FLUID INCLUSION CHARACTERISTICS AND PALEOTHERMAL STRUCTURE OF THE ADULARIA-SERICITE TYPE EPITHERMAL DEPOSIT AT TELKIBANYA-TOKAJ MTS, NORTHEAST HUNGARY

Fluid inclusion data for quartz, adularia, calcite and sphalerite rela ted to mineralization hosted by Neogene volcanic rocks at Telkibanya i n northeast Hungary indicate that the temperature varied between 270 d egrees C and 130 degrees C during hydrothermal activity intensive boil ing of fluids took place at about 230 degrees C, and the apparent sali nity of the hydrothermal solution was less than or equal to 5 NaCl equ iv. wt %. The CO2-content of initial solutions (pre-boiling fluids on 240-250 degrees C) was about 0.8 mol/kg on the basis of the model calc ulations. as a consequence of boiling a vapor-rich nearly isothermal s ystem developed in the vuggy-brecciated zones of host rocks around ore veins. Euhedral quartz that precipitated in these zones is morphologi cally different from the vein-filling quartz aggregates. Homogenizatio n temperatures indicate that the quartz veins formed under non-isother mal conditions. The paleotemperature distribution was reconstructed on the basis of the spatial distribution of average homogenization tempe ratures of quartz vein samples, and taking into account the level diff erences of sampling. A comparison of the paleotemperature map with the volcanotectonic map indicates that some of the areas of high paleotem perature are located along the major faults mapped in the studied area The spatial coincidence of some of these thermal centres with the are a of the highest residual Bouguer-anomaly values suggests that the hea t source ed the hydrothermal convection cells was a subvolcanic intrus ion. The minimum depth under the paleowater table of the mineralizatio n now exposed at the surface was about 200-440 m.