Se- and Te-type Au-Ag deposits

As shown in Fig. 1.117, Se-type and Te-type epithermal Au-Ag vein-type deposits are located in the Cretaceous-Quaternary volcanic terrane of Japan (e.g., northeast and southwest Hokkaido, middle Honshu, south Kyushu). Some Te-type deposits are located in regions similar to the Se-type deposits. Sometimes, Te mineralization is associated with the Se-type deposits, though Te minerals usually do not coexist with Se minerals. However, rarely, Te minerals coexist with Se minerals in the Te-type deposits (e.g., Teine, Suzaki, Kawazu, Iriki) on a polished section scale. For example, coexistence of native Te and Se-bearing tetrahedrite is found at Teine. Generally, Te mineralization occurs at 

K-Ar ages data on adularia and sericite in the veins and altered host rocks indicate that ages of mineralization vary widely, ranging from 1 Ma to 68 Ma and from 1 Ma to 24 Ma for the Se-type and Te-type, respectively (Tables 1.17 and 1.18). 

The total production of gold, silver and other associated base metals and silver/ gold production ratios from these deposits are summarized in Table 1.17. In addition to gold and silver, lead, zinc and manganese have been produced from some of the Se-type (e.g., Yatani) and copper has been produced from some of the Te-type (e.g., Teine, Kawazu). Total tonnage of production of Au and Ag from the Se-type is greater than 

Summary of geologic, mineralogic and geochemical characteristics of the Te-type and Se-type deposits (Shikazono et al., 1990) 

Host rocks Sedimentary rocks (dominantly shale), volcanic rocks (dacite and andesite) Volcanic rocks (dacite and andesite) 

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