Lead isotope mapping of galena from base metal deposits in the southern Korean Peninsula

The purpose of this study is to investigate the differences in sources of discrete four zones that are represented by the lead isotope map of metal mines using galena samples. The lead isotope map has been constructed based on 119 galena samples from 38 metal mines in the southern Korean Peninsula, together with previously published data, using spatial and zoning distribution analysis. The spatial pattern of Pb-206/Pb-204 ratio shows relatively dense distribution with highest value at the northeastern region, while Pb-207/Pb-204 and Pb-208/Pb-204 ratios are the lowest at the southeastern region. These results indicate possible subdivision of the lead isotope maps based on geotectonic subdivisions and geographical locations of the Korean Peninsula. This subdivision has been checked by linear discriminant analysis (LDA). The range of lead isotopic composition for zone 1 has fairly homogeneous values (Pb-206/Pb-204 = 18.156-18.591, Pb-207/Pb-204 = 15.482-15.644, and Pb-208/Pb-204 = 37.870-38.768), and are geographically similar to the Gyeongsang Basin. Lead isotopic compositions of zone 2 show the highest ratios (Pb-206/Pb-204 = 18.625-20.483, Pb-207/Pb-204 = 15.708-16.068, Pb-208/Pb-204 = 37.734-40.463) in the southern Korean Peninsula, that are geographically corresponding to the Taebaeksan Basin and the northeastern Yeongnam Massif. Relatively lower values (Pb-206/Pb-204 = 17.149-17.817, Pb-207 /Pb-204 = 15.497-15.731, Pb-208 /Pb-204 = 37.847-39.773) along the western Gyeonggi Massif are grouped as zone 4, while the rest of the areas, including the Okcheon metamorphic belt, most of the Gyeonggi Massif, and the Yeongnam Massif, might represent zone 3. The results clearly indicate the possible differences in the source reservoirs that are similar to the geotectonic provinces of the Korean Peninsula.