| Description |
This thesis provides a study of chemical composition of vesuvianite from skarns at selected localities of Bohemian Massif, with regard to their mineral assemblages. The samples of vesuvianite from Žulová, Vápenná, Bludov, Nedvědice and Moravské Bránice were studied using electron microanalysis (EMPA) in order to obtain composition of major and minor elements, and laser-ablation mass spectrometry with inductively coupled plasma (LA-ICP-MS) for determination of Li, Be, B, trace elements and REE. Vesuvianite samples from Žulová and Vápenná are compositionally very similar and characterized by a high Fe/Mg ratio, elevated contents of Na, Mn, and high contents of F, Be, Zn and Bi. Vesuvianite from Bludov is similar to the primary vesuvianite from Žulová; main differences include slightly lower Fe/Mg ratio, and lower contents of F, Li and Be. The vesuvianite from Žulová shows zoning reflected in from core-to-rim compositional changes. An increase of Fe, Be, B, Zn, and Sn contents from the crystal core to the crystal rim, accompanied by a decrease of Al, Mg, and F contents was observed. Vesuvianite sample from Žulová also contains a secondary vesuvianite which has very low contents of Li, Be, Mn, slightly lower Zn, and significantly lower Ti and Bi contents compared to the primary vesuvianite; on the other hand, it contains slightly higher amounts of B and multiple times higher contents of Mg, Sn, La and Ce. The two studied samples of vesuvianite from Nedvědice are rich in Mg, both vesuvianite samples have unusually high contents of As. The Nedvědice1 vesuvianite sample is unique by elevated contents of Na, Mn, Ti and F, very high contents of Li, Sn, Sb and Bi whereas the sample Nedvědice2 has a very high content of B, and an extremely low content of Bi which is otherwise very high in all other studied samples. Secondary vesuvianite in both Nedvědice samples is characterized by the Fe/Mg ratio lower than in primary vesuvianite. The secondary vesuvianite from Nedvědice1 sample has significantly lower contents of Al, F, Zn, and As, slightly lower Fe, Na, Mn, Bi, and higher contents of Mg, La and Ti. The secondary vesuvianite from the Nedvědice2 sample has higher B, Zn and significantly higher As contents compared to the primary vesuvianite. The vesuvianite from Moravské Bránice has higher contents of Li, Na, Mn and it is Ti-rich; it is also anomalously rich in rare earth elements (La and Ce).
|
