Stable isotopic constrains on the origin of epithermal Cu-Au and related porphyry copper mineralisations in the southern Panagyurishte district, Srednogorie zone, Bulgaria

摘要

The Panagyurishte district is characterised by a high abundance of copper and copper-gold deposits, related to an Upper Cretaceous magmatic activity in the central part of the Srednogorie metallogenic zone in Bulgaria. Quartz, hydroxyl-bearing alteration minerals, and some oxide minerals from the Elshitsa Au-Cu epithermal deposit and the Vlaykov Vruh porphyry-Cu deposit, from the southern part of the district, were analysed for their oxygen and hydrogen isotopic compositions to establish the source of paleohydro-thermal waters. The isotopic geothermometers record temperatures of ore deposition in the range 500-635°C during ore stages Ⅰ and Ⅱ at Vlaykov Vruh. The δ~(34) S values of sulphides and sulphates from both, the epi-thennal and the porphyry copper deposits indicate a magmatic origin of the sulphur and progressive oxidation of the mineralising fluids.