Fluid mixing as primary trigger for cassiterite deposition: Evidence from in situ δ18O-δ11B analysis of tourmaline from the world-class San Rafael tin (-copper) deposit, Peru

Harlaux, Matthieu; Kouzmanov, Kalin; Gialli, Stefano; Marger, Katharina; Bouvier, Anne‐Sophie; Baumgartner, Lukas P.; Rielli, Andrea; Dini, Andréa; Chauvet, Alain; Kalinaj, Miroslav; Fontboté, Lluı́s

doi:10.1016/j.epsl.2021.116889

Cited by 31 publications

(10 citation statements)

References 49 publications

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“…Mixing magmatic fluids and meteoric water has been proposed as a primary driver to promote metals deposition in Sn(-W) deposits. While mixing induced cooling certainly could play a significant role in this regard (Legros et al 2019;Xiong et al 2019;Liu et al 2020;Harlaux et al 2021), but most samples studied here do not require the involvement of meteoric water, hence our cassiterite oxygen isotope analysis call for an reassessment for this hypothesis.…”

Section: Applications In Sn(-w) Depositsmentioning

confidence: 86%

“…Most Sn(-W) deposits are associated with granites, with ore-forming fluids being magmatic in origin, and then experienced variable degrees of mixing with meteoric water during ore precipitation (Legros et al 2019;Harlaux et al 2021). In addition to constraining temperatures of ore formation, estimating the proportion of meteoric water fluxing is also important to trace fluid evolutionary processes, and to decipher its role in metals deposition.…”

Section: The Binary Mixing Model In Magmatic-hydrothermal Systemsmentioning

confidence: 99%

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Cassiterite oxygen isotopes in magmatic-hydrothermal systems: in situ microanalysis, fractionation factor, and applications

Zhang

et al. 2021

Miner Deposita

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Tin and tungsten are important metals for the industrializing society. Deciphering the origin and evolution of hydrothermal fluids responsible for their formation is critical to underpin genetic models of ore formation. Traditional approaches obtain isotopic information mainly from the bulk analysis of both ore and gangue minerals, or less frequently from in situ analysis of gangue minerals, which either bear inherited complexities and uncertainties or are indirect constraints. Hence directly obtaining isotopic information from ore minerals such as cassiterite by in situ techniques is critical, as this may significantly improve our understanding of fluid evolution and its controls on ore formation. However, this has been hampered by challenges from both analytical and applicational aspects. In this study, we first demonstrate a lack of crystallographic orientation effects during cassiterite ion microprobe oxygen isotope analysis. Along with our newly developed matrix-matched reference material, the Yongde-Cst, which has a recommended δ 18 O value of 1.36 ± 0.16 ‰ (VSMOW) as defined by Gas-Source Isotope Ratio Mass Spectrometry, in situ oxygen isotope analysis of cassiterite now is possible.We further refine the oxygen isotope fractionation (1000 ln α) for quartz-cassiterite by firstprinciples calculations, which is given by the equation of 1.259×10 6 /T 2 + 8.15×10 3 /T -4.72 (T is temperature in kelvin). The 1000 ln α for quartz-cassiterite has a sensitive response to temperature, and makes cassiterite-quartz an excellent mineral pair in oxygen isotope thermometry, as described by the equation of T (℃) = 2427 × (δ 18 Oqtz -δ 18 Ocst) -0.4326 -492.4.Using the well-established 1000 ln α of quartz-water, 1000 ln α of cassiterite-water is derived as 2.941×10 6 /T 2 -11.45×10 3 /T + 4.72 (T in kelvin), which shows a weak response to temperature. This makes cassiterite an ideal mineral from which to derive δ 18 O of fluids as robust temperature estimates are not a prerequisite. We have applied oxygen isotope analysis to cassiterite samples from six Sn(-W) deposits in China. The results show considerable variability in δ 18 O values both within a single deposit and among studied deposits. Combining the δ 18 O of cassiterite samples and the equilibrium oxygen isotope fractionation, we find that the δ 18 O values of ore-forming fluids show a strong magmatic affinity with variable but consistently low degree of involvements of meteoric water. This study demonstrates that in situ oxygen isotope analysis of cassiterite is a promising tool to refine sources of ore-forming fluids, and to decode hydrothermal dynamics controlling tin and tungsten mineralization.

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Section: Applications In Sn(-w) Depositsmentioning

confidence: 86%

Section: The Binary Mixing Model In Magmatic-hydrothermal Systemsmentioning

confidence: 99%

Cassiterite oxygen isotopes in magmatic-hydrothermal systems: in situ microanalysis, fractionation factor, and applications

Zhang

et al. 2021

Miner Deposita

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“…The temperature-dependent tourmaline-fluid B isotope fractionation (Meyer et al 2008) is used to calculate the δ 11 B fluid values. The quartz-tourmaline oxygen isotope thermometer has yielded crystallization temperatures of ~650℃ for disseminated and nodular tourmaline at the magmatic-hydrothermal transition, and ~550℃ for tourmaline as post-magmatic replacements and veins in tin-bearing granites elsewhere (Harlaux et al 2021). These temperatures are adopted for Tur-1 and Tur-2/Tur-4 in this study, respectively (App.4).…”

Section: Source Of the Magma And Ore-forming Fluidsmentioning

confidence: 99%

Fluid-rock interaction and fluid mixing in the large Furong tin deposit, South China: New insights from tourmaline and apatite chemistry and in situ B-Nd-Sr isotope composition

Chen

et al. 2023

American Mineralogist

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The Furong tin deposit (South China) is genetically associated with the multiphase Qitianling batholith that consists of main-phase and minor but more fractionated late-phase granites. Several tourmaline and apatite generations are distinguished. Tourmaline (Tur) variants comprise pre-ore Tur-1 as disseminations and nodules in the late-phase granite, pre-to syn-ore Tur-2 as replacements in nodules and as veins This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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“…Its two isotopes, 10 B and 11 B, partition differently between borate and boric acid, the two dominant species of boron in aqueous solutions 1–5 . Because the proportion of borate and boric acid changes according to the pH of the environment, the 10 B/ 11 B ratio is widely used to investigate processes that involve water, including the weathering process, 6–8 ocean pH changes, 9–11 tectonic processes, 12–14 and ore formation 15–17 . Multi‐collector inductively‐coupled plasma mass spectrometry (MC‐ICP‐MS) permits high throughput of B isotope measurements.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5] Because the proportion of borate and boric acid changes according to the pH of the environment, the 10 B/ 11 B ratio is widely used to investigate processes that involve water, including the weathering process, 6-8 ocean pH changes, 9-11 tectonic processes, 12-14 and ore formation. [15][16][17] Multicollector inductively-coupled plasma mass spectrometry (MC-ICP-MS) permits high throughput of B isotope measurements. However, relatively elevated and persistent instrumental B background between samples, or the B memory effect, remains a common concern.…”

mentioning

confidence: 99%

New insights into the source of the boron memory effect and implications for accurate boron isotope measurements

Cai

Chen

et al. 2023

Rapid Comm Mass Spectrometry

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Rationale:The boron (B) memory effect is a concern for B isotope analysis in inductively-coupled plasma mass spectrometry and a potential cause of poor data comparability between laboratories. It is widely assumed that the memory resides in water droplets on the surface of the spray chamber. However, even without the use of the spray chamber, background subtractions are still required to generate accurate data, therefore additional causes for the memory effect exist, which are investigated here.Methods: Different parts of the mass spectrometer were examined to pinpoint the source of a particularly high B background. After identifying the torch as the source of the background, different parts of the torch were soaked in dilute nitric acid, which was analyzed for B over time.Results: B was leached out of the tip of the outer quartz tube of the torch in a fashion similar to borosilicate glass, which suggests the incorporation of B into the silica structure of the torch at high temperatures. Running 3% nitric acid washes effectively reduces the background. B background compositions change based on the solutions run beforehand, therefore different blank subtraction methods generate systematic differences. A new background subtraction method that utilizes B isotope ratios improved the precision by up to 0.14‰. The addition of a water wash step before sample elution led to smaller eluent volumes and improved matrix matching without causing a B breakthrough.Conclusions: An important part of the B memory derives from the torch glass, which incorporates B from sample solutions at high temperatures. Multiple nitric acid washes, matrix matching, blank subtraction, and standard sample bracketing generated accurate B isotope analyses with background/signal ratios as high as 10%, without the need for hazardous chemicals as washes. B isotope values of two sediment standards that represent average post-Archean continental crust were reported. | INTRODUCTIONBoron (B) is highly soluble in water. Its two isotopes, 10 B and 11 B, partition differently between borate and boric acid, the two dominant species of boron in aqueous solutions. [1][2][3][4][5] Because the proportion of borate and boric acid changes according to the pH of the environment, the 10 B/ 11 B ratio is widely used to investigate processes that involve water, including the weathering process, 6-8 ocean pH changes, 9-11 tectonic processes, 12-14 and ore formation. [15][16][17] Multicollector inductively-coupled plasma mass spectrometry (MC-ICP-MS) permits high throughput of B isotope measurements. However, relatively elevated and persistent instrumental B background between samples, or the B memory effect, remains a common concern. This memory effect is generally attributed to B(OH) 3 vapor from previously nebulized solutions that become entrained in droplets coating the walls of the spray chambers. [18][19][20] The use of demountable

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Fluid mixing as primary trigger for cassiterite deposition: Evidence from in situ δ18O-δ11B analysis of tourmaline from the world-class San Rafael tin (-copper) deposit, Peru

Cited by 31 publications

References 49 publications

Cassiterite oxygen isotopes in magmatic-hydrothermal systems: in situ microanalysis, fractionation factor, and applications

Cassiterite oxygen isotopes in magmatic-hydrothermal systems: in situ microanalysis, fractionation factor, and applications

Fluid-rock interaction and fluid mixing in the large Furong tin deposit, South China: New insights from tourmaline and apatite chemistry and in situ B-Nd-Sr isotope composition

New insights into the source of the boron memory effect and implications for accurate boron isotope measurements

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