**3. Sampling and methods**

*Rare Earth Elements and Their Minerals*

microdiorites) [4, 5].

**2. Geological setting**

This manuscript concentrates on mineralogy and chemical composition of allanite which occurs as a relatively rare accessory mineral in some intermediate granitic rocks of the Moldanubian batholith of the Bohemian Massif. The Moldanubian batholith represents a large plutonic body in the Bohemian Massif composed of biotite granodiorites, granites, and two-mica granites together with some younger dykes (aplites, pegmatites, felsic granites, and microgranodiorites to

The Moldanubian batholith forms one of the plutonic complexes within the

Moldanubian batholith is built by multiple plutons, predominantly composed of granitic to granodioritic rocks with either S- or transitional I/S-type character [5–7]. All these granitic rocks can be classified into three main suites. These three suites are represented as (1) coarse-grained, porphyritic I- to I/S-type biotite granites to

[5] (**Figure 1**). In detail, the

Central European Variscan belt, covering 10,000 km2

*Geological map of the Moldanubian batholith (after [5], modified by the author).*

**22**

**Figure 1.**

Allanite was more commonly found in the Schlieren granite of the Weinsberg suite. As a relatively rare accessory mineral, allanite occurs also in diorites connected with granodiorites of the Weinsberg suite, in granodiorites of the Freistadt/ Mauthausen suite and in microgranodiorites occurring on the eastern margin of the Klenov pluton.

Allanite together with selected rock-forming minerals (plagioclase, biotite) was analyzed in polished thin sections. The back-scattered electron (BSE) images were acquired to study the internal structure of individual allanite grains. Element abundances of Al, Ca, Ce, Dy, Er, Eu, F, Fe, Gd, Ho, La, Lu, Mg, Mn, Na, Nd, P, Pb, Pr, Sc, Si, Sm, Sr, Tb, Th, Ti, Tm, U, Y, and Yb were determined using a CAMECA SX-100 electron microprobe operated in wavelength-dispersive mode. The concentrations of these elements were determined using an accelerating voltage and a beam current of 15 kV and 20 nA, respectively, with a beam diameter of 2–5 μm. The following standards, X-ray lines, and crystals (in parentheses) were used: AlKα—sanidine (TAP), CaKα—fluorapatite (PET), CeLα—CePO4 (PET), DyLα— DyPO4 (LiF), ErLα—ErPO4 (PET), EuLβ—EuPO4 (LIF), FeKα—almandine (LiF), GdLβ—GdPO4 (LiF), HoLβ—HoPO4 LiF), LaLα—LaPO4 (PET), LuMβ—LuAg (TAP), MgKα—spessartine (LIF), NdLβ—NdPO4 (LIF), PKα—fluorapatite (PET), PbMα—vanadinite (PET), PrLα—PrPO4 (LIF), SrLα—SrSO4 (TAP), ScKα—ScP5O14 (PET), SiKα—sanidine (TAP), SmLβ—SmPO4 (LIF), TbLα—TbPO4 (LIF), ThMβ— CaTh(PO4)2 (PET), TiKα—anatas (PET), TmLα—TmPO4 (LiF), UMβ—metallic U (PET), and YLα—YPO4 (PET). Intra-REE overlaps were partially resolved using Lα and Lβ lines. Empirically determined coincidences were applied after analysis: ThMα on the PbMα line and ThMγ on the UMβ line. The raw data were converted into concentrations using appropriate PAP-matrix corrections [20]. The detection limits were approximately 400 pm for Y, 180–1700 ppm for REE, and 800–1000 ppm for U and Th. The plot (REE + Y + Th + Mn + Sr) vs. Al proposed by Petrík et al. [21] was used for estimation of the Feox = Fe3+/(Fe3+ + Fe2+) ratio by electron microprobe analyzed allanite.
