Duration of Mineralization and Timing of Vein Formation at the Hishikari Epithermal Gold Deposit, Southern Kyushu, Japan, Determined by 40Ar/39Ar Dating

Abstract

To elucidate duration of mineralization and timing of vein formation at the Hishikari epithermal gold deposit, Japan, mineralization ages of individual bands within the Hosen-1 vein were determined using 40Ar/39Ar dating. Veins at the Hishikari deposit consist mainly of adularia and quartz, showing a precipitation sequence. Since adularia and quartz in the same sequence must have precipitated simultaneously, ages of adularia show timing of vein formation. The result of 40Ar/39Ar ages of adularia indicates that intervals among each vein formation varied from approximately 40,000 to 130,000 years and the total duration of mineralization at the vein was about 250,000 years. The veins were formed intermittently.