Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

Pavel Povondra, Stanislav Vrána

Tourmaline and associated minerals in alkali-feldspar orthogneiss near Hluboká nad Vltavou, southern Bohemia

Journal of the Czech Geological Society, volume 41 (1996), issue 3-4, 191 - 200

Tourmaline in the Hluboká orthogneiss, a rock unit 7 by 2 km in outcrop size, is characterized by wet chemical analyses of four samples, microprobe analyses, unit-cell dimensions, density, and indices of refraction.The tourmaline composition range from sc₄₉-dr₃₆-ol₁₅ to sc₇₈-dr₁₁-ol₁₁; the content of the olenite end-member ranges up to 26 %. The associated major and accessory minerals are also characterized by microprobe analyses. The data obtained are compatible with primary magmatic crystallization of tourmaline in the pre-Variscan parent rock. A comparison of tourmaline composition in five related orthogneiss and granite-metagranite bodies in the Moldanubian Zone of south-central and eastern Bohemia shows significant similarities, except the Radonice orthogneiss, carrying a notably more magnesian tourmaline.