Zimbabwe	Matabeleland North	Kamativi	−0.047	−0.24	−0.38	1030	Pegmatite	This contribution
ZIM 15	Zimbabwe	Matabeleland North	Kamativi	−0.016	−0.06	−0.13	1030	Pegmatite	This contribution
ZIM 16	Zimbabwe	Matabeleland North	Kamativi	−0.096	−0.41	−0.77	1030	Pegmatite	This contribution
ZIM 18	Zimbabwe	Matabeleland North	Kamativi	−0.115	−0.49	−0.92	1030	Pegmatite	This contribution
ZIM 19	Zimbabwe	Matabeleland North	Kamativi	−0.045	−0.18	−0.36	1030	Pegmatite	This contribution
ZIM 20	Zimbabwe	Matabeleland North	Kamativi	−0.007	−0.03	−0.06	1030	Pegmatite	This contribution
ZIM 21	Zimbabwe	Matabeleland North	Kamativi	0.021	0.01	0.17	1030	Pegmatite	This contribution
ZIM 23	Zimbabwe	Matabeleland North	Kamativi	−0.134	−0.61	−1.07	1030	Pegmatite	This contribution
ZIM 25	Zimbabwe	Masvingo	Bikita	−0.140	−0.64	−1.12	2600	Pegmatite	This contribution
ZIM 26	Zimbabwe	Masvingo	Bikita	0.013	0.20	0.11	2600	Pegmatite	This contribution
ZIM 27	Zimbabwe	Masvingo	Bikita	0.052	0.27	0.42	2600	Pegmatite	This contribution
ZIM 28	Zimbabwe	Masvingo	Bikita	−0.120	−0.49	−0.96	2600	Pegmatite	This contribution
ZIM 29	Zimbabwe	Masvingo	Bikita	−0.147	−0.59	−1.17	2600	Pegmatite	This contribution
ZIM 30	Zimbabwe	Masvingo	Bikita	−0.156	−0.67	−1.25	2600	Pegmatite	This contribution
ZIM 31	Zimbabwe	Masvingo	Bikita	−0.132	−0.52	−1.05	2600	Pegmatite	This contribution
ZIM 32	Zimbabwe	Masvingo	Bikita	−0.301	−1.21	−2.40	2600	Pegmatite	This contribution
ZIM 33	Zimbabwe	Mashonaland East	Mutoko	−0.090	−0.36	−0.72	2600	Pegmatite	This contribution
ZIM 34	Zimbabwe	Mashonaland East	Mutoko	−0.070	−0.30	−0.56	2600	Pegmatite	This contribution
ZIM 35	Zimbabwe	Mashonaland East	Mutoko	−0.063	−0.24	−0.51	2600	Pegmatite	This contribution
PAK 01	Pakistan	Gilgit	Baltistan	0.033	0.12	0.26	30	Pegmatite	This contribution
PAK 02	Pakistan	Gilgit	Baltistan	0.035	0.11	0.28	30	Pegmatite	This contribution
SOM 01	Somalia			−0.144	−0.70	−1.15	530	Pegmatite	This contribution
NAM 03	Namibia		Kransberg	−0.008	−0.08	−0.06		Pegmatite	This contribution
NAM 04	Namibia	Arandis		0.053	0.21	0.42		Pegmatite	This contribution
NAM 05	Namibia	Brandberg West		0.112	0.51	0.89		Pegmatite	This contribution
NIG 01	Nigeria	Jos Plateau		0.011	−0.06	0.09	200	Pegmatite	This contribution
AUS 06	Australia	New South Wales	Euriowie	−0.056	−0.18	−0.44	1580	Pegmatite	This contribution

Table 2

Cassiterite samples from shallower vein dominate systems across the world with Sn isotope values.

Study #	Country	Province	Locality	Per mil/amu	δ120Sn	δ124Sn	Ore Age (MA)	Ore Type	Citation
ARG 01	Argentina	Vil Achay		−0.017	−0.06	−0.14	335	Greisen	This contribution
AUS 11	Australia	New South Wales	Butchart	0.009	0.02	0.07	250	Greisen	This contribution
AUS 01	Australia	New South Wales	Elsmore	−0.010	−0.01	−0.08	253	Greisen	This contribution
AUS 03	Australia	New South Wales	Elsmore	−0.001	0.01	−0.01	253	Greisen	This contribution
AUS 13	Australia	New South Wales	Elsmore	0.014	0.07	0.11	253	Greisen	This contribution
AUS 07	Australia	New South Wales	Tingha	−0.110	−0.53	−0.88	250	Vein	This contribution
AUS 12	Australia	New South Wales	Tingha	0.009	0.06	0.07	250	Vein	This contribution
AUS 10	Australia	New South Wales	Vegetable creek	0.065	0.28	0.52	250	Greisen	This contribution
AUS 05	Australia	Tasmania		0.043	0.28	0.34	250	Greisen	This contribution
AUS 08	Australia	New South Wales		−0.008	−0.02	−0.06	250	Greisen	This contribution
AUS 09	Australia	New South Wales		0.009	0.06	0.07	250	Greisen	This contribution
BOL 13	Bolivia	La Paz	Chojlla	0.018	0.08	0.14	220	Vein	This contribution
BRA 05	Brazil	Igarape Preto		0.056	0.19	0.45	1590	Greisen	This contribution
CZR 01	Czech Republic	Bohemia	Cinovec	0.101	0.43	0.81	320	Greisen	[13]
CZR 02	Czech Republic	Bohemia	Cinovec	0.060	0.26	0.48	320	Greisen	[13]
CZR 03	Czech Republic	Bohemia	Cinovec	0.014	0.02	0.11	320	Greisen	[13]
CZR 05	Czech Republic	Bohemia	Krupka	0.025	0.07	0.20	320	Greisen	[13]
CZR 06	Czech Republic	Bohemia	Horni Slavkov	0.045	0.24	0.36	320	Greisen	[13]
CZR 07	Czech Republic	Bohemia	Horni Slavkov	−0.014	−0.10	−0.11	320	Greisen	[13]
CZR 08	Czech Republic	Bohemia	Horni Slavkov	0.016	0.07	0.13	320	Greisen	[13]
CZR 09	Czech Republic	Bohemia	Krupka	0.122	0.51	0.97	320	Greisen	[13]
CZR 10	Czech Republic	Bohemia	Krasno	0.026	0.11	0.21	320	Greisen	[13]
CZR 11	Czech Republic	Bohemia	Krupka	0.140	0.60	1.12	320	Greisen	[13]
CZR 12	Czech Republic	Bohemia	Krupka	0.136	0.56	1.09	320	Greisen	[13]
CZR 13	Czech Republic	Bohemia	Krupka	0.139	0.57	1.11	320	Greisen	[13]
CZR 14	Czech Republic	Bohemia	Krupka	0.133	0.58	1.07	320	Greisen	[13]
CZR 15	Czech Republic	Bohemia	Krasno	0.043	0.17	0.34	320	Greisen	[13]
CZR 16	Czech Republic	Bohemia	Cinovec	0.002	0.03	0.01	320	Greisen	[13]
CZR 17	Czech Republic	Bohemia	Cinovec	0.113	0.48	0.90	320	Greisen	[13]
CZR 18	Czech Republic	Bohemia	Krupka	0.135	0.58	1.08	320	Greisen	[13]
CZR 19	Czech Republic	Bohemia	Krupka	0.128	0.56	1.02	320	Greisen	[13]
CZR 20	Czech Republic	Bohemia	Krasno	−0.013	−0.05	−0.10	320	Greisen	[13]
CZR 21	Czech Republic	Bohemia	Horni Slavkov	0.124	0.53	0.99	320	Greisen	[13]
CZR 22	Czech Republic	Bohemia	Horni Slavkov	0.046	0.22	0.37	320	Greisen	[13]
CZR 23	Czech Republic	Bohemia	Cinovec	−0.015	−0.02	−0.12	320	Greisen	[19]
CZR 24	Czech Republic	Bohemia	Krasno	−0.009	−0.08	−0.07	320	Greisen	[19]
CZR 25	Czech Republic	Bohemia	Krupka	0.153	0.69	1.23	320	Greisen	[19]
CZR 26	Czech Republic	Bohemia	Cinovec	0.063	0.28	0.50	320	Greisen	[19]
CZR 27	Czech Republic	Bohemia	Horni Slavkov	−0.007	−0.04	−0.05	320	Greisen	[19]
CZR 28	Czech Republic	Bohemia	Horni Slavkov	0.029	0.13	0.23	320	Greisen	[19]
CZR 29	Czech Republic	Bohemia	Krasno	−0.022	−0.02	−0.18	320	Greisen	[19]
CZR 30	Czech Republic	Bohemia	Krupka	0.113	0.39	0.90	320	Greisen	[19]
CZR 31	Czech Republic	Bohemia	Krupka	0.094	0.39	0.75	320	Greisen	[19]
CZR 32	Czech Republic	Bohemia	Krupka	0.096	0.46	0.77	320	Greisen	[19]
CZR 33	Czech Republic	Bohemia	Cinovec	0.114	0.51	0.91	320	Greisen	[19]
CZR 34	Czech Republic	Bohemia	Horni Slavkov	−0.002	0.01	−0.02	320	Greisen	[19]
CZR 36	Czech Republic	Bohemia	Horni Slavkov	−0.003	0.00	−0.03	320	Greisen	[19]
CZR 37	Czech Republic	Bohemia	Krupka	−0.046	−0.17	−0.37	320	Greisen	[19]
CZR 38	Czech Republic	Bohemia	Krupka	0.159	0.70	1.27	320	Greisen	[19]
CZR 39	Czech Republic	Bohemia	Krupka	0.055	0.26	0.44	320	Greisen	[19]
CZR 40	Czech Republic	Bohemia	Hrenecna	−0.088	−0.47	−0.70	320	Greisen	[19]
CZR 41	Czech Republic	Bohemia	Hrenecna	0.033	0.09	0.27	320	Greisen	[19]
EGY 01	Egypt	Abu Dabbab		0.063	0.26	0.50	640	Greisen	This contribution
ENG 01	England	Cornwall		0.137	0.52	1.09	280	Greisen	[13]
ENG 02	England	Cornwall		0.150	0.67	1.20	280	Greisen	[13]
ENG 03	England	Cornwall		0.094	0.39	0.75	280	Greisen	[13]
ENG 04	England	Cornwall		0.085	0.28	0.68	280	Greisen	[13]
ENG 06	England	Cornwall		−0.104	−0.31	−0.83	280	Greisen	[13]
ENG 08	England	Cornwall		0.142	0.57	1.13	280	Greisen	[13]
ENG 09	England	Cornwall		0.102	0.42	0.82	280	Greisen	[13]
ENG 10	England	Cornwall		0.067	0.25	0.54	280	Greisen	[13]
ENG 11	England	Cornwall		0.070	0.30	0.56	280	Greisen	[13]
ENG 12	England	Cornwall		−0.063	−0.24	−0.50	280	Greisen	[13]
ENG 13	England	Cornwall	St Agnes	0.100	0.43	0.80	280	Greisen	[13]
ENG 14	England	Cornwall	St Just	0.101	0.44	0.81	280	Greisen	[13]
ENG 15	England	Cornwall	St Agnes	0.109	0.47	0.87	280	Greisen	[13]
ENG 17	England	Cornwall		0.151	0.70	1.20	280	Greisen	[19]
ENG 18	England	Cornwall	Hemerdon Bal, Plympton	0.108	0.41	0.87	280	Greisen	[19]
FRA 01	France	Brittany		−0.042	−0.18	−0.33	303	Greisen	This contribution
FRA 02	France	Loire		−0.001	−0.02	−0.01	303	Greisen	This contribution
FRA 03	France	Limousin	Montebras	0.090	0.38	0.72	310	Greisen	This contribution
FRA 04	France	Rhone−alpes		−0.022	−0.04	−0.18	310	Greisen	This contribution
FRA 05	France	Brittany	La Villeder	0.008	−0.03	0.06	303	Greisen	This contribution
GER 01	Germany	Germany		0.050	0.21	0.40	320	Greisen	This contribution
GER 02	Germany	Altenberg	Altenberg	0.058	0.25	0.46	320	Greisen	[19]
GER 03	Germany	Ehrenfriedersdorf		0.108	0.44	0.87	320	Greisen	[19]
GER 04	Germany	Ehrenfriedersdorf		0.043	0.21	0.34	320	Greisen	[19]
GER 05	Germany	Sauberg		0.010	0.01	0.08	320	Greisen	[19]
GER 06	Germany	Altenberg	Altenberg	0.032	0.11	0.25	320	Greisen	[19]
GER 07	Germany	Sadisdorf		0.058	0.26	0.46	320	Greisen	This contribution
JAP 01	Japan	Honshu	Takayama	0.031	0.13	0.25		Vein	This contribution
JAP 02	Japan	Honshu	Takayama	0.071	0.19	0.57		Vein	This contribution
JAP 03	Japan	Honshu	Takayama	0.057	0.22	0.46		Vein	This contribution
MAL 01	Malaysia	Panang		0.099	0.41	0.79	240	Greisen	This contribution
MAL 02	Malaysia	Penang	Chenderjang	0.060	0.23	0.48	240	Greisen	This contribution
MAL 04	Malaysia	Johor	Pelepah Kanan	0.050	0.18	0.40	240	Greisen	This contribution
POR 01	Portugal	Panasquiera		−0.080	−0.31	−0.64	295	Greisen	This contribution
POR 02	Portugal	Panasquiera		0.030	0.10	0.24	295	Greisen	This contribution
POR 03	Portugal	Panasquiera		0.072	0.28	0.58	295	Greisen	This contribution
POR 04	Portugal	Panasquiera		0.062	0.21	0.50	295	Greisen	This contribution
POR 05	Portugal	Panasquiera		0.090	0.35	0.72	295	Greisen	This contribution
POR 06	Portugal	Panasquiera		0.056	0.23	0.45	295	Greisen	This contribution
POR 07	Portugal	Panasquiera		0.032	0.11	0.26	295	Greisen	This contribution
POR 08	Portugal	Oporto	Valongo	−0.012	−0.06	−0.10		Vein	This contribution
RUS 01	Russia	Merekski		0.115	0.47	0.92	86	Greisen	This contribution
RUS 02	Russia	Merekski		0.103	0.44	0.82	86	Greisen	This contribution
RUS 03	Russia	Siberia	Onon	0.081	0.31	0.65		Greisen	This contribution
RWA 02	Rwanda	Rutongo		0.024	0.14	0.19	1000	Vein	This contribution
SAF 01	South Africa	North Transvaal	North Transvaal	0.003	−0.03	0.02	2050	Greisen	This contribution
SAF 02	South Africa	Limpopo	Leeuwpoort	0.136	0.55	1.09	2050	Exogranitic	This contribution
SAF 03	South Africa	Limpopo	Zaaiplaats	0.111	0.51	0.89	2050	Greisen	This contribution
SAF 04	South Africa	Limpopo	Zaaiplaats	0.142	0.56	1.13	2050	Greisen	This contribution
SAF 05	South Africa	Limpopo	Zaaiplaats	0.166	0.72	1.33	2050	Greisen	This contribution
SAF 06	South Africa	Limpopo	Rooiberg	0.135	0.54	1.08	2050	Exogranitic	This contribution
SAF 07	South Africa	Limpopo	Rooiberg	0.057	0.30	0.46	2050	Exogranitic	This contribution
SAF 08	South Africa	Limpopo	Rooiberg	0.085	0.30	0.68	2050	Exogranitic	This contribution
SAF 09	South Africa	Limpopo	Rooiberg	0.059	0.15	0.47	2050	Exogranitic	This contribution
SAF 10	South Africa	Limpopo	Rooiberg	0.109	0.38	0.88	2050	Exogranitic	This contribution
SAF 11	South Africa	Limpopo	Rooiberg	0.142	0.62	1.14	2050	Exogranitic	This contribution
SAF 12	South Africa	Limpopo	Rooiberg	0.006	0.07	0.05	2050	Exogranitic	This contribution
SAF 13	South Africa	Limpopo	Rooiberg	−0.006	0.01	−0.05	2050	Exogranitic	This contribution
SAF 14	South Africa	Limpopo	Rooiberg	0.074	0.30	0.60	2050	Exogranitic	This contribution
SER 01	Serbia	Bukulja	Bukulja	−0.008	−0.04	−0.07	20	Greisen	This contribution
SER 02	Serbia	Bukulja	Bukulja	0.028	0.11	0.22	20	Greisen	[19]
SER 03	Serbia	Bukulja	Bukulja	0.013	0.07	0.10	20	Greisen	[19]
SER 04	Serbia	Bukulja	Bukulja	0.031	0.13	0.25	20	Greisen	[19]
SER 05	Serbia	Cer	Cernica	0.059	0.24	0.47	16	Greisen	[19]
SER 06	Serbia	Cer	Cernica	0.052	0.20	0.42	16	Greisen	[19]
SER 07	Serbia	Cer	Milinska	0.068	0.19	0.55	16	Greisen	[19]
SER 08	Serbia	Cer	Milinska	0.060	0.15	0.48	16	Greisen	[19]
SER 09	Serbia	Cer	Milinska	0.063	0.18	0.50	16	Greisen	[19]
SER 10	Serbia	Cer	Milinska	0.079	0.34	0.63	16	Greisen	[19]
SER 11	Serbia	Cer	Milinska	0.100	0.41	0.80	16	Greisen	[19]
SER 12	Serbia	Cer	Milinska	0.079	0.29	0.63	16	Greisen	[19]
SER 13	Serbia	Cer	Milinska	0.034	0.14	0.27	16	Greisen	[19]
SER 14	Serbia	Cer	Milinska	0.063	0.25	0.51	16	Greisen	[19]
SER 15	Serbia	Cer	Milinska	0.032	0.15	0.26	16	Greisen	[19]
SER 16	Serbia	Cer	Milinska	0.058	0.24	0.46	16	Greisen	[19]
SER 17	Serbia	Cer	Milinska	0.072	0.32	0.58	16	Greisen	[19]
SPA 01	Spain	Galicia	Penouta Mine	−0.025	−0.07	−0.20	295	Greisen	[19]
SPA 02	Spain	Galicia	Penouta Mine	−0.046	−0.17	−0.37	295	Greisen	This contribution
SPA 03	Spain	Galicia	Penouta Mine	−0.045	−0.14	−0.36	295	Greisen	This contribution
SPA 05	Spain	Salamanca	Golpejas	0.039	0.15	0.31		Granite	This contribution
SPA 07	Spain	Galicia	San Finx	0.035	0.12	0.28		Vein	This contribution
SPA 08	Spain	Caceres	La Parilla	0.011	0.05	0.09		Vein	This contribution
SPA 09	Spain	Salamanca	Golpejas	0.066	0.29	0.53		Granite	This contribution
SPA 11	Spain	Galicia	Penouta Mine	−0.048	−0.14	−0.38	295	Granite	This contribution
SPA 14	Spain	Ourense	Penouta Mine	−0.025	−0.12	−0.20	295	Greisen	This contribution
SPA 15	Spain	Ourense	Penouta Mine	−0.039	−0.14	−0.31	295	Greisen	This contribution
SPA 16	Spain	Ourense	Penouta Mine	−0.034	−0.11	−0.27	295	Greisen	This contribution
USA 35	U.S.A.	Virginia	Irish Creek	0.086	0.41	0.69	637	Greisen	This contribution
USA 27	U.S.A.	Maine	Norway	0.072	0.30	0.58	260	Greisen	This contribution
BOL 14	Bolivia	La Paz	Chojlla	0.021	0.10	0.17	220	Porphyry	This contribution
BOL 15	Bolivia	La Paz	Viloco	−0.090	−0.35	−0.72	24	Porphyry	This contribution
BOL 01	Bolivia	La Paz	Viloco Mine	−0.082	−0.36	−0.66	24	Porphyry	This contribution
BOL 02	Bolivia	La Paz	Viloco Mine	−0.046	−0.19	−0.37	24	Porphyry	This contribution
BOL 03	Bolivia	La Paz	Viloco Mine	0.087	0.38	0.70	24	Porphyry	This contribution
BOL 04	Bolivia	La Paz	Viloco Mine	0.162	0.68	1.30	24	Porphyry	This contribution
BOL 05	Bolivia	La Paz	Viloco Mine	0.084	0.36	0.67	24	Porphyry	This contribution
BOL 11	Bolivia	Ororu	Huanuni	0.110	0.42	0.88	24	Porphyry	This contribution
BOL 12	Bolivia	Ororu	Poopo	0.111	0.49	0.89	24	Porphyry	This contribution
BOL 06	Bolivia	Oruro	Avicaya	0.011	0.06	0.08	24	Porphyry	[13]
BOL 09	Bolivia	Potosi	Huayoco	0.031	0.14	0.25	24	Volcanic	This contribution
BOL 08	Bolivia	Potosi	Lavisa−ocuri	0.113	0.47	0.90	24	Volcanic	This contribution
BOL 16	Bolivia	Potosi	Llallagua	0.088	0.39	0.70	24	Porphyry	[13]
BOL 17	Bolivia	Potosi	Llallagua	0.089	0.38	0.71	24	Porphyry	[13]
BOL 07	Bolivia	Potosi		−0.074	−0.32	−0.60	24	Porphyry	[13]
BOL 18	Bolivia	Potosi		0.041	0.20	0.33	24	Porphyry	[13]
BOL 19	Bolivia	Potosi		0.100	0.40	0.80	24	Porphyry	[13]
BOL 20	Bolivia	Potosi		0.111	0.48	0.89	24	Porphyry	[13]
BOL 21	Bolivia	Potosi		0.072	0.31	0.58	24	Porphyry	[13]
BOL 22	Bolivia	Potosi		0.050	0.21	0.40	24	Porphyry	[13]
MEX 01	Mexico	Durango		−0.039	−0.16	−0.31	30	Volcanic	[10]
MEX 02	Mexico	Durango		0.080	0.36	0.64	30	Volcanic	[10]
MEX 03	Mexico	Durango		−0.125	−0.54	−1.00	30	Volcanic	[10]
MEX 04	Mexico	Durango		0.001	0.01	0.01	30	Volcanic	[10]
MEX 05	Mexico	Durango		−0.046	−0.16	−0.37	30	Volcanic	[10]
MEX 06	Mexico	Durango		0.028	0.05	0.22	30	Volcanic	[10]
MEX 07	Mexico	Durango		−0.108	−0.48	−0.86	30	Volcanic	[10]
MEX 08	Mexico	Durango		0.001	−0.06	0.01	30	Volcanic	[10]
MEX 09	Mexico	Guanajuato	Santin Mine	0.148	0.57	1.18	30	Volcanic	This contribution
MEX 10	Mexico	Guanajuato	Santin Mine	0.173	0.71	1.38	30	Volcanic	This contribution
MEX 11	Mexico	Guanajuato		0.204	0.88	1.63	30	Volcanic	This contribution
MEX 12	Mexico	Guanajuato		0.027	0.14	0.22	30	Volcanic	This contribution
MEX 13	Mexico	Guanajuato		0.049	0.27	0.39	30	Volcanic	This contribution
POR 09	Portugal	Neves Corvo		0.097	0.33	0.77	360	VMS	This contribution
SPA 06	Portugal	Pyrite Belt	Neves Corvo	−0.139	−0.58	−1.11	360	VMS	This contribution
USA 16	U.S.A.	Alaska	Buck Creek	0.081	0.30	0.65	80	Skarn	This contribution
USA 17	U.S.A.	Alaska	Buck Creek	0.061	0.27	0.49	80	Skarn	This contribution
USA 19	U.S.A.	Alaska	Buck Creek	0.115	0.47	0.92	80	Skarn	This contribution
USA 09	U.S.A.	New Mexico	Taylor Creek	−0.106	−0.46	−0.85	28	Volcanic	[10]
USA 10	U.S.A.	New Mexico	Taylor Creek	0.102	0.40	0.81	28	Volcanic	[10]
USA 12	U.S.A.	New Mexico	Taylor Creek	−0.147	−0.59	−1.18	28	Volcanic	[10]
USA 13	U.S.A.	New Mexico	Taylor Creek	−0.099	−0.40	−0.79	28	Volcanic	[10]
USA 14	U.S.A.	New Mexico	Taylor Creek	−0.050	−0.17	−0.40	28	Volcanic	[10]
USA 20	U.S.A.	New Mexico	Taylor Creek	−0.154	−0.57	−1.23	28	Volcanic	This contribution
USA 21	U.S.A.	New Mexico	Taylor Creek	−0.001	0.01	−0.01	28	Volcanic	This contribution
USA 22	U.S.A.	New Mexico	Taylor Creek	0.012	0.08	0.10	28	Volcanic	This contribution
USA 36	U.S.A.	New Mexico	Taylor Creek	0.042	0.25	0.34	28	Volcanic	[10]
USA 37	U.S.A.	New Mexico	Taylor Creek	0.008	0.09	0.06	28	Volcanic	[10]
USA 15	U.S.A.	Alaska		−0.069	−0.29	−0.55		Skarn

Table 3

Cassiterite and granite Sn isotope values from the Geiju District presented in this work.

Study #	Collection #	Country	Province	Locality	Per mil/amu	δ120Sn	δ124Sn	Ore Age (MA)	Ore Type
G1	P18-12	China	Gejui-Tangziao	Cass-Sulf Zone in Granite	0.143	0.63	1.15	77	Skarn
G2	P18-12	China	Gejui-Tangziao	Cass-Sulf Zone in Granite	0.117	0.49	0.94	77	Skarn
G3	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	0.239	1.11	1.91	77	Skarn
G4	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	0.187	0.79	1.50	77	Skarn
G7	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	0.096	0.41	0.77	77	Skarn
G8	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	−0.092	−0.40	−0.74	77	Skarn
G9	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	0.105	0.47	0.84	77	Skarn
G10	P18-12	China	Gejui-Laochang	Cass-Sulf Zone	0.146	0.56	1.17	77	Skarn
G11	P18-12	China	Gejui-Gaosong	Cass-Sulf Zone	−0.104	−0.47	−0.83	77	Skarn
G12	P18-12	China	Gejui-Gaosong	Cass-Sulf Zone	0.032	0.11	0.25	77	Skarn
G13	P18-12	China	Gejui-Gaosong	Cass-Sulf Zone	0.062	0.21	0.50	77	Skarn
G14	P18-12	China	Gejui-Gaosong	Cass-Sulf Zone	0.084	0.33	0.67	77	Skarn
G15	P18-12	China	Gejui-Gaosong	Stratabound Cass-Sulf	0.102	0.45	0.82	77	Vein
GJ174	P18-05	China	Gejui-Gaosong	Tangziao	−0.100	−0.47	−0.80	77	Rock
GJ175	P18-05	China	Gejui-Gaosong	Tangziao	−0.090	−0.29	−0.72	77	Rock
GJ 161	P18-06	China	Gejui-Gaosong	Tangziao	−0.054	−0.43	−0.63	77	Rock

Table 4

Sn isotope values of in-house standards measured on an Isoprobe at the University of Arizona and a Neptune Plus at Rutgers University and Washington State University. The instrument inlet systems were different where both dry and wet plasma modes were tested. Instruments were in low resolution mode in all locations.

	Matrix	Per mil/amu	δ120Sn	δ124Sn	Date	Location	Instrument	Plasma
CZ 07	Cassiterite	−0.013	−0.02	−0.10	June 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.014	−0.01	−0.11	June 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.014	−0.10	−0.11	June 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.001	−0.05	−0.01	July 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.016	−0.09	−0.13	July 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.018	0.00	−0.14	July 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.016	−0.01	−0.13	July 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.003	0.00	−0.02	July 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.012	−0.04	−0.09	August 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	0.006	0.04	0.05	August 2018	PSU	Neptune Plus	Wet
CZ 07	Cassiterite	−0.013	−0.11	−0.10	August 2016	Arizona	Isoprobe	Wet
CZ 07	Cassiterite	−0.008	0.02	−0.06	April 2019	Rutgers	Neptune Plus	Dry
metal	Metal	0.071	0.28	0.57	Jan 2018	Arizona	Isoprobe	Wet
metal	Metal	0.071	0.32	0.57	April 2019	Rutgers	Neptune Plus	Dry
metal	Metal	0.074	0.34	0.59	Nov 2019	Rutgers	Neptune Plus	Wet
metal	Metal	0.066	0.29	0.53	Nov 2019	Rutgers	Neptune Plus	Wet
metal	Metal	0.076	0.32	0.61	Aug 2019	Rutgers	Neptune Plus	Dry
metal	Metal	0.077	0.29	0.61	Jan 2020	Rutgers	Neptune Plus	Wet
metal	Metal	0.079	0.39	0.63	July 2018	PSU	Neptune Plus	Wet
metal	Metal	0.068	0.29	0.54	Dec 2021	WSU	Neptune Plus	Dry
metal	Metal	0.070	0.29	0.56	Aug 2021	WSU	Neptune Plus	Dry
metal	Metal	0.065	0.26	0.52	April 2022	Rutgers	Neptune Plus	Dry
metal	Metal	0.049	0.20	0.39	Oct 2022	Rutgers	Neptune Plus	Dry
LO2	Bronze	0.143	0.53	1.14	Nov 2019	Rutgers	Neptune Plus	Dry
LO2	Bronze	0.120	0.50	0.96	Jan 2020	Rutgers	Neptune Plus	Dry
LO2	Bronze	0.149	0.63	1.19	Nov 2019	Rutgers	Neptune Plus	Dry
LO2	Bronze	0.123	0.54	0.98	April 2019	Rutgers	Neptune Plus	Dry
LO2	Bronze	0.110	0.44	0.88	Dec 2021	WSU	Neptune Plus	Dry
Zr 01	Bronze	−0.239	−1.01	−1.91	January 2017	Arizona	Isoprobe	Wet
Zr 01	Bronze	−0.208	−0.87	−1.67	Aug 2019	Rutgers	Neptune Plus	Dry
Zr 01	Bronze	−0.207	−0.86	−1.66	Aug 2019	Rutgers	Neptune Plus	Dry
Zr 1	Bronze	−0.208	−0.88	−1.66	Jan 2020	Rutgers	Neptune Plus	Wet

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