|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1999 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1998 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1997 : ¥1,700,000 (Direct Cost : ¥1,700,000)
The basements rocks of the Korean peninsula are Archean massifs mainly as a part of the Sino-Korean craton. Main Archean massifs of the Korean Peninsula are divided such as the Rangnim, Kyonggi and Ryongnam massifs. I visited to DPRK four times and collected the some rock specimens for the Rb-Sr and Sm-Nd isotope study. The Rb-Sr and Sm-Nd isotope analytical results of the Archean rocks of the Korean peninsula are as follows : Whole rock isochron ages of the Ryonhwasan Complex (the Rangnim Group (Hyansan)) indicate 1,214Ma (Rb-Sr age) and 1,980 Ma (Sm-Nd age). Whole rock isochron ages of the Rangnim massif (Huichon) indicate 1,857Ma (Rb-Sr age) and 1,831Ma (Sm-Nd age). Whole rock and mineral isochron indicates 1,836Ma, 2,122Ma and 2,872Ma (Sm-Nd age).
Whole rock isochron ages of the Kyonggi massif (Nampo) indicate 1,852Ma (Rb-Sr age) and 3,503Ma (Sm-Nd age), and the whole rock and mineral isochron indicates 2,745Ma and 3,260Ma. Whole rock isochron ages of the Kyonggi massif (Keson) indicate 829Ma (Rb-Sr age) and 3,529Ma (Sm-Nb age).
Besides the problem of the geological background about the analyzed specimens, we can read from these new geochronological data that the geological episodes had happened at the epochs of 3,500Ma, 2,700Ma 2,100Ma and 1,800Ma in Precambrian. The basements rocks of the Korean peninsula suffered from the evident poly metamorphism.