Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

Discovery of lamproite at Řípov near Třebíč, Moldanubicum

 

Lukáš Krmíček, Stanislav Houzar

Geoscience Research Reports 45, 2012 (GRR for 2011), pages 181–184
Map sheets: Třebíč (23-42)

Full text (PDF, 1.55 MB)

 

Abstract

A new occurrence of a 2 m wide peralkaline dyke was discovered along the eastern margin of the Moldanubian Zone at Řípov near Třebíč (western Moravia, Czech Republic). The dyke was classified as a lamproite. The investigated rock is characterised by abundant phenocrysts of phlogopite together with minor microcline and pseudomorphosed olivine or pyroxene. The dyke matrix consists of "alkaline" amphiboles, alkali feldspars (microcline and albite) minor clinoproxene and apatite. The peralkaline dyke has high Si02 (61.1 wt. %), MgO (7.45 wt. %) and Cr (493 ppm) contents, along with very high contents of K20 (7.92 wt. %) and Ba (3615 ppm), and only a low CaO (3.69 wt. %). The Řípov lamproite belongs to the Variscan orogenic lamprophyre-cocite-lamproite association recently recognised in the eastern partofthe Bohemian Massif.