Ho Jeong Jo^1,2, Kyung-Seok Ko¹, Dong-Chan Koh¹ and Jong-Sik Ryu³, (1)Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea, (2)Chonbuk National University, Jeonju, South Korea, (3)Pukyong National University, Department of Earth and Environmental Sciences, Busan, South Korea