Hokkaido is blessed with many ore deposits of many types: hydrothermal vein, Kuroko, skarn, placer etc.
In economic sense, hydrothermal Au-Ag, Hg, and Pb-Zn veins are the most important. Kuroko and stratiform massive sulfide deposits are the next. The Hg veins and stratiform massive sulfide deposits are distributed exclusively in the northeast of Hokkaido, while the Kuroko deposits and the majority of the Pb-Zn veins are in the southwest.
Placers of gold and platinum were actively mined since the Edo Era, the age of 'Samurai', until half a century ago. But they are almost mined out, and only a few are open for tourists' amusement.
Most of the deposits shown here are less than 20 million years old. An important exception is podiform chromite distributed within the Kamuikotan tectonic belt, which must be older than 100 million years.