Download Relationships between volcanism and hydrothermal activity in the

Relationships between volcanism and hydrothermal activity in the Tokaj Mountains,
northeast Hungary, based on K-Ar ages
Pecskay Z, Molnar F
GEOLOGICA CARPATHICA
53 (5): 303-314 OCT 2002
Abstract:
Conventional K-Ar studies of volcanic rocks, rock-forming minerals and hydrothermal
adularia and alunite from different volcanic centres of the Tokaj Mts indicate that volcanic
activity took place between 15.2 and 9.4 Ma (Badenian-Sarmatian-Pannonian). In the
northern part of the Tokaj Mts, ages for the relatively deeply eroded hydrothermal systems
(Rudabanyacska and Telkibanya Au-Ag deposits and parts of the Regec caldera), formed
mainly by the adularia-bearing low-sulphidation epithermal deposits, are between 13.0 and
12.2 Ma. These systems were developed within andesitic-dacitic volcanic centres with
calderas and subvolcanic intrusions. In the southern parts of the Tokaj Mts (near Mad and in
the Szerenes Hills region) exposures of hydrothermal systems mainly represent shallow acidsulphate steam-heated zones of low-sulphidation-type systems, and the K-Ar ages are
between 12.1 and 10.4 Ma. Radiometric ages also suggest that in some parts of this latter area,
repeated hydrothermal activity occurred, suggesting that hydrothermal circulation developed
in relation to different magmatic centres that were active at different times.