Abstract
Largely stratiform Kuroko deposits, stockwork ores and fissure-filling veins are widespread in the so-called Green Tuff basins of Tertiary age in Japan. They are the youngest, least modified examples known of base metal sulfide deposits associated with felsic lavas and pyroclastics, and familiarization with their features should lead to a more detailed appreciation of how and where other deposits of the same general types were formed.This paper summarizes the features of the Kuroko deposits and, in less detail, the associated nonstratiform deposits. It also discusses the genesis of the felsic volcanics and the ore fluids, comments on the differences between the Kuroko and other massive sulfide deposits, and lists factors which should be considered in the systematic exploration for base metal deposits in felsic volcanic sequences.