A multiple regression method for estimating Li in tourmaline from electron microprobe analyses

Pesquera, Alfonso; Crespo, Pedro Pablo Gil; Torres-Ruiz, Francisco; Torres-Ruíz, J.; Roda-Robles, Encarnación

doi:10.1180/minmag.2016.080.046a

Cited by 31 publications

(27 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For analyses showing OH + F > 4 apfu due to excesses of microprobe determined SiO 2 (quartz nanoinclusions), the amount of the component was reduced to a value for which the stoichiometric OH + F = 4 apfu was achieved, i.e., the highest content accepted for the tourmaline structure. The estimation of the Li 2 O amounts from EMPA on the basis of a multiple regression equation given by Pesquera et al [33] is not applicable in our case, because the calculated Li 2 O amount seems to be ZnO dependent for high ZnO contents (Figure 3). Comparing the contents of Li 2 O obtained from our calculation procedure and the amounts from the regression equation by Pesquera et al [33], all data points corresponding to Zn-rich tourmaline deviate distinctly from the 1:1 trend and, in our opinion it is due to high contents of ZnO, a component which was not included as an important independent variable in the multiple regression by Pesquera et al [33].…”

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 73%

“…Comparing the contents of Li 2 O obtained from our calculation procedure and the amounts from the regression equation by Pesquera et al [33], all data points corresponding to Zn-rich tourmaline deviate distinctly from the 1:1 trend and, in our opinion it is due to high contents of ZnO, a component which was not included as an important independent variable in the multiple regression by Pesquera et al [33]. [33]. Symbols: dark squares-analyses with ZnO < 1.20 wt %, grey diamonds-analyses with ZnO > 3.50 wt %.…”

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 92%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 73%

Section: Electron Microprobe Analysis (Empa)mentioning

confidence: 92%

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

View full text Add to dashboard Cite

show abstract

“…The raw data were reduced with the PAP routine of Pouchou and Pichoir (1991). The estimation of the Li 2 O amounts from EPMA results on the basis of a multipleregression equation of Pesquera et al (2016) did not give positive result because the calculated Li 2 O amount (in wt%) is distinctly ZnO dependent for higher ZnO contents (Pieczka et al 2018).…”

Section: Electron Probe Microanalysis (Epma)mentioning

confidence: 99%

“…Pesquera et al (2016) derived a statistical equation allowing the calculation of Li 2 O content in wt% from the amounts of main oxide components of Li-bearing tourmalines such as SiO 2 , Al O 3 , total Fe as FeO and MnO. However, as shown by Pieczka et al (2018), this method does not work well, if a tourmaline is enriched by an atypical component, e.g.…”

mentioning

confidence: 99%

Crystal structure and Raman spectroscopic studies of OH stretching vibrations in Zn-rich fluor-elbaite

Pieczka

Ertl

Gołębiowska

et al. 2020

American Mineralogist

View full text Add to dashboard Cite

show abstract

“…3a). Chemical analyses demonstrate that the host is a X ☐-W O-W F-rich elbaite with the average composition: (Na 0.54 ☐ 0.41 Ca 0.05 ) (Al 1.79 Li 1.08 Mn 0.12 Fe 0.01 ) Al 6.0 (Si 5.91 Al 0.09 ) (BO 3 ) 3 O 18 (OH 3 ) (F 0.37 OH 0.37 O 0.27 ), based on normalization to 15 Y+Z+T with Li estimated by the Pesquera et al (2016) approach, calculated B (to 3.0 apfu) and calculated OH (based on charge balance). Individual fibers display three distinct tourmaline generations showing effects of partial dissolution and reprecipitation, with each generation having distinct compositions (Fig.…”

Section: Tourmaline Recording the Transition From Magmatic-to--hydrotmentioning

confidence: 99%

Tourmaline compositions and textures: reflections of the fluid phase

Dutrow¹,

Henry²

2018

Jour. Geosci.

View full text Add to dashboard Cite

Tourmaline uniquely records evidence of its geologic history in its composition and, if properly decoded, provides insight into the geologic environment of formation. Recent studies suggest that tourmaline not only retains chemical information on the host-rock environment, but also provides signatures on the fluid phase with which it interacted. Such signatures are embedded in its major-and minor-element compositions as well as in its isotopes. Some of these elemental signatures are qualitative, while others provide quantitative evaluation of the evolving fluid-phase compositions. Chemical fingerprints of interacting fluids are found as compositional variations in each of the tourmaline structural sites. Boron, a fluid-mobile element, can be used to monitor local release of boron from the breakdown of pre-existing B-bearing minerals or it can provide evidence for infiltration of external fluids. The exchange of Fe 3+ for Al in deprotonated tourmalines along the oxy-dravite to povondraite join (O-P trend) is generally consistent with tourmaline formation coexisting with fluids in an oxidizing, saline environment. Fluorine can serve as a marker for F-bearing aqueous fluids, but the crystallochemical constraints associated with vacancies on the X site and the resulting increase in local charge on the Y site must be considered. In some cases, quantitative information derived from Na, Ca, K, and vacancies allow calculation of the compositions of select components in the co-existing fluids. While isotopes provide valuable insights into fluid-related processes, their signatures are beyond the scope considered here. Insights into geological processes in fluid-rich environments can be inferred by the presence of tourmaline as well as by tourmaline compositions. For example, tourmaline forming along shear zones suggests that enhanced permeability accompanied infiltration of Na and B-bearing fluids. Oscillatory-zoned tourmaline from geothermal systems captures chemical, thermal, and mechanical feedback from non-linear fluid behavior at critical conditions in the H 2 O-system. In other cases, textural, morphological and chemical changes in tourmaline mark the transition from magmatic-to-hydrothermal conditions during the evolution of igneous systems. Consequently, signatures in tourmaline can be indicators of the fluid-phase composition and, in some cases, provide quantitative estimates of ion concentrations in the fluid in addition to its host rock environment. Capturing these chemical signals of fluids preserved in tourmaline extends its petrogenetic utility.

show abstract

A multiple regression method for estimating Li in tourmaline from electron microprobe analyses

Cited by 31 publications

References 27 publications

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

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

Crystal structure and Raman spectroscopic studies of OH stretching vibrations in Zn-rich fluor-elbaite

Tourmaline compositions and textures: reflections of the fluid phase

Contact Info

Product

Resources

About