*W.L.A.C.I. Weedagama ^1,2、N.W.B. Balasooriya²、Atula Senaratne²、Bhathiya Athurupana²、Rohana Chandrajith²、Nadeesha H. Koralegedara² (1.Post Graduate Institute of Science, University of Peradeniya, Peradeniya, Sri lanka、2.Department of Geology, University of Perdeniya, Peradeniya, Sri Lanka)