Komatiite-meimechitic character of ultrabasic rocks of the Železný Brod Crystalline Area

Geoscience Research Reports 39, 2006 (GRR for 2005), pages 109–110

Full text (PDF, 0.07 MB)

Abstract

Serpentinised ultrabasic rocks occurring as dykes in the epimetamorphic crystalline complex of the southern foreground of the Jizerské hory Mts., have been hitherto described under various names: picrite, serpentinite, wehrlite, serpentinised peridotite etc. Using the IUGS classification, they comply with all parameters (Si02 30 to 52%, MgO > 18 % and Na20 + K20 < 3%) for "high-Mg" volcanics and their low Ti02 content around 1 % ranges them on the komatiite/meimechite boundary. Their geochronological setting within the broad Early Paleozoic time span remains still poorly understood.