Tourmaline, an indicator of external Mg-contamination of granitic pegmatites from host serpentinite; examples from the Moldanubian Zone, Czech Republic

Novák, Milan; Prokop, J.; Losos, Zdeněk; Macek, Ivo

doi:10.1007/s00710-017-0512-4

Cited by 15 publications

(10 citation statements)

References 53 publications

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“…Moreover, the amount of Ca in studied tourmalines increases from the primary to the secondary stage (Figs 5a, 6a). Hence, the source of Ca was melt contamination at pre-emplacement stage and during, or slightly after, emplacement to the site of crystallization (post-emplacement stage; Novák et al , 2017. This is consistent with the results of Teertstra et al (1999) and Novák et al (1999).…”

Section: Contamination and Behavior Of Mg And Casupporting

confidence: 85%

“…Magnesium is usually exhausted during crystallization of early minerals (biotite, tourmaline) in outer pegmatite units. In moderately fractionated pegmatite units (e.g., albite units), Mg is depleted (e.g., Jolliff et al 1986;Selway et al 1999;Novák et al 2017). Pyrope component in garnet is generally confined to high pressures.…”

Section: Contamination and Behavior Of Mg And Camentioning

confidence: 99%

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Secondary blue tourmaline after garnet from elbaite-subtype pegmatites; implications for source and behavior of Ca and Mg in fluids

Buřival¹,

Novák²

2018

J. Geosci.

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Secondary blue tourmaline (schorl to Fe-rich fluor-elbaite to very rare Fe-rich fluor-liddicoatite) with quartz partially replace spessartine-almandine garnet and albite in elbaite-subtype pegmatites cutting pyroxene gneisses and calcite or dolomite marbles (at Tamponilapa and Tsarafara-Nord, Sahatany Valley, Madagascar) and paragneisses (at Ctidružice, Moldanubian Zone, Czech Republic). Only garnet from the albite adjacent to an unit with Li-bearing minerals (Li-micas, Li-tourmalines) underwent this alteration, whereas associated primary tourmaline (schorl to Mg-bearing schorl) remained unaltered. O Elevated contents of Al, Fe, Na and Mn in secondary tourmaline were likely sourced from the replaced garnet and albite, whereas the residual fluids supplied B, F, Li, and H 2 O. Garnet and associated primary tourmaline are rather Mg-rich but the secondary tourmaline is typically Mg-free. The contents of Ca are high in both tourmaline generations, but the secondary one is occasionally even more enriched compared to the associated primary tourmaline. Such a behavior of Mg and Ca suggests that no Mg was externally supplied during primary crystallization of primary tourmaline from the moment when pegmatite melt was sealed off the host rock. Negligible to none concentrations of Mg in secondary tourmaline show that the pegmatite system was closed to the host rocks during the hydrothermal alteration producing the secondary tourmaline generation. Evident absence of external Mg-contamination from host Ca, Mg-rich rock rules out also any contamination by Ca. High contents of Ca in primary tourmaline and garnet are related to originally Ca--enriched pegmatite melt contaminated before emplacement.

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Section: Contamination and Behavior Of Mg And Casupporting

confidence: 85%

Section: Contamination and Behavior Of Mg And Camentioning

confidence: 99%

Secondary blue tourmaline after garnet from elbaite-subtype pegmatites; implications for source and behavior of Ca and Mg in fluids

Buřival¹,

Novák²

2018

J. Geosci.

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“…The fourth and fifth mechanisms are described in tourmalines from pegmatites contaminated by host serpentinites in the Moldubian Zone, Czech Republic (Novák et al, 2017) (Čerńy et al, 1985, London 2008, Roda-Robles et al, 2015 and Ministerskaya is the most evolved pegmatite among those studied here.…”

Section: Discussionmentioning

confidence: 84%

“…The fourth and fifth mechanisms are described in tourmalines from pegmatites contaminated by host serpentinites in the Moldubian Zone, Czech Republic (Novák et al , 2017). Pegmatites were divided into A, B and C types in their zoning and mineralogy: from unzoned and mineralogical simple type A to zoned and mineralogical complex type C including lithium minerals.…”

Section: Discussionmentioning

confidence: 99%

Iron-bearing to iron-rich tourmalines from granitic pegmatites of the Murzinka pluton, Central Urals, Russia

Гвозденко

Бакшеев

Ханин

et al. 2022

MinMag

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“…Whether there is an external or internal source of Ca in subsolidus processes in granitic pegmatites is a matter of discussion, and an external source has been suggested (e.g. Martin and De Vito, 2014; Novák et al , 2017). Further, the temperature of these external fluids might be slightly higher relative to stage (2).…”

Section: Fluid-mediated Alteration Of Microlitesmentioning

confidence: 99%

Microlite-group minerals: tracers of complex post-magmatic evolution in beryl–columbite granitic pegmatites, Maršíkov District, Bohemian Massif, Czech Republic

Chládek

Uher

Novák

et al. 2021

MinMag

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Microlite-group minerals occur as common replacement products after primary and secondary columbite-group minerals (CGM) in albitised blocky K-feldspar and in coarse-grained, muscovite-rich units of the Schinderhübel I, Scheibengraben and Bienergraben beryl–columbite pegmatites in the Maršíkov District (Silesian Unit, Bohemian Massif, Czech Republic). Textural and compositional variations of microlite-group minerals were examined using electron probe micro-analyses and microRaman spectroscopy (μRS). A complex post-magmatic evolution of the pegmatites and the following microlite populations (Mic) and related processes were found: (1) precipitation of U, Na-rich and F-poor Mic I on cracks in CGM; (2) alteration of Mic I to U-rich together with Na- and F-poor Mic II; and (3) partial replacement of Mic I and II by Mic III with a distinct Na, U and Ti loss and Ca and F gain. Stage (2) includes an extensive leaching of Na, without U loss. The final stage (3) produced euhedral-to-subhedral oscillatory zoned Ca and F enriched Mic III with distinctly different composition to the previous F-poor and A-site vacant Mic II. Aggregates of fersmite are associated commonly with Mic III. Distal Mic IIId occurs locally on cracks in K-feldspar or quartz, with compositions analogous to Mic III. Compositional variations and textural features of microlite-group minerals during dissolution–reprecipitation processes serve as sensitive tracers of post-magmatic evolution in granitic pegmatites recording complex interactions between magmatic pegmatite units and externally derived, hydrothermal metamorphic fluids.

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Tourmaline, an indicator of external Mg-contamination of granitic pegmatites from host serpentinite; examples from the Moldanubian Zone, Czech Republic

Cited by 15 publications

References 53 publications

Secondary blue tourmaline after garnet from elbaite-subtype pegmatites; implications for source and behavior of Ca and Mg in fluids

Secondary blue tourmaline after garnet from elbaite-subtype pegmatites; implications for source and behavior of Ca and Mg in fluids

Iron-bearing to iron-rich tourmalines from granitic pegmatites of the Murzinka pluton, Central Urals, Russia

Microlite-group minerals: tracers of complex post-magmatic evolution in beryl–columbite granitic pegmatites, Maršíkov District, Bohemian Massif, Czech Republic

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