Vertical zonality of fractionated granite plutons reflected in zircon chemistry: the Cínovec A-type versus the Beauvoir S-type suite

Breiter, Karel; Škoda, Radek

doi:10.2478/v10096-012-0030-6

Cited by 31 publications

(26 citation statements)

References 47 publications

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“…Additional mineralogical and geochemical data were presented in Rub et al (1983Rub et al ( , 1997Rub et al ( , 1998, Cocherie et al (1991), and Dolejš and Štemprok (2001). The compositions of rock-forming minerals including some accessory minerals were determined by electron microprobe analyses by Johan and Johan (2005), Johan et al (2012) and Breiter and Škoda (2012). The results of the new sampling and new interpretation of chemical analyses were presented at workshop held in Prague in 2015 (Breiter et al 2015a, b;Rambousek and Knésl 2015).…”

Section: Petrography and Modal Composition Of The Granite Cupolamentioning

confidence: 99%

Drill hole CS-1 penetrating the Cínovec/Zinnwald granite cupola (Czech Republic): an A-type granite with important hydrothermal mineralization

Stemprok¹

2016

J. Geosci.

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The Sn-W deposit at Cínovec and Zinnwald (Eastern Krušné hory/Erzgebirge) is associated with a granite cupola of Late Variscan age intruded into the Teplice rhyolite. The 1596 m deep CS-1 drilling was completed in [1961][1962][1963] at Cínovec in the center of the granite cupola. This paper reviews earlier and new petrological and geochemical data revealed by the CS-1 drill core. The drill-log showed that the upper granite zone of the cupola consists of lepidolite-albite granite grading continuously into zinnwaldite granite in fine-grained and medium-grained variants. Below 730 m depth, medium-grained, porphyritic lithian annite granite enclosing small bodies of porphyritic lithian annite microgranite was observed. Chemical analyses of the drill core are discussed in terms of increasing depth, significant textural variations and trace-element concentrations for As, Ba, Be, Bi, Mo, Nb, Rb, Sn, Th, U, Y, W, and Zr. The zinnwaldite/lithian annite transition in the granite profile is well demonstrated by the abrupt changes in Li, Fe and Ti concentrations with depth. High concentrations of Sn, W, and Bi are mainly confined to the greisen zones, associated with both sub-horizontal and steep fissure systems. As a consequence of subsolidus albitization, the pink coloration of lithian annite granite was changed to white-grey in the upper cupola zone above c. 730 m depth. The textural changes are interpreted as modifications of earlier microgranites by the later emplacement of medium-grained granites along sharp contacts. The major effect of subsolidus hydrothermal alteration is manifested by pervasive development of lepidolite and zinnwaldite at the expense of earlier lithian annite and by an intense albitization (Ab ~98 mol. %) reaching a depth of c. 730 m below the surface. The hydrothermal overprinting in the CS-1 drill core is interpreted to be caused by fluids derived from a deep lower crustal source, probably near the boundary with the mantle, as witnessed by the coexistence of lamprophyres and albite-rich granites in several ore districts of the Krušné hory/Erzgebirge with Li, Sn, and W mineralization. lower crust to form granitic magmatism and providing the addition of rare metals derived from the mantle (Štemprok and Seifert 2011).According to the fractional crystallization hypothesis, compatible elements are progressively removed from a melt. Consequently smaller volumes of differentiated melt become enriched in incompatible components and volatiles, including water, which eventually exsolve. The dyke equivalents of albite-rich granitic rocks known locally as "ongonite" in Mongolia (Kovalenko et al. 1970), appeared at that time to support this hypothesis.Fractional crystallization hypothesis differs from the metasomatic model of the origin of rare-metal granites developed by Jacobson et al. (1958) in anorogenic granites of Northern Nigeria and by Beus et al. (1962) in post-collisional settings on the territory of the former USSR. This mechanism accounts for the metasomatic overprinting of the endocontacts of mi...

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Section: Petrography and Modal Composition Of The Granite Cupolamentioning

confidence: 99%

Drill hole CS-1 penetrating the Cínovec/Zinnwald granite cupola (Czech Republic): an A-type granite with important hydrothermal mineralization

Stemprok¹

2016

J. Geosci.

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“…Th content is quite variable in both greisen types but the mean Th content of the greisens from Zinnwald is with 61 ppm lower than in the surrounding rhyolite but higher than in albite granite. The overall highest Th and U contents, however, were found in greisen samples, which may be due to sporadically occurring thorite and thorianite in the albite granite (Breiter and Škoda, 2012) which potentially concentrates during greisenization as Th is insoluble. The greisens from the Nebelstein area, in contrast, have a far lower mean Th content of 10.7 ppm which is only little lower than in the surrounding two-mica -4 granite.…”

Section: Discussionmentioning

confidence: 89%

Multi-parameter petrophysical characterization of Variscan greisen rocks from the Southern Bohemian Batholith (Austria) and the Eastern Erzgebirge Volcano-Plutonic Complex (Germany)

Müller-Huber¹,

Börner²

2017

AJES

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Understanding the variation and correlation between physical properties of ore bodies of interest is vital for every exploration project. Therefore comprehensive petrophysical laboratory measurements on representative sample material from two dispersemineralized greisen bodies of the Southern Bohemian Batholith (Austria) and the Eastern Erzgebirge Vulcano-Plutonic Complex (Germany), respectively, are presented in this study. As many greisen bodies host mineral deposits of economic interest, the aim of the study was to identify petrophysical properties which are suitable for distinguishing greisen bodies from the surrounding rocks. The gathered physical information (density, porosity, velocity, magnetic susceptibility, gamma spectroscopy, electrical resistivity, spectral induced polarization (SIP)) indicates that a differentiation of mineralized greisen zones of interest from the surrounding rocks is only possible based on a combined investigation of several parameters. Elevated grain and bulk densities (mean: 3 2.75 g/cm and 2.67 g/cm , respectively) are indicative of the Erzgebirge low-porosity (mostly < 3%) mineralized greisen rocks in comparison to the lower densities of the surrounding Teplice rhyolite and albite granite. Bulk density, however, is critically influenced by porosity and is therefore not suitable to distinguish the Austrian greisen rocks from the surrounding two-mica granites, 3 despite the greisens' comparably high grain density (mean: 2.74 g/cm ). Their higher porosity (mean: 5.7%) also results in lower elastic wave velocities (mostly < 2900 m/s) and lower electrical resistivities (mostly < 2100 Ohmm) than the surrounding rocks. The electrical resistivities and elastic wave velocities of the German greisen samples are, in contrast, rather variable with no distinct level above or below the neighboring rocks. Magnetic susceptibility also delivers a good contrast between the greisens and their surrounding rocks as it is highly responsive to elevated mica contents or the presence of oxidic ore minerals. If quartz content predominates or oxidic ores are absent, however, there is no contrast in the magnetic susceptibility of the greisens and the surrounding rocks. With regard to natural gamma radiation, the greisens are characterized by generally low absolute readings as well as low U counts, while K and Th counts seem to be dependent on mica type. Results from SIP measurements suggest that especially phase information can be used to adequately differentiate greisen zones associated with Li-mineralization from country rocks in the Erzgebirge. In Austrian greisen rocks, however, the characteristics of the SIP spectra are less distinct. A crossplot of the real vs. the imaginary part of complex conductivity, however, is suitable for identification of rocks with high mica content. Based on these results a combined investigation of density, magnetic susceptibility, and spectral gamma seems to be most promising for identification of greisen bodies. und dem Auftreten von oxidischen Erzmineralen ko...

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“…Moderate to strong deviation of altered zircon from stoichiometry was also found in other occurrences of high-F, Li-mica granites in the Krušné Hory/Erzgebirge area (e.g., Cínovec, Podlesí, Altenberg, Seifen [33,36,47,48] as well as in altered zircon worldwide [49][50][51][52][53][54].…”

Section: Substitution In Zirconmentioning

confidence: 99%

“…Enrichment of non-formula elements such as P, Al, Ca, Y and REE in P-rich zircon was found also in some other high-P peraluminous granites worldwide [7,[34][35][36]. The entry of Y + HREE and P into the zircon structure is usually explained via xenotime substitution, whereas zircon and xenotime are isostructural [37][38][39].…”

Section: Substitution In Zirconmentioning

confidence: 99%

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

René

2018

Minerals

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Abstract:The Krudum granite body comprises highly fractionated granitic rocks ranging from medium-F biotite granites to high-F, high-P 2 O 5 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 rare earth elements (REEs). The granitic rocks of the Krudum body analyzed in this study were found to contain variable concentrations of monazite and zircon, while xenotime was only found in the high-F, high-P 2 O 5 Li-mica granites and in the alkali-feldspar syenites of the Vysoký Kámen stock. Intermediate trends between cheralite and huttonite substitutions are characteristic for analyzed monazite grains from all magmatic suites. The highest concentration of cheralite was found in monazite from the alkali-feldspar syenites (up to 69.3 mol %). The proportion of YPO 4 in analyzed xenotime grains ranges from 71 to 84 mol %. Xenotime grains are commonly enriched in heavy rare earth elements (HREEs; 9.3-19.5 wt % HREE 2 O 3 ) and thorite-coffinite and cheralite exchange was observed. Some xenotime analyses return low totals, suggesting their hydration during post-magmatic alterations. Analyzed zircon from granite suites of the Krudum granite body contains moderate Hf concentrations (1.0-4.7 wt % HfO 2 ; 0.010-0.047 apfu Hf). The highest concentrations of HfO 2 were found in zircon from the high-F, high-P 2 O 5 Li-mica granites (1.2-4.7 wt % HfO 2 ). Analyzed zircon grains from the high-F, high-P 2 O 5 Li-mica granites and alkali-feldspar syenites are enriched in P (up to 8.29 wt % P 2 O 5 ; 0.24 apfu P), Al (0.02-2.0 wt % Al 2 O 3 ; 0.00-0.08 apfu Al), Ca (up to 3.9 wt % CaO; 0.14 apfu Ca), Y (up to 5.5 wt % Y 2 O 3 ; 0.10 apfu Y), and Sc (up to 1.17 wt % Sc 2 O 3 ; 0.03 apfu Sc). Zircon grains from the high-F, high-P 2 O 5 Li-mica granites were sometimes hydrated and fluorized. The concentrations of F in zircon from partly greisenised high-F, high-P 2 O 5 Li-mica granites reached up to 1.2 wt % (0.26 apfu F).

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Vertical zonality of fractionated granite plutons reflected in zircon chemistry: the Cínovec A-type versus the Beauvoir S-type suite

Cited by 31 publications

References 47 publications

Drill hole CS-1 penetrating the Cínovec/Zinnwald granite cupola (Czech Republic): an A-type granite with important hydrothermal mineralization

Drill hole CS-1 penetrating the Cínovec/Zinnwald granite cupola (Czech Republic): an A-type granite with important hydrothermal mineralization

Multi-parameter petrophysical characterization of Variscan greisen rocks from the Southern Bohemian Batholith (Austria) and the Eastern Erzgebirge Volcano-Plutonic Complex (Germany)

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

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