Abstract
Large phenocrysts of clinopyroxene, amphibole in the Godovar tuff show normal zoning with mg-values decreasing from the center towards the border zones. Clinopyroxenes exhibit a primitive Cr-diopsidic (Mg48Fe7Ca45) core which with a sudden change in the composition is surrounded by an augitic rim (Mg44Fe14Ca42). No such abrupt change can be observed in amphibole crystals which are typical pargasites and only the outermost zones may pass into the magnesio-hastingsite field. It is argued that the Cr-diopside may have separated from a basaltic liquid at depths greater than about 18 km, while the other pyroxene zones with the pargasite and plagioclase crystals accumulated in a storage chamber at a depth of about 12–15 km.
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