韓國 慶尙南道 彦陽圖幅 및 北西部 蔚山圖幅 地域産 花崗岩質岩의 K-Ar 年代

K-Ar dating on granitic rocks from the Eonyang and the northwestern part of Ulsan-quardrangle, Kyeongsang-nam-do, Korea

The K-Ar age determined on six granitic rocks samples from the Eonyang- and the northwestern part of Ulsan-quardrangle, Kyeongsang-nam-do, Korea, ranges from 87×10⁶ years to 58×10⁶ years. Three of the samples belong to the upper Cretaceous (87×10⁶-71×10⁶ years) and three to the late Cretaceous - early Tertiary (63×10⁶-58×10⁶ years) in age. The early Tertiary ages are measured first on the “Younger Granites” in Korea. These two emplacement periods of granitic rocks are representative that the former is correlated to north Kyushu-Seto Inland belt (95×10⁶-75×10⁶ years) and the later to Sanin-central Honshu belt (65×10⁶-50×10⁶ years), in southwestern Japan.