Japanese Iodine-Geology And Geochemistry

The geological and geochemical characteristics of the Japanese iodine-rich brines are outlined. The iodine-rich brine in Japan is primary in its origin and its occurrence is limited in the younger marine sediments. The iodine-rich subsurface water is saturated or over- saturated by natural gas, but the water saturated by natural gas is not always rich in iodine. The iodide and bromide contents decrease with time. The bromide content decreases much more rapidly than that of iodide. It should be emphasized that the genetic environment of the Japanese type of dissolved gas and iodine deposit is not peculiar to the Japanese islands.