NOVÁK, Milan, Petr ČERNÝ and Pavel UHER. Extreme variation and apparent reversal of Nb-Ta fractionation in columbite-group minerals from the Scheibengraben beryl-columbite pegmatite, Maršíkov, Czech Republic. European Journal of Mineralogy. Stuttgart, 2003, vol. 15, No 5, p. 565-574. ISSN 0935-1221.
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Basic information
Original name Extreme variation and apparent reversal of Nb-Ta fractionation in columbite-group minerals from the Scheibengraben beryl-columbite pegmatite, Maršíkov, Czech Republic
Authors NOVÁK, Milan (203 Czech Republic, guarantor), Petr ČERNÝ (124 Canada) and Pavel UHER (703 Slovakia).
Edition European Journal of Mineralogy, Stuttgart, 2003, 0935-1221.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 10500 1.5. Earth and related environmental sciences
Country of publisher Germany
Confidentiality degree is not subject to a state or trade secret
Impact factor Impact factor: 1.185
RIV identification code RIV/00216224:14310/03:00009085
Organization unit Faculty of Science
Keywords in English Extreme variation and apparent reversal of Nb-Ta fractionation in columbite-group minerals from the Scheibengraben beryl-columbite pegmatite; Maršíkov; Czech Republic
Tags Czech Republic, Maršíkov
Changed by Changed by: prof. RNDr. Milan Novák, CSc., učo 36021. Changed: 9/12/2004 09:38.
Abstract
Compositional variation in columbite-group minerals was studied from the beryl-columbite pegmatite at Scheibengraben, Maršíkov, Northern Moravia, Czech Republic. The pegmatite consists of five textural-paragenetic units, from the least to the most evolved: volumetrically dominant coarse-grained unit, subordinate graphic and blocky units and a minor cleavelandite unit. Saccharoidal albite unit is rather randomly distributed within the dike. It replaces and/or crosscuts all other units except the cleavelandite unit. Columbite-group minerals are the dominant Nb,Ta-oxide phases in all units. They are associated with other Nb,Ta-oxide minerals: minerals of the pyrochlore subgroup and fersmite in the coarse-grained unit, and minerals of the microlite subgroup, ferrotapiolite and rynersonite in the cleavelandite unit. The extreme Nb-Ta [Ta/(Ta+Nb) = 0.06 to 0.97 (microlite 0.99)] and appreciable Fe-Mn [Mn/(Mn+Fe) = (ferrotapiolite 0.22) 0.35 to 0.90] fractionations in columbite-group minerals differ from those observed in beryl pegmatites examined to date, but they are comparable with those in some highly fractionated, complex, Li-rich pegmatites. High activity of F (facilitated by low contents of B, P and Li in the pegmatite melt) very likely maximized such an extensive Nb-Ta fractionation, over and above differential solubilities of columbite and tantalite in pegmatite melt. The apparent reversal of Nb-Ta and Fe-Mn fractionation found in columbite from the saccharoidal albite unit seems to be an artefact from early units (particularly the coarse-grained one), which were extensively replaced by saccharoidal albite.
Links
IAA3046002, research and development projectName: Akcesorické minerály Ti, Nb, Ta a W jako indikátory geochemického vývoje magmatických a hydrotermálních systémů v Českém masívu
Investor: Academy of Sciences of the Czech Republic, Accessory minerals of Ti,Nb,Ta and W as indicators of geochemical evolutions in magmatic rocks and related and hydroth. systems of the Bohem. Ma.
MSM 143100004, plan (intention)Name: Geologické procesy a jejich environmentální vyústění - styk variscid a alpid
Investor: Ministry of Education, Youth and Sports of the CR, Geological Processes and their Environmental Impact - Contact of the Variscides and Alpides
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