Discovery of epidosites in the Mount Ślęża ophiolite (Fore-Sudetic Block, SW Poland)

Abstract

The first suite of epidosite from the Central Sudetic Ophiolites has been discovered in the sheeted dyke complex of the Mount Ślęża ophiolite (SW Poland). Epidosites from the Mount Ślęża ophiolite represent A-type epidosites which metasomatically replaced diabasic sheeted dykes of the Strzegomiany–Kunów Fe-Ti mineralisation zone. They form decimetre-scale elongated pistachio-green patches or veins within single dykes. Their composition (quartz + epidote + titanite) is analogue to Troodos ophiolite end-member epidosite of Cyprus. The pistacite content of epidote range from Ps₁₆ to Ps₃₁ and is similar to those from other ophiolitic epidosites. Titanite is low in Al₂O₃ (0.61 to 1.10 wt.%) and Fe₂O₃ (0.43 to 0.63 wt.%) and high in V2O5 (from 0.22 to 0.47 wt.%). The presence of epidosites in the Mount Ślęża ophiolite can be considered as an evidence of its supra-subduction zone (SSZ) affinity. Finally, a direct link between the epidosite formation and the release of base metals from its protolith (Cu, Zn and Co) indicates the possibility of the Cyprus-type volcanogenic massive sulphide deposit (VMS) formation in the Mount Ślęża ophiolite