Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn–W–Li deposit, Central Europe

Breiter, Karel; Ďurišová, Jana; Hrstka, Tomáš; Korbelová, Zuzana; Vaňková, Michaela; Galiová, Michaela Vašinová; Kanický, Viktor; Rambousek, Petr; Knésl, Ilja; Dobeš, Petr; Dosbaba, Marek

doi:10.1016/j.lithos.2017.08.015

Cited by 73 publications

(48 citation statements)

References 44 publications

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“…Hosking and Polkinghorne (1954) pointed out that wolframites in Cornish pegmatites are relatively Mn-rich while wolframites from quartz veins have high Fe contents. Greisens generally have wolframites with intermediate Fe/Mn (e.g., Breiter et al, 2017;Hosking and Polkinghorne, 1954). Several studies have suggested that Mn-rich wolframites precipitate at higher temperatures than Fe-rich wolframites (e.g., Oelsner 1944, Leutwein 1952, Taylor and Hosking 1970.…”

Section: Introductionmentioning

confidence: 99%

The H/F ratio as an indicator of contrasted wolframite deposition mechanisms

Michaud

Pichavant

2019

Ore Geology Reviews

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Understanding wolframite deposition mechanisms is a key to develop reliable exploration guides for W. In quartz veins from the Variscan belt of Europe and elsewhere, wolframites have a wide range of compositions, from hübnerite-(MnWO 4 ) to ferberite-rich (FeWO 4 ). Deposition style, source of Mn and Fe, distance from the heat/fluid source and temperature have been proposed to govern the wolframite H/F (hübnerite/ferberite ratio) defined as 100 at. Mn / (Fe + Mn). The Argemela mineralized district, located near the world-class Panasqueira W mine in Portugal, exposes a quartz-wolframite vein system in close spatial and genetic association with a rare-metal granite.Wolframite is absent as a magmatic phase, but W-rich whole-rock chemical data suggest that the granite magma is the source of W. Wolframite occurs as large homogeneous hübnerites (H/F = 64-75%) coexisting with montebrasite, K-feldspar and cassiterite in the latest generation of intragranitic veins corresponding to magmatic fluids exsolved from the granite. Locally, early hübnerites evolve to late more Fe-rich compositions (H/F = 45-55%). In a country rock vein, an early generation of Fe-rich hübnerites (H/F = 50-63%) is followed by late ferberites (H/F = 6-23%). Most Argemela wolframites have H/F ratios lower than at Panasqueira and other Variscan quartz-vein deposits which dominantly host ferberites. In greisens or pegmatitic veins, wolframites generally have intermediate H/F ratios. In those deposits, fluid-rock interactions, either involving country rocks (quartz-veins) or granite (greisens) control W deposition. In contrast, at Argemela, wolframite from intragranitic veins was deposited from a magmatic fluid. Differentiation of highly evolved peraluminous crustal magmas led to high Mn/Fe in the fluid which promoted the deposition of hübnerite. Therefore, the H/F ratio can be used to distinguish between contrasted deposition environments in perigranitic W ore-forming systems. Hübnerite is a simple mineralogical indicator for a strong magmatic control on W deposition.

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Section: Introductionmentioning

confidence: 99%

The H/F ratio as an indicator of contrasted wolframite deposition mechanisms

Michaud

Pichavant

2019

Ore Geology Reviews

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“…Beauvoir stock in France [30,31], the Yichun complex in China [32] and the Limu complex in China [33]. In comparison with these localities, the high-F, high-P2O5 Li-mica granites from the Geyersberg, Krásno-Horní Slavkov ore district [5] and this study, Podlesí [34] and the high-F, low P2O5 Li-mica granites of the Cínovec granite cupola [2,35] of the eastern Krušné Hory/Erzgebirge batholith show a lower degree of granite fractionation and, consequently, a higher Nb/Ta ratio. The Nb enrichment of these granites probably reflects a slightly different nature of the protolith [36].…”

Section: Discussionmentioning

confidence: 68%

Nb–Ta–Ti Oxides in Topaz Granites of the Geyersberg Granite Stock (Erzgebirge Mts., Germany)

René

2019

Minerals

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Oxide minerals (Nb–Ta-rich rutile, columbite-group minerals and W-bearing ixiolite) represent the most common host for Nb, Ta and Ti in high-F, high-P2O5 Li-mica granites and related rocks from the Geyersberg granite stock in the Krušné Hory/Erzgebirge Mts. batholith. This body forms a pipe like granite stock composed of fine- to middle-grained, porphyritic to equigranular high-F, high-P2O5 Li-mica granites, which contain up to 6 vol. % of topaz. Intrusive breccia’s on the NW margin of the granite stock are composed of mica schists and muscovite gneiss fragments enclosed in fine-grained aplitic and also topaz- and Li-mica-bearing granite. Columbite group minerals occur usually as euhedral to subhedral grains that display irregular or patched zoning. These minerals are represented by columbite-(Fe) with Mn/(Mn + Fe) ratio ranging from 0.07 to 0.15. The rare Fe-rich W-bearing ixiolite occurs as small needle-like crystals. The ixiolite is Fe-rich with relatively low Mn/(Mn + Fe) and Ta/(Ta + Nb) values (0.10–0.15 and 0.06–0.20, respectively). Owing to the high W content (19.8–34.9 wt. % WO3, 0.11–0.20 apfu), the sum of Nb + Ta in the ixiolite does not exceed 0.43 apfu. The Ti content is 1.7–5.7 wt. % TiO2 and Sn content is relatively low (0.3–4.1 wt. % SnO2).

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“…The many measurement types and acquisition modes of the TIMA system were tested at the Institute of Geology of the Czech Academy of Sciences in numerous scientific projects in areas spanning from ore geology (Haluzová et al 2015), through paleontology and paleoecology (Slavík et al 2016), petrology (Svojtka et al 2016;Žák et al 2016;Ackerman et al 2017;Breiter et al 2017Breiter et al , 2018, archaeology (Neumannová et al 2016), ecology/contaminated soil analysis (Harvey et al 2017) to dust analysis (Hrstka et al 2017b). The majority of the applications have been linked to the fast collection of statistically robust data on mineral composition and textural characteristics, together with the ability to quickly search for specific minerals or phases within geological samples.…”

Section: Case Studiesmentioning

confidence: 99%

Automated mineralogy and petrology - applications of TESCAN Integrated Mineral Analyzer (TIMA)

Hrstka¹,

Gottlieb²,

Skála³

et al. 2018

Jour. Geosci.

153

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The collection of representative modal mineralogy data as well as textural and chemical information on statistically significant samples is becoming essential in many areas of Earth and material sciences. Automated Scanning Electron Microscopy (ASEM) systems provide an ideal solution for such tasks. This paper presents the methods and techniques used in the recently developed TESCAN Integrated Mineral Analyzer (TIMA-X) with Version 1.5 TIMA software. The benefits from the use of a fully integrated quantitative energy-dispersive X-ray spectrometry (EDS) and an advanced statistical approach to ASEM systems are demonstrated. Typically, the system can handle more than 500,000 X-ray events per second. Using a common spectral total of 1000 events this represents the acquisition of 500 spectra per second. A number of measurement modes is available to make the most effective use of these spectra depending on the application. For a back-scattered electrons (BSE) map combined with EDS data with spatial resolution of 10 µm, this represents the high-resolution measurement of c. 1 cm 2 of a thin section or a polished rock surface in 30 minutes. A patented X-ray spectrum clustering algorithm that lowers the chemical detection limit is described and an example of its use is shown. The modal and textural (liberation, association, size etc.) data produced are statistically robust and provide information across a broad range of Earth and material sciences. A comparison with some other available instruments is also provided together with a number of case studies.

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Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn–W–Li deposit, Central Europe

Cited by 73 publications

References 44 publications

The H/F ratio as an indicator of contrasted wolframite deposition mechanisms

The H/F ratio as an indicator of contrasted wolframite deposition mechanisms

Nb–Ta–Ti Oxides in Topaz Granites of the Geyersberg Granite Stock (Erzgebirge Mts., Germany)

Automated mineralogy and petrology - applications of TESCAN Integrated Mineral Analyzer (TIMA)

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