**2. Geological setting**

The titanite-spots granodiorites at the northern Mühlviertel (Austria) occur as small irregular intrusive bodies, concentrated in a local SSW-NNE zone, W of Schlägl. According the most recent geological map 1:200,000 [11], a biggest body that was sampled in the Schlägl quarry forms N-S intrusion, W of Schlägl. These magmatic bodies are enclosed in bigger intrusions of the fine- to medium-grained Mauthausen granites (**Figure 1**). The Mauthausen granites are part of the youngest Freistadt/Mauthausen I/S-type suite (320–310 Ma) of the Moldanubian batholith [12–16]. The titanite-spots granodiorites form small irregular bodies enclosed in these granites.

The titanite-spots granodiorites and tonalites from the Fürstenstein pluton occur in the SSW part of the Bavarian Forest (Germany) forming smaller bodies and blocks enclosed in the medium-grained, porphyritic Saldenburg biotite granites, which form the main part of the Fürstenstein pluton [3, 10, 17]. This pluton represents the largest intrusive body in the Bavarian Forest (**Figure 2**). These granites are equivalent to the Weinsberg medium- to coarse-grained, porphyritic biotite granites at the southern part of the Moldanubian batholith [3, 11]. The titanitespots granodiorites and tonalites occur predominantly in contact zones between the Saldenburg granites and the medium- to coarse-grained Tittling biotite granites and granodiorites. Their age as determined by Chen and Siebel [10] is 321 ± 4 Ma, by the U/Pb dating method in titanite.

#### **Figure 1.**

*Geological sketch map of the Šumava Moldanubian batholith branch after [1, 2], modified by the author.*

**43**

**4. Results**

**4.1 Petrography**

*Titanite from Titanite-Spots Granodiorites of the Moldanubian Batholith…*

Approximately 30 quantitative electron probe microanalyses of titanite were performed in the three representative samples of titanite-spots granodiorites from the western Mühlviertel area (Austria). Minerals were analyzed in polished thin sections, and back-scattered electron images (BSE) were acquired to study the interaction of examined titanite with surrounding minerals and the internal structure of individual mineral grains. Element abundances of Al, Ca, Ce, F, Fe, La, Mg, Na, Nb, Nd, Pr, Si, Ta, Th, Ti, Y, and Zr in selected accessory titanite were determined using a CAMECA SX 100 electron probe microanalyzer (EPMA) operated in wavelengthdispersive mode. The contents of the abovementioned elements were determined using an accelerating voltage and beam current of 15 keV 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); FKα, topaz (PC1); FeKα, almandine (LIF); LaLα, LaPO4 (PET); MgKα, Mg2SiO4 (TAP); NbLα, columbite (PET); NdLβ, NdPO4 (LIF); PrLβ, PrPO4 (LIF); SiKα, sanidine (TAP); TaLα, CrTa2O6 (LIF); TbLα, TbPO4 (LIF); ThMα, CaTh(PO4)2 (PET); TiKα, anatas (PET); YLα, YPO4 (PET); and ZrLα, zircon (TAP). Intra-REE overlaps were partially resolved using Lα and Lβ lines. The raw data were converted into concentrations using appropriate PAP matrix corrections [18]. The detection limits were approximately 400 ppm for Y and 180–1700 ppm for REE.

*Geological sketch map of the Fürstenstein pluton after [10], modified by the author.*

The titanite-spots granodiorites from the northern Mühlviertel are dark, fine-grained rocks with many light spots formed by plagioclase and bigger, usually

idiomorphic titanite crystals (**Figures 3** and **4**).

*DOI: http://dx.doi.org/10.5772/intechopen.88359*

**3. Analytical methods**

**Figure 2.**

*Titanite from Titanite-Spots Granodiorites of the Moldanubian Batholith… DOI: http://dx.doi.org/10.5772/intechopen.88359*

**Figure 2.** *Geological sketch map of the Fürstenstein pluton after [10], modified by the author.*
