Hydrothermal alteration in volcanic rocks, eastern part of the Lukavice Group, Železné Hory Mountains, Czech Republic
✍ Scribed by Z. Pertold; D. H. Watkinson; L. Novotný
- Book ID
- 104662578
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 572 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0026-4598
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✦ Synopsis
Many rocks mapped as felsic metavolcanics in the eastern part of the Lukavice Group are shown to be altered mafic metavolcanics, similar to those in the Noranda and Flin Flon-Snow Lake mining districts, Canada. The relatively fresh rocks of the Lukavice Group are rhyolite, dacite-andesite, and andesite-basalt of calcalkaline character. Assuming no substantial volume change during alteration, Ti, P, La, Ce, Yb, Lu, Th (partly), Sc and V contents remained unchanged. Altered rocks are enriched in (Fe + Mg), K and Si and depleted in Na, Ca and Zr. Some elements show both increased and decreased contents in altered rocks (Mg, Ba, Sm, Eu, Tb and Hf). Although hydrothermal alteration in the Lukavice Group is of large extent, it is of the proximal Kuroko style and not of regional 'Amulet Rhyolite' style. Implications for a large hydrothermal system within a volcanic pile are discussed in relation to the Ordovician Lukavice Group and its mineral deposits and to some other parts of the Bohemian Massif with volcanosedimentary sequences of the same age.