K-Ar age is determined on the granitic rocks which were obtained from Eonyang and Ulsan quadrangle areas, southeastern part of Korean peninsula. The purpose of this paper is to determine the early Tertiary age in Korea, using the K-Ar method.
The measured ages of eight granitic rocks range from 87×10
6 to 48×10
6 years. Three of the samples belong to the upper Cretaceous(87×10
6-71×10
6 years) and five to the late Cretaceous-early Tertiary(63×10
6-48×10
6 years) in age. The first age determination of the early Tertiary in Korea is pressented.
These two emplacement periods of granitic rocks are representative that the former is correlated to north Kyushu-Seto Inland belt (95×10
6-75×10
6 years) and the later to Sanin central Honshu belt (65×10
6-50×10
6 years), in southwestern Japan.
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