The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

Henry, Darrell J.; Dutrow, Bárbara L.

doi:10.3749/canmin.49.1.41

Cited by 57 publications

(16 citation statements)

References 79 publications

(61 reference statements)

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“…The three investigated tourmalines from the Königsalm pegmatite display a negative correlation between the X-site vacancies and the content of [4] Al (R 2 ¼ 0.957). Tourmalines with higher X-site vacancies (magnesiofoitite, foitite) have almost no Al at the T site (Table 4), which suggests formation temperatures ,450 C (Henry & Dutrow, 1996). This would be in agreement with a proposed late hydrothermal origin (200-300 C) of magnesiofoitite and foitite (Hawthorne et al, 1999;Selway et al, 1999;Novák et al, 2004).…”

supporting

confidence: 66%

“…The composition of tourmaline is dependent on the temperature and pressure as well as the chemical composition of the magmatic or metamorphic environment where the tourmaline formed (e.g., Henry & Dutrow, 1996;Ertl et al, 2010a and b). Therefore the composition bears information that is essential to resolve many petrological questions.…”

Section: Introductionmentioning

confidence: 99%

“…A. Ertl et al temperature when F is available for incorporation (Henry & Dutrow, 1996, 2011. The three investigated tourmalines from the Königsalm pegmatite display a negative correlation between the X-site vacancies and the content of [4] Al (R 2 ¼ 0.957).…”

mentioning

confidence: 99%

“…We assume that temperature is also an important factor for the F incorporation in the tourmaline structure during crystallisation in low-to medium-pressure conditions. However, because of an increasing component of [4] Al, related to an increasing formation temperature (Henry & Dutrow, 1996), such tourmalines might show a positive correlation between F content and the formation Li-bearing tourmalines in Variscan pegmatites from Lower Austria Fig. 8.…”

mentioning

confidence: 99%

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Li-bearing tourmalines in Variscan granitic pegmatites from the Moldanubian nappes, Lower Austria

Ertl

Schuster

Hughes

et al. 2012

ejm

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Crystal structures, chemical (including light elements) and spectral data (optical and Mössbauer spectroscopies) were used to characterize coloured (brown, pink, green) tourmalines from three granitic pegmatites from the Moldanubian nappes (Königsalm, Maigen and Blocherleitengraben; Lower Austria). The tourmalines can be classified as fluor-schorl, schorl, foitite, magnesiofoitite, olenite and ''fluor-elbaite'' with varying Li contents, up to $1.2 wt% Li 2 O. Coexisting minerals are quartz, plagioclase (up to An 7), microcline, garnet (spessartine-almandine), muscovite, biotite (annite), very rare lepidolite, apatite, monazite-(Ce), xenotime-(Y), allanite-(Ce) and zircon. The chemical composition of the Fe 2þ-rich tourmaline samples (up to $1.0 wt% TiO 2) varies from fluorschorl, with a ¼ 15.987(2), c ¼ 7.163(2) Å to X (& 0.63 Na 0.37) Y (Fe 2þ 1.12 Al 1.09 Mg 0.56 Mn 2þ 0.08 Fe 3þ 0.07 Li 0.02 Ti 4þ 0.01 Zn 0.01 & 0.04) Z (Al 5.74 Mg 0.26) (BO 3) 3 [Si 5.96 Al 0.04 O 18 ] V (OH) 3 W [(OH) 0.95 F 0.05 ], strongly dichroic (pink and blue) foitite, with a ¼ 15.9537(2), c ¼ 7.1448(4) Å , to X (& 0.51 Na 0.49) Y (Fe 2þ 0.97 Al 0.93 Mg 0.75 Fe 3þ 0.23 Mn 2þ 0.04 Li 0.01 Ti 4þ 0.01 & 0.06) Z (Al 5.72 Mg 0.28) (BO 3) 3 [Si 5.95 Al 0.05 O 18 ] V (OH) 3 W [(OH) 0.91 O 0.06 F 0.03 ], magnesiofoitite, with a ¼ 15.9476(4), c ¼ 7.1578(4) Å. The chemical composition of the Al-and Lirich and Mn 2þ-bearing (up to $5.7 wt% MnO) samples varies from X (Na 0.84 Ca 0.02 & 0.14) Y (Al 1.35 Li 0.78 Mn 2þ 0.65 Ti 4þ 0.01 & 0.21) Z Al 6 (BO 3) 3 [Si 5.92 Al 0.04 B 0.04 O 18 ] V (OH) 3 W [F 0.81 (OH) 0.19 ], ''fluor-elbaite'' with a ¼ 15.8887(3), c ¼ 7.1202(3) Å , to X (Na 0.76 Ca 0.12 & 0.12) Y (Al 1.52 Li 0.69 Mn 2þ 0.43 Fe 2þ 0.09 & 0.27) Z Al 6 (BO 3) 3 [Si 5.71 B 0.29 O 18 ] V (OH) 3 W [F 0.69 (OH) 0.31 ], B-rich ''fluorelbaite'', with a ¼ 15.8430(3), c ¼ 7.1051(3) Å. A positive correlation between the ,T-O. and ,Z-O. bond lengths in tourmalines where the Z site is only occupied by Al (R 2 ¼ 0.617) is useful to correct the ,Z-O. bond length for the inductive effect of the varying ,T-O. bond length. This is important for producing accurate assignments for the different 6-coordinated sites in tourmaline. On the basis of Sm-Nd (garnet, monazite), U-Th-Pb, and U-Pb ages (monazite), the pegmatites crystallised during the Variscan tectonometamorphic event in the Visean (339 AE 4 Ma Maigen, 332 AE 3 Ma Königsalm). These ages are in the range of the earliest intrusions of the South Bohemian pluton (Rastenberg type durbachites). However, on the basis of the spatial relationship of the pegmatites and the Rastenberg type intrusions, a linkage of the intrusive body and the pegmatites is unlikely. Alternatively, the pegmatites may have evolved as granitic pegmatitic melts during decompression from the surrounding country rocks in the frame of exhumation of the Moldanubian nappes after the peak of the Variscan metamorphism.

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supporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Li-bearing tourmalines in Variscan granitic pegmatites from the Moldanubian nappes, Lower Austria

Ertl

Schuster

Hughes

et al. 2012

ejm

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“…We observed no significant difference in X-site vacancy in tourmalines T1 and T2. Within the wide constraints imposed by the crystal chemistry of tourmaline, petrological conditions are the main constraint on F-incorporation in tourmaline (Henry & Dutrow 2011), but the cause of the moderate correlation of Ca and F in our case remains unclear. Boron isotopic composition measured from three crystals in a cluster of prograde (T1) tourmalines and a single prograde (T2) tourmaline in sample TS-23 are similar: +10.8 ± 2.8‰ and +10.0‰, respectively (Table 8), giving +10.6 ± 2.3‰ as an average boron isotopic composition for prograde tourmaline.…”

Section: Prograde and Peak Metamorphismmentioning

confidence: 72%

A New Occurrence of the Borosilicate Serendibite in Tourmaline-Bearing Calc-Silicate Rocks, Portage-Du-Fort Marble, Grenville Province, Quebec: Evolution of Boron Isotope and Tourmaline Compositions in a Metamorphic Context

Belley¹,

Grice²,

Fayek³

et al. 2014

The Canadian Mineralogist

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Serendibite, Ca 1.93 Na 0.08 Mg 2.58 Al 5.03 B 1.53 Si 2.71 O 20 , was recently discovered in a lens of B-rich calc-silicate rock metamorphosed at 6-7 kbar, 650-700°C in the Central Metasedimentary Belt, Grenville Province. Based on paragenesis and tourmaline composition, which were used to monitor changes in fluid composition, the following stages of mineralization are recognized: (1) a prograde assemblage consisting of K-feldspar, tourmaline [T1 with X Ca = Ca/(Ca + Na) = 0.54, T2 with X Ca = 0.71], and calcite, inferred from relicts in scapolite; (2A) a peak metamorphic assemblage of aluminous diopside, serendibite, lesser phlogopite, and local scapolite (Me 62 ); (2B) continued formation of phlogopite around serendibite in calcite pockets although serendibite was stable; and (3) high-temperature breakdown of serendibite to uvite (T3; X Ca = 0.82) + spinel + calcite, and of aluminous diopside to pargasite. Three generations of idiomorphic magnesian tourmaline that crystallized in calcite pockets (T4 to T6) recorded fluid evolution as follows: (A) X Ca ≈ 0.5 and relatively moderate Ti concentrations (generation T4); (B) increase in Na relative to Ca, X Ca ≈ 0.3 (generation T5), with the rare occurrence of oligoclase (X Ca = 0.17) and relatively low Ti concentrations; and (C) X Ca ≈ 0.5, relatively high Ti concentrations (generation T6). The final stage is localized, low-temperature alteration to fine-grained phyllosilicates.The boron isotopic composition of peak metamorphic serendibite (δ 11 B = +4.3 ± 1.7‰) is lower than that of prograde tourmaline (δ 11 B = +10.6 ± 2.3‰) from which it formed. The fractionation difference between serendibite and metamorphic fluid (with B derived from prograde tourmaline), Δ 11 B Srd−Tur = δ 11 B Srd − δ 11 B Tur = −6.3‰, is similar to the ab initio calculated fractionation factor between serendibite and fluid (Δ 11 B Srd−fluid = −7.6 ± 1.4‰ at 727°C). Tetrahedral boron coordination in serendibite is largely responsible for this fractionation. High-temperature uvite replacement of serendibite is significantly higher in δ 11 B relative to serendibite (+10.6‰ versus +4.3‰), which is attributed to buffering of boron isotopes by serendibite in local equilibrium with uvite. Tourmalines formed in calcite pockets range from +8‰ to almost +12‰ on average, while the core of a T4 tourmaline has δ 11 B = +3.4‰. This low δ 11 B value is attributed to a temporary departure from equilibrium due to fluid influx. The boron isotope signature of prograde tourmaline suggests a marine evaporite source.a new occurrence of the borosilicate serendibite

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The Role of Halogens During Regional and Contact Metamorphism

Hammerli

Rubenach

2018

Springer Geochemistry

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The incorporation of fluorine in tourmaline: internal crystallographic controls or external environmental influences?

Cited by 57 publications

References 79 publications

Li-bearing tourmalines in Variscan granitic pegmatites from the Moldanubian nappes, Lower Austria

Li-bearing tourmalines in Variscan granitic pegmatites from the Moldanubian nappes, Lower Austria

A New Occurrence of the Borosilicate Serendibite in Tourmaline-Bearing Calc-Silicate Rocks, Portage-Du-Fort Marble, Grenville Province, Quebec: Evolution of Boron Isotope and Tourmaline Compositions in a Metamorphic Context

The Role of Halogens During Regional and Contact Metamorphism

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