Exploring the potential of Raman spectroscopy for crystallochemical analyses of complex hydrous silicates: II. Tourmalines

Watenphul, Anke; Burgdorf, Martina; Schlüter, Jochen; Horn, I.; Malcherek, Thomas; Mihailova, Boriana

doi:10.2138/am-2016-5530

Cited by 68 publications

(121 citation statements)

References 85 publications

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“…Sample thickness 88 μm. After heating at 900 °C, the sample became turbid and less transparent causing mixing of polarization directions 1997; Castañeda et al 2000;Bosi et al 2012b;Berryman et al 2015) or an alternative approach: the YZZ-triplets model (Watenphul et al 2016). The "traditional" and the YZZ-triplets models converge to the interpretation of the vibrational band of O1 but diverge for O3.…”

Section: (Oh) Band Assignmentmentioning

confidence: 99%

“…Such a condition of positional disorder at the Y sites, in fact, preserves the equivalence of three O3 sites as well as the presence of the threefold axis of symmetry. More details on the physical and crystallographic reasons of the YZZ-triplets model can be found in Watenphul et al (2016). Below we analyze how these two approaches are applied to the untreated dravite.…”

Section: (Oh) Band Assignmentmentioning

confidence: 99%

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Thermal stability of extended clusters in dravite: a combined EMP, SREF and FTIR study

2016

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Section: (Oh) Band Assignmentmentioning

confidence: 99%

Section: (Oh) Band Assignmentmentioning

confidence: 99%

Thermal stability of extended clusters in dravite: a combined EMP, SREF and FTIR study

2016

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“…The W sites are dominated by O. According to the ions at X, Y and W sites, the fuscous tourmaline is considered to be V-rich intermediate oxy-schorl-dravite [48][49][50]. Compositional variations of trace elements in sample YE-6 are shown in Figure 13c.…”

Section: Major and Trace Elements Of Color Zoned Sample And Tourmalinmentioning

confidence: 99%

Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Zheng

Guo

2019

Minerals

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Emerald from the deposit at Dayakou is classified as a vanadium-dominant emerald together with Lened, Muzo, Mohmand, and Eidsvoll emeralds. Although previous studies defined these V-dominant emeralds and traced the genesis of the Dayakou deposit, there has not been any systematic comparison or discrimination on V-dominant emeralds from these deposits. The origin of the parental fluid and the crystallization process of the Dayakou emerald remain controversial. In this study, both major and trace element signatures of 34 V-dominant samples from Dayakou are analyzed through electron microprobe analysis (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Dayakou emeralds are characterized by high ratios of V/Cr and the enrichment of Li, Cs, W, Sn, and As. These geochemical fingerprints indicate a parental fluid of an Early Cretaceous early-stage granitic fluid associated with Laojunshan granite. The considerable concentration variation of Rb, Cs, Ga and the presence of V-rich oxy-schorl-dravite inclusions in a color zoned sample suggest two generations of emerald precipitation. Thus, a more detailed idealized mineralization model for the Dayakou deposit is proposed. A series of plots, such as Rb vs. Cs, V vs. V/Cr, LILE vs. CTE, and Li vs. Sc, are constructed to discriminate the provenance of V-dominant emeralds. Minerals 2019, 9, 777 2 of 29 summarized emerald deposits worldwide and collected their chemical compositions. They defined Dayakou (China), Lened (Canada), Muzo (Colombia), Mohmand (Pakistan), and Eidsvoll (Norway) emeralds as typical V-dominant emeralds based on the greater content of V 2 O 3 than Cr 2 O 3 . Those V-dominant emeralds can be easily distinguished from Cr-dominant emeralds. However, there has not been a systematic comparison or discrimination of those V-dominant emeralds from various deposits. With regards to Dayakou emeralds, their chemical compositions have been recently reported [20], but not analyzed in detail. Trace elements of emerald are powerful indicators for determining the geographic provenance but the number of related studies is limited. For the first time, using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS) techniques, [21] and [16] determined the origin of emeralds from several deposits by trace elements data, such as Li, B, Rb, Cs, V, Cr, Sc, Ga, etc. So far, only [20] has reported trace elements of Dayakou emerald, but their work focused on the Al 3+ replacement degree and Cr/V ratio. The geochemical fingerprints of the Dayakou emerald are not yet determined.Besides, the trace element geochemistry of emeralds was used for building the genetic model. B, Ga, Ba, Sr, and alkali elements Li, Cs, and Rb are regarded as indicators of parental fluid and the fractionation and evolution for pegmatite [3,4,22,23]. Reference [24] reported the formation conditions of Dayakou emerald, but the crystallization process and the sources of emerald-forming fluids have yet to be determined.In thi...

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“…Raman spectroscopy is a widely applied method for the identification of minerals as well as recognition of their compositional relationships; it is also used frequently in studies of tourmalines [36][37][38][39][40][41][42][43][44]. Because of the particular location of OH groups, which are bound to the octahedral Y and Z cations in the tourmaline structure, the OH vibration bands code crystallochemical information on occupation of both octahedral sites.…”

Section: Raman Spectroscopymentioning

confidence: 99%

“…Because of the particular location of OH groups, which are bound to the octahedral Y and Z cations in the tourmaline structure, the OH vibration bands code crystallochemical information on occupation of both octahedral sites. Therefore, interpretation of the bands is useful in discussing distribution of octahedral cations between the Y and Z sites (e.g., [39,40,[42][43][44][45]). Figure 8 shows representative unoriented Raman spectra recorded on relicts of primary Li,Al-bearing schorl Tur IB and secondary fluor-elbaite Tur IIIA (with compositions close to analyses 225/2 and 225/4 presented in Table 3).…”

Section: Raman Spectroscopymentioning

confidence: 99%

Towards Zn-Dominant Tourmaline: A Case of Zn-Rich Fluor-Elbaite and Elbaite from the Julianna System at Piława Górna, Lower Silesia, SW Poland

et al. 2018

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Tourmalines are a group of minerals which may concentrate various accessory components, e.g., Cu, Ni, Zn, Bi, Ti, and Sn. The paper presents fluor-elbaite and elbaite from a dyke of the Julianna pegmatitic system at Piława Górna, at the NE margin of the Bohemian Massif, SW Poland, containing up to 6.32 and 7.37 wt % ZnO, respectively. Such high amounts of ZnO are almost two times higher than in the second most Zn-enriched tourmaline known to date. The compositions of the Zn-rich tourmalines from Piława Górna, studied by electron micropropy and Raman spectroscopy, correspond to the formulae: X (Na 0.733 Ca 0.013 0.254) Σ1 Y (Al 1.033 Li 0.792 Zn 0.755 Fe 2+ 0.326 Mn 0.094) Σ3 Z Al 6 (T Si 6 O 18)(BO 3) 3 V (OH) 3 W (F 0.654 OH 0.344), and X (Na 0.779 Ca 0.015 0.206) Σ1 Y (Al 1.061 Li 0.869 Zn 0.880 Fe 2+ 0.098 Mn 0.094) Σ3 Z Al 6 (T Si 6 O 18)(BO 3) 3 V (OH) 3 W (OH 0.837 F 0.163), respectively, with Zn as one of the main octahedral occupants. A comparison with other tourmalines and associated Zn-rich fluor-elbaite and elbaite from the pegmatite indicates that atypically high Zn-enrichment is not a result of Zn-Fe fractionation, but dissolution and reprecipitation induced by a late (Na,Li,B,F)-bearing fluid within the assemblage of gahnite spinel and primary schorl-type tourmaline. This strongly suggests Na-Li-B-F metasomatism of gahnite-bearing mineral assemblages as that is the only environment that can promote crystallization of a hypothetical Zn-dominant tourmaline. The compositions of the Zn-rich fluor-elbaite and elbaite suggest three possible end-members for such a hypothetical tourmaline species: NaZn 3 Al 6 (Si 6 O 18)(BO 3) 3 (OH) 3 (OH), (Zn 2 Al)Al 6 (Si 6 O 18)(BO 3) 3 (OH) 3 (OH) and Na(Zn 2 Al)Al 6 (Si 6 O 18)(BO 3) 3 (OH) 3 O by analogy with other tourmalines with divalent Y occupants, such as schorl/foitite/oxy-schorl and dravite/magnesio-foitite/oxy-dravite.

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Exploring the potential of Raman spectroscopy for crystallochemical analyses of complex hydrous silicates: II. Tourmalines

Cited by 68 publications

References 85 publications

Thermal stability of extended clusters in dravite: a combined EMP, SREF and FTIR study

Thermal stability of extended clusters in dravite: a combined EMP, SREF and FTIR study

Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Towards Zn-Dominant Tourmaline: A Case of Zn-Rich Fluor-Elbaite and Elbaite from the Julianna System at Piława Górna, Lower Silesia, SW Poland

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