Boron isotope variations in tourmaline from hydrothermal ore deposits: A review of controlling factors and insights for mineralizing systems

Trumbull, Robert B.; Codeço, Marta S.; Jiang, Shao‐Yong; Palmer, Martin R.; Slack, John F.

doi:10.1016/j.oregeorev.2020.103682

Cited by 51 publications

(17 citation statements)

References 120 publications

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“…8). This range of δ 11 B values approaches that for tourmaline from massive sulfide deposits (Palmer and Slack 1989) but does not reach the higher values of +20 to +35 ‰ reported for tourmaline from other types of hydrothermal ore deposits such as orogenic gold, iron oxide-copper-gold, and sedimenthosted uranium (Trumbull et al 2020). Although the range of δ 11 B values for most natural reservoirs is relatively well known, problems still remain in identifying the predominant source of boron in tourmalinites as well as in tourmaline from various types of ore deposits.…”

Section: 2 Boroncontrasting

confidence: 64%

“…Although the range of δ 11 B values for most natural reservoirs is relatively well known, problems still remain in identifying the predominant source of boron in tourmalinites as well as in tourmaline from various types of ore deposits. This is a particularly difficult challenge for isotopically light boron, for which tourmaline δ 11 B values in the range of -16 to -4 ‰ may reflect boron derived from several sources, including granitic magmas, marine sediments, or non-marine evaporites and carbonates (Trumbull and Slack 2018;Trumbull et al 2020). Other processes that may affect the boron isotopic composition of tourmaline include the temperature of formation, metamorphic fractionation, fluid/rock ratios, extent of seawater entrainment, and secular variation in seawater δ 11 B values (Palmer and Slack 1989).…”

Section: 2 Boronmentioning

confidence: 99%

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Perspectives on premetamorphic stratabound tourmalinites

Slack¹

2022

J. Geosci.

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Stratabound tourmalinites are metallogenically important rocks that locally show a close spatial association with diverse types of mineralization, especially volcanogenic massive sulfides (VMS) and clastic-dominated (CD) Zn-Pb deposits. These tourmalinite occurrences span the geologic record from Eoarchean to Jurassic. Host lithologies are dominated by clastic metasedimentary rocks but in some areas include metavolcanic rocks, marble, or metaevaporites. Stratabound and stratiform (conformable) tourmalinites commonly display sedimentary structures such as graded beds, cross-beds, and rip-up clasts. In most cases, field and microtextural relationships are consistent with a synsedimentary to early diagenetic introduction of boron as a precursor to tourmaline formation. Whole-rock geochemical data for major, trace, and rare earth elements (REE) provide valuable insights into tourmalinite origins. Al-normalized values relative to those for least-altered host metasedimentary rocks suggest that tourmalinites in proximal settings at or near hydrothermal vent sites characterized by high fluid/rock regimes (e.g., Sullivan Pb-Zn-Ag deposit, Canada) have very different signatures than those in low fluid/rock, distal settings (e.g., Broken Hill Pb-Zn-Ag deposit, Australia). The high fluid/rock regimes at Sullivan show large mass changes of +60 % for Mg and +180 % for Mn, as well as large variations in abundances of light and middle REE. In contrast, tourmalinite formation in low fluid/rock regimes yields minimal Al-normalized changes in major elements, trace elements, and REE. Boron isotope values of tourmalinite-hosted tourmaline vary widely from -26.1 to +27.5 ‰, and are attributed mainly to boron sources (e.g., sediments, evaporites) with generally minor influence from processes such as formational temperature, fluid/rock ratio, and secular variation in seawater δ 11 B values. Laterally extensive stratiform tourmalinites formed mainly by syngenetic or early diagenetic processes on or beneath the seafloor. The syngenetic process is attributed to the interaction of vented B-rich brines with aluminous minerals in sediments, whereas the diagenetic process involves the selective replacement of aluminous sediments by B-rich fluids. Modern examples of tourmalinites, as yet undiscovered, may exist in metalliferous sediments of the Red Sea and the eastern Pacific Ocean, in altered volcaniclastic sediments within active seafloor-hydrothermal systems of the South Pacific, and in hydrothermal mounds and vents associated with mafic sill complexes in extensional basins as in the North Sea and South China Sea. Stratabound tourmalinites that contain base-metal sulfides, high Mn concentrations (>1 wt. % MnO), or positive Eu anomalies can be valuable exploration guides for base-metal sulfide deposits in sedimentary and volcanic terranes.

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Section: 2 Boroncontrasting

confidence: 64%

Section: 2 Boronmentioning

confidence: 99%

Perspectives on premetamorphic stratabound tourmalinites

Slack¹

2022

J. Geosci.

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“…The wide range in the isotopic fractionation of boron in different geological environments makes it possible to constrain the source of boron in hydrothermal systems on the basis of boron isotope data for tourmaline (Marschall and Jiang 2011;Trumbull et al 2020). Tourmaline also exhibits a very high degree of stability after crystallization.…”

Section: Indications For Involvement Of Evaporitic Fluidsmentioning

confidence: 99%

“…12 Histogram of δ 11 B values for analyzed Juomasuo tourmaline and comparison with values of different global boron isotope reservoirs. Reservoirs modified afterTrumbull et al (2020)…”

mentioning

confidence: 99%

Geochemical signatures of mineralizing events in the Juomasuo Au–Co deposit, Kuusamo belt, northeastern Finland

et al. 2021

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The Juomasuo Au–Co deposit, currently classified as an orogenic gold deposit with atypical metal association, is located in the Paleoproterozoic Kuusamo belt in northeastern Finland. The volcano-sedimentary sequence that hosts the deposit was intensely altered, deformed, and metamorphosed to greenschist facies during the 1.93–1.76 Ga Svecofennian orogeny. In this study, we investigate the temporal relationship between Co and Au deposition and the relationship of metal enrichment with protolith composition and alteration mineralogy by utilizing lithogeochemical data and petrographic observations. We also investigate the nature of fluids involved in deposit formation based on sulfide trace element and sulfur isotope LA-ICP-MS data together with tourmaline mineral chemistry and boron isotopes. Classification of original protoliths was made on the basis of geochemically immobile elements; recognized lithologies are metasedimentary rocks, mafic, intermediate-composition, and felsic metavolcanic rocks, and an ultramafic sill. The composition of the host rocks does not control the type or intensity of mineralization. Sulfur isotope values (δ34S − 2.6 to + 7.1‰) and trace element data obtained for pyrite, chalcopyrite, and pyrrhotite indicate that the two geochemically distinct Au–Co and Co ore types formed from fluids of different compositions and origins. A reduced, metamorphic fluid was responsible for deposition of the pyrrhotite-dominant, Co-rich ore, whereas a relatively oxidized fluid deposited the pyrite-dominant Au–Co ore. The main alteration and mineralization stages at Juomasuo are as follows: (1) widespread albitization that predates both types of mineralization; (2) stage 1, Co-rich mineralization associated with chlorite (± biotite ± amphibole) alteration; (3) stage 2, Au–Co mineralization related to sericitization. Crystal-chemical compositions for tourmaline suggest the involvement of evaporite-related fluids in formation of the deposit; boron isotope data also allow for this conclusion. Results of our research indicate that the metal association in the Juomasuo Au–Co deposit was formed by spatially coincident and multiple hydrothermal processes.

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“…Tourmaline is the main boron-bearing mineral in hydrothermal ore deposits formed in different geological settings (Hazarika et al, 2019;Zheng et al, 2019;Daver et al, 2020;Harlaux et al, 2020;Trumbull et al, 2020). Meanwhile, tourmaline has stable physicochemical properties and a negligible element diffusion rate (van Hinsberg et al, 2011a;van Hinsberg et al, 2011b).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal fluid evolution in the Cuonadong Sn–W–Be polymetallic deposit, southern Tibet: indicated by the in–situ element and boron isotope compositions of tourmaline

Xie

Yan²,

Zhang³

et al. 2023

Front. Earth Sci.

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The Cuonadong Sn–W–Be polymetallic deposit in the Himalayan leucogranite belt is a representative hydrothermal deposit. The role of fluid exsolution directly from magma and the fluid reaction with surrounding rocks for ore-forming element enrichment is still controversial. Tourmaline is a significant B-bearing mineral in the hydrothermal deposit, and its geochemical and B isotopic signatures can record the source and evolution of the ore-forming fluid. Two types of hydrothermal tourmaline in the hydrothermal quartz vein (Tur-1) and skarn (Tur-2) were used in this study. Both Tur-1 and Tur-2 have low X-site occupancy and mainly belong to the alkali group. Tur-1 plots in the schorl field, whereas Tur-2 is largely Mg-rich dravite. The B isotope analyses of Tur-1 have δ11B values of −13.7 to −13.2‰, whereas Tur-2 has higher δ11B values of −11.1 to −9.3‰. The distinct contact relationship and geochemical compositions suggest that Tur-1 in the hydrothermal vein was formed from a magmatic-hydrothermal fluid with little influence from surrounding rocks and had a genetic relationship with the Cuonadong leucogranite, whereas Tur-2 in the skarn involved more fluid from surrounding rocks with high δ11B values and strong metasomatic texture. The higher ore-forming element contents in Tur-2 than those in Tur-1 indicate that the reaction between the magmatic exsolution fluid and the surrounding rock is essential for the enrichment and precipitation of ore-forming elements.

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Boron isotope variations in tourmaline from hydrothermal ore deposits: A review of controlling factors and insights for mineralizing systems

Cited by 51 publications

References 120 publications

Perspectives on premetamorphic stratabound tourmalinites

Perspectives on premetamorphic stratabound tourmalinites

Geochemical signatures of mineralizing events in the Juomasuo Au–Co deposit, Kuusamo belt, northeastern Finland

Hydrothermal fluid evolution in the Cuonadong Sn–W–Be polymetallic deposit, southern Tibet: indicated by the in–situ element and boron isotope compositions of tourmaline

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