K-Ar ages of adularia at the Koryu epithermal Au-Ag deposit,Hokkaido in Japan

摘要

Four new K-Ar ages of adularia at the Koryu Au-Ag epithermal vein deposit along with the mineralization stages were determined. One age is 1.4 Ma for the first mineralization stage and the other three ages are 1.19-1.10 Ma for the most economically important Au-Ag mineralization stage. Combined with published data of K-Ar ages, mineral description, and fluid inclusion study, the results suggest that the hydrothermal activities waxed and waned, forming ore veins with ten mineralization stages for 0.55 million years in the Koryu deposit.