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

Origin of secondary amphibole in ultrabasic and basic rocks of the Ransko massif (E-Bohemia)


Pavel Schovánek, Ferry Fediuk, Josef Klomínský

Geoscience Research Reports 43, 2010 (GRR for 2009), pages 248–252

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The chemical composition and formation of secondary amphiboles in ultrabasic to basic rocks of the Ransko gabbro-peridotite massif have been studied. Primary calcium-rich plagioclases were altered into clay minerals, carbonates and/or thomsonite. The thin section study and the chemical analyses of these minerals revealed subsequent formation of amphiboles, frequently accompanied by pale-green ceylonite (spinel group). Serpentinization of olivine provided necessary Mg and Fe ions.