RE-EXAMINATION OF THE HISTORICAL ORE SAMPLES FROM THE Au-Ag-Pb-Zn EPITHERMAL MINERALISATION AROUND PARADFUERDOE, RECSK ORE COMPLEX (NE-HUNGARY)

摘要

The Paradfuerdoe area is a part of the Paleogene Recsk Ore Complex. The studied mineralisation is located above a mineralized diorite intrusion and is hosted by altered dacite and dacitic tuff units. The ore mineralisation is controlled by siliceous veins and hydrothermal breccia dykes. The ore formation generally started with the precipitation of pyrite, but some pyrite crystals contain bornite, calaverite, hessite, tetradymite and aikinite inclusions. The presence of aikinite was not known previously. Two different pyrite textures are observable in the samples: euhedral pyrite crystals with mineral inclusions, and a collomorph pyrite-marcasite intergrowth. Based on the pyrite-marcasite intergrowth it can be assumed that the system oscillated around the pyrite/marcasite stability boundary. A reaction rim can be observed around the galena grains, which also reflects major changes in the hydrothermal solution. Raman spectroscopy ascertained the presence of phosgenite, covellite, cerussite and anglesite within this rim. The last formed minerals are the tetrahedrite and tennantite. The chalcopyrite usually represents a boundary between the sphalerite and fahlore crystals and forms small inclusions in sphalerite. It presumably formed as a reaction product, when at the final stage the FeS content of the sphalerite reacted with a later Cu-rich fluid.