scholarly journals REE and Y Mineralogy of the Krudum Granite Body (Saxothuringian Zone)

Minerals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 287 ◽  
Author(s):  
Miloš René
Keyword(s):  
Granite Body ◽  
Saxothuringian Zone

scholarly journals REE and Y Mineralogy of the Krudum Granite Body (Saxothuringian Zone)

2018 ◽  
Author(s):  
Miloš René
Keyword(s):  
Water Content ◽  
Analytical Data ◽  
Alkali Feldspar ◽  
Granitic Rocks ◽  
Granite Body ◽  
Saxothuringian Zone ◽  
Simultaneous Enrichment

The Krudum granite body comprises highly fractionated granitic rocks ranging from medium-F biotite granites to high-F, high-P2O5 Li-mica granites. This unique assemblage is an ideal site to continue recent efforts in petrology to characterize the role of zircon, monazite and xenotime as hosts to REEs. The granitic rocks of the Krudum body analysed in this study were found to contain variable concentrations of monazite and zircon, while xenotime was only found in the high-F, high-P2O5 Li-mica granites and in the alkali-feldspar syenites of the Vysoký Kámen stock. For analysed monazites of all magmatic suites cheralite substitution was significant. The highest concentration of cheralite was found in monazites from the high-F, Li-mica granites and from the alkali-feldspar syenites. The proportion of YPO4 in all analysed xenotimes ranges from 71 to 84 mol. %. Some xenotimes were found to be hydrated and the observed water content estimated from analytical data ranged from 5 to 11 wt. % H2O. Analysed xenotimes were commonly enriched in HREEs (9.3– 19.5 wt. % HREE2O3) and thorite-coffinite and cheralite exchange was observed. Analysed zircons from granite suites of the Krudum granite body contained moderate Hf concentrations (1.0–4.7 wt. % HfO2; 0.010–0.047 apfu Hf). The highest concentrations of HfO2 were found in zircons from the high-F, high P2O5 Li-mica granites (1.2–4.7 wt. % HfO2) and from the alkali-feldspar syenites (1.3–4.1 wt. % HfO2). Zircons from the high-F, high-P2O5 Li-mica granites were often hydrated and fluorised. The concentrations of F in zircon from partly greisenised high-F, high-P2O5 Li-mica granites reached up to 1.2 wt. % (0.26 apfu F). In zircons from the alkali-feldspar syenites enrichment in P, which is not associated with a simultaneous enrichment in Y + REE, was also observed. Analysed zircons from the high-F, high P2O5 Li-mica granites were enriched in Y (up to 5.5 wt. % Y2O3; 0.10 apfu Y) and Sc (up to 1.17 wt. % Sc2O3; 0.03 apfu Sc).

The nodular granite of Castanheira, north central Portugal: origin of the nodules and evidence for diapiric mobilization of granite

1993 ◽  
Vol 130 (2) ◽  
pp. 145-153 ◽  
Author(s):  
R. J. Reavy ◽  
D. H. W. Hutton ◽  
A. A. Finch
Keyword(s):  
Chemical Potential ◽  
Structural Data ◽  
Vapour Phase ◽  
Vapour Bubble ◽  
North Central ◽  
Host Granite ◽  
Low Viscosity ◽  
Granite Body ◽  
Central Portugal ◽  
Strong Depletion

AbstractThe Castanheira pluton in north-central Portugal is a small (1000 m × 600 m) granite body of Hercynian age which contains a remarkable abundance of granite-cored, biotite-rimmed nodules. The nodules are interpreted as representing original bubbles in the uppermost volatile-rich zone of a granitic pluton. Strong depletion in K and Rb in the host granite around the nodules suggests that the biotite is magmatic in origin. The nodules may have formed by reaction between chloroferrate(II) complexes in the vapour phase and silicate melt, possibly followed by condensation of the vapour phase to a small granitic core. Motion of the vapour bubble stabilized a gradient in chemical potential with respect to the host granite, giving rise to the nodules. Chemical, petrological and structural data suggest that the pluton was part of a larger granite body, which was forcefully emplaced during synchronous transcurrent shearing. The inferred presence of volatiles, in addition to the pervasive tourmalinization of the roof zone, suggest that the magma was halogen-rich; this may imply that the magma had low viscosity.

Ta and Sn concentration by muscovite fractionation and degassing in a lens-like granite body: The case study of the Penouta rare-metal albite granite (NW Spain)

2017 ◽  
Vol 82 ◽  
pp. 10-30 ◽  
Author(s):  
Francisco Javier López-Moro ◽  
Francisco García Polonio ◽  
Teresa Llorens González ◽  
José Luis Sanz Contreras ◽  
Agustina Fernández Fernández ◽  
...  
Keyword(s):  
Rare Metal ◽  
Nw Spain ◽  
Granite Body ◽  
Albite Granite
Sign in / Sign up

Export Citation Format

Share Document