K-Ar geochronology of the volcanism and associated metallogenesis in the Börzsöny Mountains, Hungary (dedikált példány) [antikvár]

k-ar geochronology of the volcanism and associated metallogenesis in the börzsöny mountains, northern hungary La'szlo Korpa's1 and Barbu Lang2 1- Hungarian Geological Survey, Budapest 2- Geological Survey of Israel, Jerusalem I. INTRODUCTION The Börzsöny Mountains volcanites, situated in northern In n ír Hungary, belong to those rare occurrences of the |-fHtpa)-Carpath i an continental margin-type volcanic arc outcrops, whose age is reliably dated by the underlying and overlying Badenian sedimentary complexes (Baldi and Kokai, 1970; Borza, 1973; Ba'ldine Beke, 1980; Ba'ldine' Beke et al., 1980). This volcanic area was investigated using numerous drillholes pa 1eomagnetic and K-Ar measurements. During the last 20 years, some 118 K-Ar determinations were carried out on 86 surface and drillhole samples; 35 additional dates were obtained in 1991 at the geochrono1ogica1 laboratory in Jerusalem. Based on biostratigraphic evidences, as well as on the pa 1eomagnetic and K-Ar data, it was possible to estimate the duration and the evolution in time of the volcanism: the volcanic activity took place in two phases within a short time interval; the K-Ar age is about 15,0+ 0.4 Ma (oceanic polarity anomaly aproximately 5B) ; its duration, assuming a N^RNg change in polarity, is between 400 to 700 Ky (Bal la and MaVtonne Szalay, 1978, 1980; Bal la et al., 1979,