Accessory minerals of the C�novec (Zinnwald) granite cupola, Czech Republic Part 1: Nb-, Ta- and Ti-bearing oxides

1994 ◽  
Vol 51 (2-4) ◽  
pp. 323-343 ◽  
Author(s):  
V. Johan ◽  
Z. Johan
Keyword(s):  
Czech Republic ◽  
Accessory Minerals

Ti–Zr–Nb-bearing accessory minerals in high-K trachyandesitic rocks from the Western Outer Carpathians, Moravia, Czech Republic

2018 ◽  
Vol 30 (1) ◽  
pp. 135-147 ◽  
Author(s):  
Ray MacDonald ◽  
Krzysztof Nejbert ◽  
Bogusław Bagiński ◽  
Edyta Jurewicz
Keyword(s):  
Czech Republic ◽  
Accessory Minerals ◽  
High K ◽  
Outer Carpathians

Stability relations of monazite-(Ce), gadolinite-(Ce), gadolinite-(Y), britholite-(Ce) and bastnäsite-(Ce) during late- to post-magmatic processes in nepheline syenite (Čistá pluton, Czech Republic)

2021 ◽  
Author(s):  
Maciej Jaranowski ◽  
Bartosz Budzyń ◽  
Gabriela A. Kozub-Budzyń ◽  
Jiří Sláma ◽  
Josef Klomínský
Keyword(s):  
Czech Republic ◽  
Nepheline Syenite ◽  
Oscillatory Zoning ◽  
Accessory Minerals ◽  
Fine Grained ◽  
Science Centre ◽  
Magmatic Processes ◽  
Alteration Processes ◽  
Quantitative Analyses ◽  
Research Grant

<p>Stability relations of the REE-bearing accessory phases and alteration processes in the cancrinite-bearing nepheline syenite from the Čistá pluton (the center of the upper-crustal Tepla–Barrandian unit, Bohemian Massif, Czech Republic) were studied. Observations of rock microtextures, quantitative analyses of minerals and compositional X-ray mapping were performed using electron probe microanalysis (EPMA). The primary REE-bearing accessory minerals assemblage includes monazite-(Ce) associated with gadolinite-group minerals (i.e. gadolinite-(Ce) and gadolinite-(Y)), which were partially replaced by britholite-(Ce), bastnäsite-(Ce), aggregates of fine-grained REE-bearing phases (possibly fluorapatite and/or britholite-(Ce)) and, rarely, cerianite. K-feldspar and albite form intergrowths or symplectites with REE-phases in the investigated reaction microtextures. Furthermore, the zircon crystals demonstrate oscillatory zoning and/or extensive patchy zoning due to alteration processes. The alteration of accessory minerals are interpreted as driven by K- and Na-bearing alkali fluids with high CO<sub>2</sub> activity during late- to post-magmatic processes.</p><p>Acknowledgements: This work was supported by the National Science Centre research grant no. 2017/27/B/ST10/00813.</p>

scholarly journals Komplexní magmaticko-hydrotermální vývoj columbitu, mikrolitu a fersmitu z beryl-columbitového pegmatitu D6e u Maršíkova, Česká republika

2020 ◽  
Vol 28 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Štěpán Chládek ◽  
Pavel Uher
Keyword(s):  
Czech Republic ◽  
Granitic Pegmatite ◽  
Accessory Minerals ◽  
Partial Dissolution ◽  
Pegmatite Body ◽  
Magmatic Fluids ◽  
Compositional Variations ◽  
Homogeneous Pattern ◽  
Oscillatory Zonation

The recently rediscovered small D6e granitic pegmatite body, enclosed in amphibole gneiss of the Sobotín amfibolite massif (Jeseníky Mountains, Czech Republic), is characterized by numerous accessory minerals, including common columbite group minerals (CGM) and minor microlite and fersmite related to blocky K-feldspar unit. The CGM show complex internal zoning. Primary magmatic columbite-(Mn) occurs as corroded domains of prevailing homogeneous pattern, followed by less evolved oscillatory zonation. Primary CGM were overprinted by extensive recrystallization controlled by late-magmatic to post-magmatic fluids and leading to a formation of complex patchy and convolute oscillatory domains of secondary (hydrothermal) CGM. Primary columbite-(Mn) shows significantly limited Ta/(Ta+Nb) and Mn/(Mn+Fe) ratios, whereas secondary columbite-(Fe) to -(Mn) show slightly wider Fe-Mn and Nb-Ta compositional variations. Complex textures and the element fluctuations indicate a partial dissolution-reprecipitation of primary CGM caused by late- to post-magmatic fluids. Moreover, late calciomicrolite I, II and fersmite precipitated on the cracks of columbite crystals. Rare U-rich calciomicrolite I was extensively replaced by fersmite and oscillatorily zoned U-poor calciomicrolite II, slightly enriched in F. Their formation sequestrated part of hydrotermally released Na, Ca, U and represents the final subsolidus fluid-driven stage of the pegmatite evolution. Textural and compositional variations of Nb-Ta mineralization point to a complex magmatic to hydrothermal evolution of the D6e beryl-columbite pegmatite similar to other pegmatites in this region.

Social variation in size at birth and preterm delivery in the Czech Republic and Sweden, 1989-91

1998 ◽  
Vol 12 (1) ◽  
pp. 7-24 ◽  
Author(s):  
Koupilova ◽  
Vagero ◽  
Leon ◽  
Pikhart ◽  
Prikazsky ◽  
...  
Keyword(s):  
Czech Republic ◽  
Preterm Delivery ◽  
The Czech Republic ◽  
Social Variation ◽  
Size At Birth
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