Acta Musei Moraviae

Contribution to the knowledge of provenance of pebbles from the Upper Viséean conglomerates in the Drahany Hights: VI. – Skarnoid

The pebble of leucocratic biotite migmatite (plagioclase >> K-feldspar) with a small nodule of skarnoid rock (garnet+amphibole+magnetite+quartz) was found at locality Račice, Luleč conglomerates, Drahany Hights. Minerals from both rocks were studied in detail using electron microprobe and polarizing microscope. Thin transitional zone with An-enriched plagioclase (Ab_56–57 An₄₃ Or_0–1) is developer between skarnoid and migmatite. The mineral assemblages and chemical composition of minerals in skarnoid (almandine Alm_73–74Grs_14–16Prp₆Sps_2–3Adr_2–3, grunerite X_Fe = 0.63–0.64, ferri-ferrohornblende X_Fe = 0.74–75) and in host migmatite (plagioclase Ab_68–72 An_25–29 Or_1–4), are similar with those from the localities of magnetite-rich amphibolites from the Polička Unit or border facie of magnetite skarn in the Pernštejn area, Svratka Unit, respectively.