Bulletin Mineralogie Petrologie

Research of plagioclase by the descriptive method of frequency histograms was applied to file of microprobe analyzes of plagioclase in greywackes of the Teplá-Barrandian units. The set of analyzes of the author's article (Lang 2000) provides sufficient amount of analyzes to using descriptive frequency histograms of the An values and median Or. Or content in relation to An component varies according to the genesis of plagioclase (rock), especially, plagioclases of orthogneiss, migmatite and paragneiss. The results shaw that the statistical analysis of the main components of feldspar (An, Ab, Or) will have application in all, feldspar containing rocks. Many things indicate that it will be possible to differentiate the development of feldspar in different geological regions.

Fediuk F. (1971) Optické určování bazicity a stupně strukturní uspořádanosti plagioklasů. Universita Karlova, 128, Praha.

Fediuk F. (1972) Determination of the anorthite content and the ordering degree of plagioclases by zone method. Acta Univ. Carol., Geologica 4, 277-286.

Hunahashi M., Woo Kim Ch., Ohta Y., Tsuchiya T. (1968) Co-existence of plagioclases of different compositions in some plutonic and metamorphic rocks. Lithos 1, 356-373.

Cháb J., Pelc Z. (1968) Lithology of Upper Proterozoic in the NW limb of Barrandian. Krystalinikum 6, 141-167.

Cháb J., Breiter K., Fatka O., Hladil J., Kalvoda J., Šimůnek Z., Štorch P., Vašček Z., Zajíc J., Zapletal J. (2008) Stručná geologie základu Českého masivu a jeho karbonského a permského pokryvu. Vyd. Česká geol. služba 286, Praha.

Lang M. (1975) Bazicita a uspořádanost plagioklasů peceradského gabra. In: Palivcová M. (ed.): Peceradské gabro. Studie ČSAV 12, 107-123, Academia, Praha.

Lang M. (1978) Plagioklasy dioritů a gaber středočeského plutonu. MS, kandidátská disertace, Geologický ústav ČSAV, 1-77.

Lang M. (2000) Composition of Proterozoic Greywackes in the Barrandian. Věst. Čes. geol. Úst., 75, 205-216.