| Abstract |
To examine the relationship between siliceous sinter and epithexmal gold mineralization, sinter samples were collected from thirteen locations in Japan. The samples were analyzed by X-ray difltactometry and X-ray fluorescence spectrometry. The samples were also analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for the quantitative determination of gold. The dominant silica minerals change from opal-A (younger than 10 ka), through opal-CT with quartz (10 ka to 1 Ma) and finally to quartz (older than 1 Ma). Most sinter in the distal location from the discharge site contains less than 0.02 wt % Ti02 and 0.5 wt % A1203. Higher concentrations of Ti02, A1203 and K20 can be explained by contamination of detrital materials. The concentration of gold in sinter ranges 0.1-827 ppb and shows a bimodal distribution, which corresponds to gold mineralization. |