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  1. Article ; Online: The effect of fluorine on clinopyroxene/melt trace-element partitioning

    Beard, C. / van Hinsberg, V. / Stix, J. / Wilke, M.

    Contributions to Mineralogy and Petrology

    2020  

    Abstract: The impact of fluorine on phase relations and clinopyroxene–melt element partitioning has been explored experimentally to better understand the effect of this halogen on the residual enrichment of the REE and HFSE during crystallisation of alkaline and ... ...

    Abstract The impact of fluorine on phase relations and clinopyroxene–melt element partitioning has been explored experimentally to better understand the effect of this halogen on the residual enrichment of the REE and HFSE during crystallisation of alkaline and peralkaline magmas. Clinopyroxene was grown from three H2O-saturated synthetic glasses of tephriphonolite-to-phonolite composition in a rapid quench internally heated pressure vessel at 650–800 ∘C and 200 MPa, with Δlog fO2 fixed to ca. FMQ + 1. The fluorine content in the charges was varied and produced quenched melts from fluorine-free to 1.6 wt.% F. The experiments yield an assemblage of melt, fluid, sodic clinopyroxene, biotite, magnetite, ± K-feldspar, ± titanite, ± fluorite, and ± hiortdahlite (a Na-Ca-Ti-F sorosilicate). Addition of fluorine markedly increases the mode of biotite without significantly affecting the mode of clinopyroxene. Relative to fluorine-free compositions, experiments with 1.6 wt.% fluorine in the melt show a strong decrease in clinopyroxene–melt partition coefficients for the trivalent REE La–Dy and Y with a lesser decrease for the DHREE and DHFSE4+. The diminished uptake of these metals by clinopyroxene may reflect changes to their speciation in the melt phase, consistent with the formation of REE-F complexes and with modifications to the medium-range structural environment around HFSE4+ ions in the melt. An increase in the fluorine content of the melt will thus make the REE and HFSE4+ progressively less compatible and, therefore, available for residual enrichment.
    Subject code 550 ; 660
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Clinopyroxene/Melt Trace Element Partitioning in Sodic Alkaline Magmas

    Beard, C. / van Hinsberg, V. / Stix, J. / Wilke, M.

    Journal of Petrology

    2019  

    Abstract: Clinopyroxene is a key fractionating phase in alkaline magmatic systems, but its impact on metal enrichment processes, and the formation of REE + HFSE mineralisation in particular, is not well understood. To constrain the control of clinopyroxene on REE + ...

    Abstract Clinopyroxene is a key fractionating phase in alkaline magmatic systems, but its impact on metal enrichment processes, and the formation of REE + HFSE mineralisation in particular, is not well understood. To constrain the control of clinopyroxene on REE + HFSE behaviour in sodic (per)alkaline magmas, a series of internally heated pressure vessel experiments was performed to determine clinopyroxene–melt element partitioning systematics. Synthetic tephriphonolite to phonolite compositions were run H2O-saturated at 200 MPa, 650–825°C with oxygen fugacity buffered to log f O2 ≈ ΔFMQ + 1 or log f O2 ≈ ΔFMQ +5. Clinopyroxene–glass pairs from basanitic to phonolitic fall deposits from Tenerife, Canary Islands, were also measured to complement our experimentally-derived data set. The REE partition coefficients are 0·3–53, typically 2–6, with minima for high-aegirine clinopyroxene. Diopside-rich clinopyroxene (Aeg5–25) prefer the MREE and have high REE partition coefficients (DEu up to 53, DSm up to 47). As clinopyroxene becomes more Na- and less Ca-rich (Aeg25–50), REE incorporation becomes less favourable, and both the VIM1 and VIIIM2 sites expand (to 0·79 Å and 1·12 Å), increasing DLREE/DMREE. Above Aeg50 both M sites shrink slightly and HREE (VIri ≤ 0·9 Å ≈ Y) partition strongly onto the VIM1 site, consistent with a reduced charge penalty for REE3+ ↔ Fe3+ substitution. Our data, complemented with an extensive literature database, constrain an empirical model that predicts trace element partition coefficients between clinopyroxene and silicate melt using only mineral major element compositions, temperature and pressure as input. The model is calibrated for use over a wide compositional range and can be used to interrogate clinopyroxene from a variety of natural systems to determine the trace element concentrations in their source melts, or to forward model the trace element evolution of tholeiitic mafic to evolved peralkaline magmatic systems.
    Subject code 550
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: The imprint of hydrothermal fluids on trace element contents in white mica and tourmaline from the Panasqueira W-Sn-Cu deposit, Portugal

    Codeço, M. / Weis, P. / Trumbull, R. / Van Hinsberg, V. / Pinto, F. / Lecumberri-Sanchez, P. / Schleicher, A.

    Mineralium Deposita

    2021  

    Abstract: White mica and tourmaline are the dominant hydrothermal alteration minerals at the world-class Panasqueira W–Sn–Cu deposit in Portugal. Thus, understanding the controls on their chemical composition helps to constrain ore formation processes at this ... ...

    Abstract White mica and tourmaline are the dominant hydrothermal alteration minerals at the world-class Panasqueira W–Sn–Cu deposit in Portugal. Thus, understanding the controls on their chemical composition helps to constrain ore formation processes at this deposit and determine their usefulness as pathfinder minerals for mineralization in general. We combine whole-rock geochemistry of altered and unaltered metasedimentary host rocks with in situ LA-ICP-MS measurements of tourmaline and white mica from the alteration halo. Principal component analysis (PCA) is used to better identify geochemical patterns and trends of hydrothermal alteration in the datasets. The hydrothermally altered metasediments are enriched in As, Sn, Cs, Li, W, F, Cu, Rb, Zn, Tl, and Pb relative to unaltered samples. In situ mineral analyses show that most of these elements preferentially partition into white mica over tourmaline (Li, Rb, Cs, Tl, W, and Sn), whereas Zn is enriched in tourmaline. White mica has distinct compositions in different settings within the deposit (greisen, vein selvages, wall rock alteration zone, late fault zone), indicating a compositional evolution with time. In contrast, tourmaline from different settings overlaps in composition, which is ascribed to a stronger dependence on host rock composition and also to the effects of chemical zoning and microinclusions affecting the LA-ICP-MS analyses. Hence, in this deposit, white mica is the better recorder of the fluid composition. The calculated trace-element contents of the Panasqueira mineralizing fluid based on the mica data and estimates of mica-fluid partition coefficients are in good agreement with previous fluid-inclusion analyses. A compilation of mica and tourmaline trace-element compositions from Panasqueira and other W–Sn deposits shows that white mica has good potential as a pathfinder mineral, with characteristically high Li, Cs, Rb, Sn, and W contents. The trace-element contents of hydrothermal tourmaline are more variable. Nevertheless, the compiled data suggest that high Sn and Li contents are distinctive for tourmaline from W–Sn deposits.
    Subject code 550
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Book ; Article ; Online: Trace element contents in white mica and tourmaline from the Panasqueira W-Sn-Cu deposit (Portugal)

    Codeço, M. / Weis, P. / Trumbull, R. / van Hinsberg, V. / Pinto, F. / Lecumberri-Sanchez, P. / Schleicher, A.

    2020  

    Abstract: Analyzing the chemical composition of rocks and minerals is an important tool for exploring and understanding mineral resources. Typically, hydrothermal ore deposits are characterized by primary alteration halos. At the world-class Panasqueira W-Sn-Cu ... ...

    Abstract Analyzing the chemical composition of rocks and minerals is an important tool for exploring and understanding mineral resources. Typically, hydrothermal ore deposits are characterized by primary alteration halos. At the world-class Panasqueira W-Sn-Cu deposit, the hydrothermal alteration of the wall rocks produced concentric zones with progressively greater distance from the veins, consisting of a proximal tourmaline-quartz-muscovite zone and a distal muscovite-quartz zone. Tourmaline and mica are ubiquitous minerals at Panasqueira W-Sn-Cu and coexist in many other hydrothermal ore deposits worldwide. Both minerals are well-known to host variable amounts of trace elements and to have potential as pathfinder minerals as well as fluid monitors. We analyzed major, minor and trace element contents of altered and unaltered metasediments from the Panasqueira by XRF and ICP-MS and tourmaline and white mica major, minor and trace element compositions by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in previously well-characterized samples from different locations/setting in the mine (greisen, vein-selvages, wall-rock alteration zones, fault zone, and late vugs). Detailed information about the samples used, the location, and general geological background of the samples, and the analytical method is provided in the data description "2020-002_Codeco-et-al_data-description.pdf ". Detailed information about the the samples used, the location and general geological background of the samples and the analytical methods are provided in the data description file (2020-002_Codeco-et-al_data-description.pdf).
    Subject code 550
    Language English
    Publisher GFZ Data Services
    Publishing country de
    Document type Book ; Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Conference proceedings ; Online: Early ore-forming fluids at the world-class Panasqueira W-Sn-Cu deposit (Portugal). Insights from in situ micro-analytical techniques

    Codeço, M. / Weis, P. / Trumbull, R. / van Hinsberg, V. / Pinto, F. / Lecumberri-Sanchez, P.

    Geophysical Research Abstracts

    2018  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Conference proceedings ; Online: Aegirine-melt element partitioning in alkaline magmatic systems

    Beard, C. / van Hinsberg, V. / Stix, J. / Wilke, M.

    EMPG XV - Abstract Volume

    2016  

    Publishing country de
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    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Conference proceedings ; Online: Tourmaline-muscovite pairs as recorders of ore-forming processes at the Panasqueira W-Sn-Cu deposit (Portugal)

    Codeço, M. / Weis, P. / Trumbull, R. / van Hinsberg, V. / Glodny, J. / Wiedenbeck, M. / Romer, R. / Lecumberri-Sanchez, P.

    Abstracts with Programs

    2019  

    Abstract: Tourmaline and muscovite are common gangue minerals in magmatic-hydrothermal ore deposits. Tourmaline chemical and B-isotope compositions are widely used to constrain ore-forming conditions, sources and processes. Muscovite occurs in the same ... ...

    Abstract Tourmaline and muscovite are common gangue minerals in magmatic-hydrothermal ore deposits. Tourmaline chemical and B-isotope compositions are widely used to constrain ore-forming conditions, sources and processes. Muscovite occurs in the same environments as tourmaline and is a significant boron host, but its geochemical information has not been exploited to the same extent. We report on a study of B-isotope (SIMS) and chemical (microprobe, LA-ICP-MS) variations in coexisting tourmaline and muscovite from the Panasqueira W-Sn-Cu deposit in Portugal. This is the largest W-deposit in Europe and it consists of sub-horizontal, meter-thick W-Sn-Cu-bearing quartz veins hosted by clastic metasediments above the greisen cupola of a late-Variscan peraluminous granite. Tourmaline is the main hydrothermal mineral formed during alteration of the metasediments but it is absent from the greisen. The tourmaline has intermediate schorl-dravite compositions and is chemically zoned, with increases in Fe/Mg and F from core to rim, while Ca and Al contents decrease. The B-isotope composition (δ11B) of tourmaline ranges from -7 and -11‰ in 90% of the grains, consistent with a granitic source. There is no isotopic zoning but a slight variation with distance from the ore veins. Muscovite is abundant in the greisen and it forms cm-thick vein selvages, where it is locally intergrown with tourmaline. The median δ11B values of muscovite from the greisen and selvages are the same (-17 to -18‰), whereas late muscovite has lower values (to -23‰). The B-isotopic compositions of tourmaline-mica pairs are consistent with isotopic equilibrium as the system cooled from about 500° to 300°C. Muscovite has relatively high concentrations of lithophile elements (Li, Rb, Cs, Tl, Nb, W, Sn, and Ta) compared with tourmaline, which is richer in V, Sr, Ti, and Zn. This contrast relates partly to crystal-chemical differences but also to the fact that tourmaline formed mainly by mineral replacement in the host rocks whereas muscovite formed directly from the hydrothermal fluids and thus better reflects their composition.
    Subject code 550
    Language English
    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Conference proceedings ; Online: Using geochemistry and B-isotopes of hydrothermal tourmaline and mica to trace metals and fluid sources in the world-class class Panasqueira W-Sn-Cu deposit (Portugal)

    Codeço, M. / Weis, P. / Trumbull, R. / Robert, B. / van Hinsberg, V. / Pinto, F. / Lecumberri-Sanchez, P.

    Conference Proceedings

    2018  

    Abstract: The Panasqueira vein-type W-Sn-Cu deposit is hosted by Cambrian pelitic-psammitic metasediments and related to a greisenized S-type granite emplaced in the late stages of the Variscan orogeny. The origin of the mineralizing fluids, as well as the ... ...

    Abstract The Panasqueira vein-type W-Sn-Cu deposit is hosted by Cambrian pelitic-psammitic metasediments and related to a greisenized S-type granite emplaced in the late stages of the Variscan orogeny. The origin of the mineralizing fluids, as well as the hydrothermal processes and structural control on ore transport (e.g., role of greisen cupola vs. fault zones) and deposition, is still debated. We address the question of fluid source and evolution from the results of in situ microprobe (major and minor elements), LA-ICP-MS (minor and trace elements) and SIMS (B isotopes) measurements of coexisting tourmaline and white mica from different settings within the Panasqueira mine. White mica is one of the most abundant hydrothermal minerals in the deposit, including the ore veins, greisen and wall-rock alteration zones from the preore to the main ore stage. Tourmaline and quartz are the main phases forming the wall-rock alteration zones, but tourmaline is scarce in the veins, forming only locally at the vein margins and in late-stage fractures. White mica has muscovitic to phengitic and celadonitic compositions and relatively high concentrations of lithophile trace elements (Li, Rb, Cs, Tl, Nb, W, Sn, and Ta) that may logically derive from granite-related fluids. Contrarily, tourmaline has zoned dravitic-schorlitic compositions and is richest in V, Sr, Ti, and Zr that were likely supplied by the country rocks. Boron isotope compositions of tourmaline and white mica support a magmatic source for the early hydrothermal fluids. Furthermore, the fractionation of B isotopes between them provides estimates for the temperature of vein formation (ca. 460°C) and for a later fluid pulse recorded in crosscutting, mineralized fault zones (ca. 260°C). These results agree well with estimates from Ti-in-quartz thermometry from wall-rock alteration zones (500°C) and from the low end of homogenization temperatures for fluid inclusions in vein quartz (360°–230°C).
    Subject code 550
    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Tourmaline as a petrogenetic indicator in the Pfitsch Formation, Western Tauern Window, Eastern Alps

    Berryman, E. / Kutzschbach, M. / Trumbull, R. / Meixner, A. / van Hinsberg, V. / Kasemann, S. / Franz, G.

    Lithos

    2017  

    Abstract: Tourmaline is a common accessory mineral in the metasedimentary Pfitsch Formation located in the Pfitscher Joch (Passo de Vizze) area in the Tauern Window of the Eastern Alps. These post-Variscan metasedimentary units experienced peak metamorphic ... ...

    Abstract Tourmaline is a common accessory mineral in the metasedimentary Pfitsch Formation located in the Pfitscher Joch (Passo de Vizze) area in the Tauern Window of the Eastern Alps. These post-Variscan metasedimentary units experienced peak metamorphic conditions of ~ 550 °C, 1.0 GPa during the Alpine orogeny. Tourmaline is most abundant in a ~ 25 m thick unit of feldspathic gneiss (~ 20–200 μg/g B), where it occurs as idiomorphic crystals typically 10 mm in length. The abundance and size of the tourmaline crystals increase near coarse-grained quartzofeldspathic segregations (~ 1200 μg/g B), reflecting the mobilization and concentration of B by metamorphic fluids. Near segregations, individual tourmaline crystals have up to three growth zones, recording pro- (~ 350–500 °C, 0.7–1.0 GPa) and retrograde (~ 400 °C, 0.2 GPa) growth as determined by combining textural information and sector-zoning thermometry. Retrograde tourmaline occurs as individual crystals as well as overgrowths on prograde tourmaline crystals, especially on the surface of extensional fractures formed by E–W extension during regional decompression. Tourmaline in the Pfitsch Formation is dravitic with a variable Fe content that correlates with the Fe content of its respective host unit. Charge balance calculations suggest that a significant proportion of Fe in tourmaline is ferric, supporting the interpretation of a subaerial continental sedimentary protolith. Tourmaline near segregations has the highest inferred ferric iron content, which decreases across growth zones, potentially reflecting a reduction of the fluid during metamorphism. The Mg/(Mg + Fe) ratio increases with prograde tourmaline growth and decreases in retrograde overgrowths. In contrast, the Ca/(Ca + Na) ratio increases gradually from 0.05 to 0.20 with prograde growth and continues to increase up to 0.25 in the retrograde overgrowths, recording the maximum Ca/(Ca + Na) ratio of the fluid during Alpine metamorphism. The metasediments of the Pfitsch Formation have very low and variable whole-rock δ11B values (− 14.1 to − 33.6‰), with the highest values (− 17.7 to − 14.1‰) found in B-rich samples (165–1200 μg/g B) containing abundant tourmaline, and the lowest values (− 24.2 to − 33.6‰) in B-depleted samples (21–40 μg/g), which lack tourmaline. This observation supports preferential loss of 11B from the rocks during prograde metamorphism. Zoned tourmaline crystals in the Pfitsch formation show successively decreasing B isotope ratios from − 7.8 to − 11.2‰ in their cores and − 17.3 to − 20.3‰ in their rims. As supported by a Rayleigh fractionation model, the B-isotope values of the host rocks and the tourmaline crystals are most easily explained by the internal redistribution of B from a B-rich precursor mineral (e.g. mica) to the tourmaline during Alpine metamorphism.
    Subject code 550
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article: An experimental study of the solubility of baddeleyite (ZrO₂) in fluoride-bearing solutions at elevated temperature

    Migdisov, Art.A / Williams-Jones, A.E / van Hinsberg, V / Salvi, S

    Geochimica et cosmochimica acta. 2011 Dec. 1, v. 75, no. 23

    2011  

    Abstract: The solubility of baddeleyite (ZrO₂) and the speciation of zirconium have been investigated in HF-bearing aqueous solutions at temperatures up to 400°C and pressures up to 700bar. The data obtained suggest that in HF-bearing solutions zirconium is ... ...

    Abstract The solubility of baddeleyite (ZrO₂) and the speciation of zirconium have been investigated in HF-bearing aqueous solutions at temperatures up to 400°C and pressures up to 700bar. The data obtained suggest that in HF-bearing solutions zirconium is transported mainly in the form of the hydroxyfluoride species ZrF(OH)₃° and ZrF₂(OH)₂°. Formation constants determined for these species (Zr⁴⁺+nF⁻+mOH⁻=ZrFₙ(OH)ₘ°) range from 43.7 at 100°C to 46.41 at 400°C for ZrF(OH)₃°, and from 37.25 at 100°C to 43.88 at 400°C for ZrF₂(OH)₂°. Although the solubility of ZrO₂ is retrograde with respect to temperature, the measured concentrations of Zr are orders of magnitude higher than those predicted from theoretical extrapolations based on simple fluoride species (ZrF³⁺–ZrF₆ ²⁻). Model calculations performed for zircon show that zirconium can be transported by aqueous fluids in concentrations sufficient to account for the concentration of this metal at conditions commonly encountered in fluoride-rich natural hydrothermal systems.
    Keywords aqueous solutions ; solubility ; temperature ; zirconium
    Language English
    Dates of publication 2011-1201
    Size p. 7426-7434.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 300305-x
    ISSN 0016-7037
    ISSN 0016-7037
    DOI 10.1016/j.gca.2011.09.043
    Database NAL-Catalogue (AGRICOLA)

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