Issue 60

M. Vyhlídal et alii, Frattura ed Integrità Strutturale, 60 (2022) 13-29; DOI: 10.3221/IGF-ESIS.60.02

minerals such as graphite, quartz, muscovite, and pyrite rarely occur, some of them even only as accessories. The rock exhibits massive to plane parallel structure and granoblastic texture. Microscopic views of the rocks used for inclusion preparation are shown in Fig. 2.

Figure 2: Micrographs of the studied rocks (polished thin sections, transmitted light, crossed polarizers). A – amphibolite, B – basalt, C – granite, D – marble. Rock-forming mineral abbreviations (in alphabetical order): Amp – amphibole, Bt – biotite, Cal – calcite, Kfs – K-feldspar, Mag – magnetite, Ol – olivine, Pl – plagioclase, Px – pyroxene, Py – pyrite, Qtz – quartz, Zrn – zircon. The chemical composition of the rocks used for inclusion preparation was determined semiquantitatively using a XEPOS X-ray fluorescence (XRF) energy dispersive spectrometer (Spectro Analytical Instruments GmbH, Germany). The milled rock sample was mixed with wax and a tablet was moulded and then analysed in a protective atmosphere (He). The results of determining the chemical compositions of the rocks are shown in Tab. 1.



Inclusion

SiO 2

TiO 2

Al 2 O 3

Fe 2 O 3 * MnO MgO

CaO

Na 2 O

K 2 O

P 2 O 5

LOI

Amphibolite

44.80

0.88

15.25

12.08

0.22

9.56

12.47

1.57

1.05

0.05

1.57

99.50

Basalt

42.21

2.66

13.36

13.72

0.22

8.26

12.90

3.80

0.76

0.97

0.56

99.42

Granite

71.60

0.29

13.70

2.68

0.04

0.41

1.95

3.45

5.02

0.11

0.43

99.68

Marble 99.85 Explanations: * = iron in the form of Fe 2 O 3 , LOI = loss-on-ignition; the samples were burned in a muffle furnace for 3 hours at 1100ºC Table 1: Chemical composition of rock inclusions determined using XRF spectrometry [%]. 2.31 0.12 1.12 0.72 0.01 0.70 53.10 0.19 0.21 0.06 41.31

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