Through the 4.6 Gyr of Earth’s history, ore deposit has been formed via close linkage with the evolution of this planet. Ore deposit is an abnormally enriched material of targeted elements and its enrichment mechanism macro-scopically controlled by “Geology” and microscopically controlled by “Geochemistry”. “Front line of economic geol- ogy” is the third collaborative special issue by two Japanese academic journals of Chikyukagaku （Geochemistry） and Shigen-Chishitsu, aiming to review the metallogenesis, recent progresses and unsolved questions in each type of ore deposit for future researches on economic geology and geochemistry. This collaborative special volume is wrapped up by this issue 3.
